Mineralogy

June 2009
Volume 5, Number 3
ISSN 1811-5209
Gems
emmanuel fritsch and benjamin rondeau, Guest Editors
Gemology: A Developing Science
Gem Formation, Production,
and Exploration
Geochemistry of Gems
Identifying Faceted
Gemstones
Synthetic Gems
Laboratory-Treated
Gemstones
Pearls and Corals:
“Trendy Biomineralizations”
Elements is published jointly by the Mineralogical
Society of America, the Mineralogical Society
of Great Britain and Ireland, the Mineralogical
Association of Canada, the Geochemical Society,
The Clay Minerals Society, the European
Association for Geochemistry, the Inter­national
Association of GeoChemistry, the Société
Française de Minéralogie et de Cristallographie,
the Association of Applied Geochemists,
the Deutsche Mineralogische Gesellschaft,
the Società Italiana di Mineralogia e Petrologia,
the International Association of Geoanalysts,
the Polskie Towarzystwo Mineralogiczne
(Mineralogical Society of Poland), the Sociedad
Española de Mineralogía, and the Swiss Society
of Mineralogy and Petrology. It is provided as a
benefit to members of these societies.
Elements is published six times a year. Individuals
are encouraged to join any one of the partici­
pating societies to receive Elements. Institutional
subscribers to any of the following journals
—American Mineralogist, Clay Minerals, Clays and
Clay Minerals, Mineralogical Magazine, and The
Canadian Miner­alogist—will also receive Elements
as part of their 2009 subscription. Institu­tional
subscriptions are available for US$150 a year in
2009. Contact the managing editor (tremblpi@
ete.inrs.ca) for information.
Copyright 2009 by the Mineralogical Society
of America
All rights reserved. Reproduction in any form,
including translation to other languages, or by
any means—graphic, electronic or mechanical,
including photocopying or information storage
and retrieval systems—without written permission
from the copyright holder is strictly prohibited.
Volume 5, Number 3 • June 2009
Gems
Emmanuel Fritsch and Benjamin Rondeau, Guest Editors
147
153
Gemology: The Developing
Science of Gems
Emmanuel Fritsch and Benjamin Rondeau
The term gem covers a large
range of products: single
crystals, amorphous minerals,
organics, rocks, imitations,
synthetics, treated stones,
faceted or rough objects, and
even assemblages of various
materials. See page 148 for
details. Photo by R. Weldon,
courtesy GIA
Gem Formation, Production, and Exploration: Why Gem
Deposits Are Rare and What Is Being Done to Find Them
Lee A. Groat and Brendan M. Laurs
159
The Geochemistry of Gems and Its Relevance to
Gemology: Different Traces, Different Prices
George R. Rossman
163
The Identification of Faceted Gemstones:
From the Naked Eye to Laboratory Techniques
Bertrand Devouard and Franck Notari
169
Seeking Low-Cost Perfection:
Synthetic Gems
Robert E. Kane
175
Laboratory-Treated Gemstones
179
Pearls and Corals: “Trendy Biomineralizations”
James E. Shigley and Shane F. McClure
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Departments
Editorial – Gems, Riches, Wealth and Finance . . . . . . . . . . . . 139
From the Editors – Elements and GeoScienceWorld. . . . . . . 140
Letter to the Editors. . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Triple Point – Asbestos Sans Mineralogy. . . . . . . . . . . . . . . . 141
People in the News – Boatner, Farfan, Hawthorne . . . . . . . . 142
Obituaries – Deines, Rösler . . . . . . . . . . . . . . . . . . . . . . . . 144
Meet the Authors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
Society News
International Association of Geoanalysts. . . . . . . . . . . . . . . . 181
Mineralogical Society of Great Britain and Ireland . . . . . . . . 182
Geochemical Society. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184
The Clay Minerals Society. . . . . . . . . . . . . . . . . . . . . . . . . . . 185
Mineralogical Society of America. . . . . . . . . . . . . . . . . . . . . 186
Mineralogical Association of Canada . . . . . . . . . . . . . . . . . . 188
Deutsche Mineralogische Gesellschaft . . . . . . . . . . . . . . . . . 190
Mineralogical Society of Poland . . . . . . . . . . . . . . . . . . . . . . 191
Société Française de Minéralogie et de Cristallographie. . . . 192
Meeting Reports – Applied Mineralogy Meeting,
MSA–GS short course. . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
Outreach – Why Teach Mineralogy?. . . . . . . . . . . . . . . . . . 196
Book Reviews – LA–ICP–MS in the Earth Sciences . . . . . . . . . . 197
Calendar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
Parting Shots – Gaga over Gemstones. . . . . . . . . . . . . . . . 200
Advertisers in this Issue . . . . . . . . . . . . . . . . . . . . . . . . . 200
Printed in Canada
ISSN 1811-5209 (print)
ISSN 1811-5217 (online)
www.elementsmagazine.org
137
PARTICIPATING SOCIETIES
The Mineralogical
Society of America is
composed of indivi­duals
interested in mineralogy,
crystallography, petrology,
and geochemistry. Founded
in 1919, the Society promotes,
through education and research, the under­
standing and application of mineralogy by
industry, universities, government, and the
public. Membership benefits include special
subscription rates for American Mineralogist
as well as other journals, 25% discount on
Reviews in Mineralogy & Geochemistry
series and Mono­graphs, Elements, reduced
registration fees for MSA meetings and short
courses, and participation in a society that
supports the many facets of mineralogy. For
additional information, contact the MSA
business office.
Society News Editor: Andrea Koziol
(Andrea.
[email protected])
Mineralogical Society of America
3635 Concorde Pkwy Ste 500
Chantilly, VA 20151-1110, USA
Tel.: 703-652-9950; fax: 703-652-9951
[email protected]
www.minsocam.org
The Mineralogical
Society of Great Britain
and Ireland, also known
as the MinSoc, is an inter­
national society for all
those working in the
mineral sciences. The
Society aims to advance the knowledge of
the science of miner­alogy and its applica­
tion to other subjects, including crystallog­
raphy, geochemistry, petrology, environ­
mental science and economic geology. The
Society furthers its aims through scientific
meetings and the publication of scientific
journals, books and mono­graphs. The
Society publishes Mineralogical Magazine
(print and online) and Clay Minerals (print
and online). Students receive the first year
of membership free of charge. All members
receive Elements.
Society News Editor: Kevin Murphy
([email protected])
The Mineralogical Society
12 Baylis Mews, Amyand Park Road
Twickenham, Middlesex TW1 3HQ, UK
Tel.: +44 (0)20 8891 6600
Fax: +44 (0)20 8891 6599
[email protected]
www.minersoc.org
ship benefits include reduced registration fees
to the annual meeting, discounts on the
CMS Workshop Lectures, and Elements.
Society News Editor: Steve Hillier
([email protected])
The Clay Minerals Society
3635 Concorde Pkwy Ste 500
Chantilly, VA 20151-1125, USA
Tel.: 703-652-9960; fax: 703-652-9951
[email protected]
www.clays.org
The Geochemical Society
(GS) is an international
organization with members
from 54 countries, founded
in 1955 for students and
scientists involved in the
practice, study and teaching
of geochemistry. Our programs include
co-hosting the annual Goldschmidt
ConferenceTM, editorial oversight of
Geochimica et Cosmochimica Acta (GCA),
supporting geochemical symposia through
our Meeting Assistance Program, and
supporting student development through
our Student Travel Grant program. Addi­
tionally, GS annually recognizes excellence
in geochemistry through its medals, lectures
and awards. Members receive a subscription
to Elements magazine, special member rates
for GCA and G-cubed, publication discounts,
and conference discounts.
Society News Editor: Seth Davis
([email protected])
Geochemical Society
Washington University
Earth & Planetary Sciences
One Brookings Drive, Campus Box #1169
St. Louis, MO 63130-4899, USA
Tel.: 314-935-4131; fax: 314-935-4121
[email protected]
Explore GS online at www.geochemsoc.org
The European ­Association
for Geochemistry was
founded in 1985 to promote
geochemical research and
study in Europe. It is now
recognized as the premiere
geochemical organi­zation
in Europe encouraging interaction between
geoche­mists and researchers in asso­cia­ted
fields, and promoting research and teaching
in the public and private sectors.
Society News Editor: Michael J. Walter
([email protected])
The Mineralogical
­Association of Canada
was incorpor­ated in 1955
to promote and advance
the knowledge of miner­
alogy and the related disci­
plines of crystal­lography,
petrol­ogy, geochemistry, and economic
geology. Any person engaged or inter­ested
in the fields of mineralogy, crys­tallography,
petrology, geo­chemistry, and economic
geology may become a member of the Asso­
ciation. Membership benefits include a
subscrip­tion to Elements, reduced cost for
sub­scribing to The Canadian Mineralogist, a
20% discount on short course volumes and
special publica­tions, and a discount on the
registration fee for annual meetings.
Society News Editor: Pierrette Tremblay
([email protected])
Membership information:
www.eag.eu.com/membership
The International
­ ssociation of
A
GeoChemistry (IAGC) has
been a pre-eminent inter­na­
tional geo­chemical organi­
zation for over 40 years. Its
principal objectives are to
foster cooperation in, and advancement of,
applied geo­chemistry, by sponsoring specialist
scientific symposia and the activities organized
by its working groups and by support­ing its
journal, Applied Geochemistry. The adminis­tra­
tion and activities of IAGC are conducted by
its Council, comprising an Executive and ten
ordinary members. Day-to-day administration
is performed through the IAGC business office.
Society News Editor: Mel Gascoyne
([email protected])
IAGC Business Office, Box 501
Pinawa, Manitoba R0E 1L0, Canada
[email protected]
www.iagc.ca
Mineralogical Association of Canada
490, de la Couronne
Québec, QC G1K 9A9, Canada
Tel.: 418-653-0333; fax: 418-653-0777
[email protected]
www.mineralogicalassociation.ca
The Clay Minerals
Society (CMS) began as the
Clay Minerals Committee
of the US National Academy
of Sciences – National
Research Council in 1952.
In 1962, the CMS was
incorporated with the primary purpose of
stimu­lating research and disseminating
information relating to all aspects of clay
science and technology. The CMS holds an
annual meeting, workshop, and field trips,
and publishes Clays and Clay Minerals and
the CMS Workshop Lectures series. Member­
The Société Française
de Minéralogie et de
Cristallographie, the
French Mineralogy and
Crystallography Society,
was founded on March 21,
1878. The purpose of the
Society is to promote mineralogy and
­crystallography. Member­ship benefits include
the “bulletin de liaison” (in French), the
European Journal of Miner­alogy, Elements, and
reduced registration fees for SFMC meetings.
SFMC
Campus Boucicaut, Bâtiment 7
140 rue de Lourmel
75015 Paris, France
www.sfmc-fr.org
bulk rock and micro-analytical methods,
the production and certification of reference
materials and the publication of the Asso­
ciation’s official journal, Geostandards and
Geoanalytical Research.
The Association of
Applied ­Geochemists is
an international organiza­
tion founded in 1970 that
specializes in the field of
applied geochemistry. Its
aims are to advance the
science of geochem­istry as it relates to
exploration and the environment, further
the common interests of exploration
geochemists, facilitate the acquisition and
distribution of scientific knowledge,
promote the exchange of information, and
encourage research and development. AAG
membership includes the AAG journal,
Geochemistry: Exploration, Environment,
­Analysis; the AAG newsletter, EXPLORE;
and Elements.
Society News Editor: Michael Wiedenbeck
([email protected])
Society News Editor: David Lentz
([email protected])
Association of Applied Geochemists P.O. Box 26099 Nepean, ON K2H 9R0, Canada Tel.: 613-828-0199; fax: 613-828-9288 [email protected]
www.appliedgeochemists.org
The Deutsche
­Mineralogische
­Gesellschaft (German
Mineralogical Society)
was founded in 1908 to
“promote miner­alogy and
all its subdisciplines in
teaching and research as well as the personal
relationships among all members.” Its great
tradition is reflected in the list of honorary
fellows, which include M. v. Laue, G. v.
Tschermak, P. Eskola, C.W. Correns, P.
Ramdohr, and H. Strunz, to name a few.
Today, the Society especially tries to support
young researchers, e.g. to attend conferences
and short courses. Membership benefits
include the European Journal of Mineralogy,
the DMG Forum, GMit, and Elements.
Society News Editor: Michael Burchard
([email protected])
Deutsche Mineralogische Gesellschaft
[email protected]
www.dmg-home.de
The Società Italiana
di Mineralogia e
­Petrologia (Italian Society
of Mineralogy and Petro­
logy), established in 1940,
is the national body repre­
senting all researchers
deal­ing with mineralogy, petrology, and
related disciplines. Membership benefits
include receiving the European Journal of
Mineralogy, Plinius, and Elements, and a
reduced registration fee for the annual meeting.
Society News Editor: Marco Pasero
([email protected])
Società Italiana di Mineralogia e ­Petrologia Dip. di Scienze della Terra
Università di Pisa, Via S. Maria 53
I-56126 Pisa, Italy
Tel.: +39 050 2215704 Fax: +39 050 2215830
[email protected]
www.socminpet.it
The International Association of Geoanalysts is
a worldwide organization
supporting the profes­sional
interests of those involved
in the analysis of geological
and environmental mate­
rials. Major activities include the manage­
ment of proficiency testing programmes for
The Polskie
­ owarzystwo MineralT
ogiczne (Mineralogical
Society of Poland), founded
in 1969, draws together
professionals and amateurs
interested in mineralogy,
crystal­lography, petrology, geochemistry,
and economic geology. The Society
promotes links between mineralogical
science and education and technology
through annual conferences, field trips,
invited lectures, and publish­ing. There are
two active groups: the Clay Minerals Group,
which is affiliated with the European Clay
Groups Association, and the Petrology
Group. Membership benefits include
subscriptions to Mineralogia and Elements.
Society News Editor: Zbigniew Sawłowcz
([email protected])
Mineralogical Society of Poland
Al. Mickiewicza 30, 30-059 Kraków, Poland
Tel./fax: +48 12 6334330
[email protected]
www.ptmin.agh.edu.pl
The Sociedad Española
de Mineralogía (Spanish
­Mineralogical­­ Society) was
founded in 1975 to promote
research in mineralogy,
petrology, and geochem­
istry. The Society organizes
annual conferences and furthers the training
of young researchers via seminars and
special publications. The SEM Bulletin
published scientific papers from 1978 to
2003, the year the Society joined the European Journal of Mineralogy and launched
Macla, a new journal containing scientific
news, abstracts, and reviews. Membership
benefits include receiving the European
Journal of Mineralogy, Macla, and Elements.
Society News Editor: Jordi Delgado
([email protected])
Sociedad Española de Mineralogía
[email protected]
www.ehu.es/sem
The Swiss Society of
Mineralogy and
Petrology was founded in
1924 by professionals from
academia and industry and
by amateurs to promote
knowledge in the fields of
mineralogy, petrology and geochemistry and
to disseminate it to the scientific and public
communities. The society coorganizes the
annual Swiss Geoscience Meeting and
publishes the Swiss Journal of Geosciences
jointly with the national geological and
paleontological societies.
Society News Editor: Urs Schaltegger
([email protected])
Swiss Society of Mineralogy and Petrology
Université de Genève
Section des Sciences de la Terre
et de l’Environnement
13, rue des Maraîchers
1205 Genève, Switzerland
Tel.: +41 22 379 66 24; fax: +41 22 379 32 10
http://ssmp.scnatweb.ch
Affiliated Societies
The International Mineralogical Association, the
European Mineralogical Union, and the International
Association for the Study of Clays are affiliated
societies of Elements. The affiliated status is reserved for those organizations that serve as
an “umbrella” for other groups in the fields of min­er­a logy, geochemistry, and petrology,
but that do not themselves have a membership base.
Society News Editor: Anne Marie Karpoff
([email protected])
E lements
International Association of Geoanalysts­
13 Belvedere Close
Keyworth, Nottingham NG12 5JF
United Kingdom
http://geoanalyst.org
138
J une 2009
EDITORIAL
principal editors
Susan L. S. Stipp, Københavns Universitet,
Denmark ([email protected])
David J. Vaughan, The University of
Manchester, UK
(david.vaughan@
manchester.ac.uk)
Harry Y. (Hap) McSween, University of
Tennessee, USA ([email protected])
Advisory Board 2009
John Brodholt, University College London
Norbert Clauer, CNRS/UdS, Université de
Strasbourg, France
Roberto Compagnoni, Università degli
Studi di Torino, Italy
James I. Drever, University of Wyoming, USA
Will P. Gates, SmecTech Research
Consulting, Australia
George E. Harlow, American Museum of
Natural History, USA
Janusz Janeczek, University of Silesia, Poland
Hans Keppler, Bayerisches Geoinstitut,
Germany
David R. Lentz, University of New Brunswick,
Canada
Maggi loubser, University of Pretoria,
South Africa
Anhuai Lu, Peking University, China
Robert W. Luth, University of Alberta, Canada
David W. Mogk, Montana State University, USA
Takashi Murakami, University of Tokyo, Japan
Roberta Oberti, CNR Istituto di Geoscienze
e Georisorse, Pavia, Italy
Eric H. Oelkers, LMTG/CNRS, France
Terry Plank, Lamont-Doherty Earth
Observatory, USA
Xavier Querol, Spanish Research Council, Spain
Olivier Vidal, Université J. Fourier, France
Meenakshi Wadhwa, Arizona State
University, USA
Executive Committee
Giuseppe Cruciani, Società Italiana di
Mineralogia e Petrologia
Barbara L. Dutrow, Mineralogical
Society of America
Rodney C. Ewing, Chair
David A. Fowle, Mineralogical Association
of Canada
Catherine Mével, Société Française
de Minéralogie et de Cristallographie
Marek Michalik, Mineralogical Society
of Poland
Manuel Prieto, Sociedad Española
de Mineralogía
Clemens Reimann, International Association
of GeoChemistry
Urs Schaltegger, Swiss Society of
Mineralogy and Petrology
clifford r. stanley, Association
of Applied Geochemists
Neil C. Sturchio, Geochemical Society
Andrew Thomas, The Clay Minerals Society
Peter Treloar, Mineralogical
Society of Great Britain and Ireland
Friedhelm von Blanckenburg, Deutsche Mineralogische Gesellschaft
Michael J. WALTER, European Association
for Geochemistry
Michael Wiedenbeck, International
Association of Geoanalysts
Managing Editor
Pierrette Tremblay, [email protected]
Editorial office
490, rue de la Couronne
Québec (Québec) G1K 9A9 Canada
Tel.: 418-654-2606
Fax: 418-654-2525
Layout: Pouliot Guay graphistes
Copy editor and proofreader: Thomas Clark
Printer: caractéra
The opinions expressed in this maga­z ine are
those of the authors and do not necessarily
reflect the views of the publishers.
www.elementsmagazine.org
Gems, Riches, Wealth and Finance
As I sit down to write this
editorial, the world is faced
with the greatest financial
cr isis since the Great
Depression of the 1930s, pos­
sibly the greatest such crisis
ever. It is perhaps an ironic
coincidence that the theme
of this issue of Elements con­
cerns the highest-value
materials we take from the
David Vaughan1
Earth, the gemstones which
have been symbols of wealth
and power since the earliest civilisations. But we
should not forget that the beauty of even the most
modest of precious and semi-precious stones has
also given great pleasure to many of us at one
time or another.
Balanced against this ever growing harvesting of
Earth resources, there are dangers for our fragile
planet in careless exploitation and utilisation of
those resources. The most immediate danger, as
is now well known, is that associated with global
warming and related climate change. Public, but
above all political, awareness of the dangers asso­
ciated with the changes in atmospheric chemistry
due to the burning of fossil fuels and to other
industrial processes has been slow to develop. The
melting of the great ice sheets and the retreat of
glaciers at an alarming rate is a matter of record,
and the overwhelming majority of climate scien­
tists are warning of the dangers of increased
carbon dioxide and other greenhouse gases
heating the surface of the Earth and leading to
rising sea levels and extreme climatic excursions,
whether storms or droughts. The generally inad­
equate response of governments to the threat of
climate change seems partly due to an unwilling­
ness to pay attention to bad news (especially
when a very small minority of experts take an
opposing view) and an unwillingness to take mea­
sures that relate to medium-to-long-term planning,
i.e. extending beyond the three-, four- or five-year
horizon associated with national elections.
Whereas the present financial crisis is a reminder
of human greed and folly, gemstones are a
reminder of the fact, not always appreciated by
our political masters, that almost all of our mate­
rial wealth comes from the Earth. As scientists
specialising in Earth materials and Earth systems,
we know only too well that this wealth is not
limitless. Recent decades have seen a phenomenal
increase in the volume of raw mate­
The wealth of our Earth resources
rials extracted from the Earth.
is limited and our planet is fragile,
Although supplies of some, like
or rather, the very thin layer
building stone and abundant metals
extending from the top few metres
Gemstones are
such as iron or aluminium, are so
of soil, or from the waters of seas
a reminder…
vast as to ensure supplies into the
and oceans, and up through the
that almost all
indefinite future, for others, local
lower atmosphere – the so-called
or even global shortages are likely
‘critical zone’ – is fragile. People
of our material
to arise relatively soon. The most
speak about ‘saving the planet’, but
wealth comes
obvious examples of this are the
the Earth itself is not under threat,
from the Earth… only what goes on in that critical
fossil fuels, particularly oil and gas,
this wealth is
but more alarming are warnings
zone and, in turn, the survival of a
over future supplies of water for
wide range of life forms, including
not limitless.
drinking and other domestic use,
homo sapiens. The use of the quali­
and for the irrigation of crops. Some
fier sapiens, from the Latin “wise”,
might advocate a return to a simpler
could prove an unfortunate irony.
way of life (living ‘off the land’), but that is not
But, humankind has long proved incredibly
an option with a world population of six and a
inventive and resourceful, and there is another
half billion people and which is bound to grow
form of wealth to add to that of our Earth’s
by several billion more in the coming decades. It
resources, that of human ingenuity. It may be
is also important to remember that feeding,
that our financial systems face unprecedented
clothing and housing our current population is
challenges, but they are as nothing compared to
only possible through the operation of complex
the threat to our continued existence as a species.
systems involving numerous types of raw mate­
Great ingenuity will be needed to provide the
rials and technological and agricultural products.
resources for an Earth population of nine to ten
For example, world food production has only kept
billion people, or even more, and the expertise
pace with population growth through efficient
of Earth scientists (sensu lato) will have to play a
irrigation systems, modern fertilisers based largely
central role. This will not only be in helping to
on mining of chemical minerals, and agricultural
develop new sources and types of raw materials
machines such as tractors and combine har­
and fuels, as well as systems and strategies to
vesters, which themselves require numerous
avoid irreparable damage to the Earth’s critical
materials, particularly metals, drawn from the
zone, but also in persuading our governments to
Earth for their construction.
address these problems with even more urgency
than they have devoted towards rescuing failed
financial systems.
David J. Vaughan
([email protected])
1 David Vaughan was the principal editor
in charge of this issue.
E lements
139
J une 2009
FROM THE EDITORS
This Issue
With this issue, Guest Editors Emmanuel
Fritsch and Benjamin Rondeau bring us into
the fascinating world of gems and the chal­
lenges faced by people who study or work
with them. In Parting Shots, George Harlow
reminds us of the glamour and romance asso­
ciated with some famous stones. Among our
other features, two of them discuss asbestos,
a term that has been misused by the legal
and medical community: read Triple Point
by Mickey Gunter (page 141) and Outreach
by Tomas Feininger (page 196). As usual we are
grateful to the authors of this issue for their
diligence in meeting the deadlines and their
willingness to keep working at their articles
after multiple edits, and we thank all our con­
tributors.
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a couple of months, the sample issue will be
“Deep Earth” (v4n3).
Moreover, all the non-thematic content in
Elements (Book Reviews; Editorial, Triple Point,
Society News, etc.) is posted on GSW and is
available to all.
2008 Financial Statements
Elements closed 2008 with
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a net positive bal­
ance of $28,335. Income was $308,729 and
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of $615 per published page). Our income
came mainly from society contributions (56%),
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will continue.
While catching up on my reading, I went through your
thought-provoking article Lost in Translation in the
February issue of Elements. I wanted to let you know
that there are a few of us (not many though) who do
get involved in the application of Earth sciences to
societal problems. Since 1980 I have been applying
isotopic techniques, primarily Pb and Sr, to many local
problems—many involve hydrocarbon releases.
I developed what is called the ALAS model
(Anthropogenic Lead ArchaeoStratigraphy), which
has been used quite effectively since 1992 to estimate the year of leaded gasoline releases. I also,
more recently, completed a study of lead paint in
homes in order to assess the potential impact of lead
on residents. The problem is that most of my work
is “under the scientific radar,” being performed and
supported by geotechnical firms and, of course,
attorneys’ clients who are being sued.
However, on the bright side, the vast majority of my
cases have been resolved with contamination being
cleaned up by the responsible party or parties. From
the standpoint of NSF/EPA funding, I believe that
university scientists are not going to get funds to
work on a corner gas station issue; nor will they take
on such projects in lieu of supporting graduate students and their own research.
My training was under George Wetherill, then at
UCLA, where I worked in the Labrador Archean and
on the Sudbury Impact Structure (early/mid-1970s).
I happened to change my focus somewhat: as I tell my
students, the age of the geologic materials I have
worked on throughout my career has been inversely
proportional to my age. So, I really appreciate your
concern on this matter, and perhaps an issue of
Elements might, in the future, solicit input from folks
like me who work, not on global issues, but on matters
of a more local nature, where people’s lives are indeed
impacted. Thanks so much for your time and efforts.
Pierrette Tremblay
Managing Editor
Richard W. Hurst, Hurst & Associates, Inc.
www.hurstforensics.com and Professor Emeritus
Geology/Geochemistry – CSU, Los Angeles, USA
Back issues of Elements are now available
Order online at www.elementsmagazine.net
E lements
140
J une 2009
TRIPLE POINT
Asbestos Sans Mineralogy
It would come as a shock to a mineralogist if
you heard a judge say “the definition of asbestos
is a legal matter” (stemming from debate on
which species of amphiboles should be consid­
ered asbestos), or saw the phrase “naturally
occurring asbestos” (used to denote asbestos
occurring in its natural setting), or heard a fed­
eral agency in charge of worker safety propose
the phrase “elongated mineral particle” to
express a concern about the health effects of
all minerals three times longer than they are
wide, or, my favorite, read that a court recently
Mickey Gunter
defined asbestos as “a fibrous non-combustible
compound that can be composed of several
substances, typically including magnesium.” Note that “mineral” was
left out of the latter definition; thus, the meaning of my title, and the
reality that in all of these examples there was no input from the min­
eralogical community.
places where commercial asbestos had been used, as in an asbestos
mining or milling operation or in an asbestos abatement project.
However, when these methods move into the natural world they fail,
as most nonasbestiform amphiboles would meet this counting criterion,
and thus many geological materials (e.g. mafic rocks, sediments derived
from them, and amphibole-containing construction materials) would
be subject to some type of regulation.
And now comes the issue of “naturally occurring asbestos (NOA).” This
phrase was what originally prompted me to write this editorial. It
appears that this term was first used in the Sacramento Bee (March 29,
1998) in reference to tremolite asbestos “unearthed” during a housing
construction project. After the Sacramento Bee article, a California state
geology report was issued also using the acronym NOA, but to their
credit they defined it as “natural occurrences of asbestos.” However,
the definition coined in the Sacramento Bee seems to have won out. My
issue, as a mineralogist and someone concerned with helping the public
understand these issues, is when people see the phrase “naturally occur­
ring asbestos,” they would naturally think there must also be non­
natural asbestos and not interpret the term as it was intended (i.e. to
denote asbestos not occurring in an industrial setting). We must stop
this imprecise use of scientific terminology. Yes, I also
dislike the phrases “carbon footprint” and “organic
food”!
I believe asbestos basically moved out of the minds of
most mineralogists a decade or so ago. At that point,
society had realized there were health issues in mining
…under these
The current trend among regulatory and law-making
and milling asbestos in the pre–regulated workplace (i.e.
nonmineralogical
groups, at least in the United States, seems to be to
before the 1970s). Then, concern moved from the work­
definitions of
broaden the definition of asbestos to include all elon­
place to the schoolhouse, with the 1990s seeing asbestos
gated mineral particles, which would, of course, include
abatement in those settings. However, it was the min­
asbestos, most
such common rock-forming minerals as quartz, feldspar,
eralogy community that pointed out there are major
of our world
and calcite. And one such group is the United States
differences in the health effects of chrysotile asbestos
would be naturally
Congress, where bills have been proposed to ban
when compared to amphibole asbestos, the latter being
asbestos. Although many may agree that the use of
contaminated.
more harmful. There are five regulated amphiboles, with
asbestos in commercial products should be stopped, I
only two of commercial importance: crocidolite, the
think we would all disagree with how asbestos was
asbestiform variety of riebeckite, and amosite, the
defined in these bills, based on aspect ratio or, more
asbestiform variety of grunerite. The other three regu­
generally, defined as elongated mineral particles. I believe it is critical
lated amphiboles are tremolite, actinolite, and anthophyllite when they
for us to make our voices heard and bring our mineralogical expertise
occur in the asbestiform habit; this they rarely do, and instead are
to bear on these asbestos issues, mainly to point out that under these
common rock-forming minerals occurring in many geological settings.
nonmineralogical definitions of asbestos, most of our world would be
In the late 1990s, asbestos concerns reemerged based mainly on two
naturally contaminated. If we stay uninvolved in this, and in other
issues: the former vermiculite mine near Libby, Montana, which con­
mineralogical issues important to society, we may find someone has
tained trace amounts of amphiboles in the ore, and the “discovery” of
defined a mineral as “a substance made of compounds.”
“naturally occurring asbestos” near El Dorado Hills, California.
Historically, the amphiboles associated with the vermiculite deposit in
Libby had been referred to as tremolite. However, as attention turned
toward the health effects of these amphiboles, it became apparent that
the majority of the amphibole asbestos species at the mine were
winchite and richterite, with less than 10% being tremolite. And
because winchite and richterite were not regulated, a legal question
emerged: was worker exposure to asbestiform varieties of these minerals
a crime? Based upon Libby and the occurrence of other nonregulated
asbestiform amphiboles (e.g. fluoro-edenite in Biancavilla, Sicily), now
there are recommendations that all asbestiform amphiboles should be
regulated. Although this seems like a logical conclusion, one that I
have somewhat naively supported in the past, the real issue, then,
becomes how one defines asbestiform and nonasbestiform amphiboles;
but before we tackle that definition, it is worth noting why we care.
Although debated, there appears to be a difference in the disease poten­
tial between amphibole particles derived from asbestiform amphiboles
and those derived from nonasbestiform ones, the latter being less
harmful. The central issue is the difference in how asbestiform amphi­
bole is defined by mineralogists and the regulatory agencies. A miner­
alogist would define “asbestiform” as a type of morphology character­
ized by a lengthwise splitting into fibers, and we, in turn, would define
a fiber as being flexible, much like a human hair. The regulatory com­
munity “counts” a particle as a “fiber” based on its aspect ratio (length
divided by width). A particle examined with a light microscope would
be considered a fiber if its aspect ratio were greater than 3. This counting
method had merit when used to count particles in air samples from
E lements
141
Mickey Gunter
University of Idaho ([email protected])
Read also Tomas Feininger’s text on page 194.
Topical Session #78
at Geological Society of America
Annual Meeting • Portland, Oregon
“Issues surrounding exposure to asbestos and
other potentially hazardous fibrous minerals
occurring in their natural settings”
In this session we hope to bring together geologists,
mineralogists, industrial hygienists, regulators, and public
policy makers to address the set of issues that have arisen
due to increasing concerns about exposure to asbestos
minerals in their natural settings.
The deadline for abstract submission is August 11
(11:59 pm, PDT).
Abstracts can be submitted at:
http://gsa.confex.com/gsa/2009AM/cfp.epl
J une 2009
PEOPLE IN THE NEWS
Lynn A. Boatner New Fellow
of the Materials Research Society
FRANK Hawthorne Inducted into
Russian Academy of Sciences
Lynn A. Boatner, an adjunct professor
in the Universit y of Tennessee
Department of Materials Science and
Engineering, has been named a Fellow
of the Materials Research Society.
Boatner’s citation for this recognition
reads: “For pioneering, sustained, and
innovative contributions to the funda­
mental understanding, processing and
applications of single crystals, nano­
composites, rare-earth and actinide
compounds, and scintillators.” Lynn A.
Boatner, an Oak Ridge National
Laboratory Corporate Fellow, is the
director of the ORNL Center for Radiation
Detection Materials and Systems, and
he leads the Synthesis and Properties of Novel Materials Group in the
ORNL Materials Science and Technology Division. He holds a PhD
degree in physics from Vanderbilt University. Boatner is a Fellow of the
American Physical Society, the American Ceramic Society, the American
Association for the Advancement of Science, the Materials Research
Society, the Mineralogical Society of America, ASM International, and
the Institute of Materials, Minerals, and Mining of the United Kingdom.
He is the recipient of three IR-100 Awards (1982, 1985, 1996), the Frank
H. Spedding Award for Excellence in Rare Earth Research, the Jesse W.
Beams Prize of the American Physical Society Southeastern Section,
the Elegant Work Prize of the Institute of Materials, Minerals, and
Mining of the United Kingdom, the Francis F. Lucas Award of the
American Society for Metals International, The Pierre Jacquet Gold
Medal Award of the International Metallographic Society, the AACG
Crystal Growth Award of the American Association for Crystal Growth,
a Federal Laboratory Consortium Award for Excellence in Technology
Transfer, and a U.S. Department of Defense Innovative Technology
Award. He is a member of the Academy of Sciences of Mexico and has
received a DOE Award for Significant Implications for Energy Technology
in Solid State Physics. Boatner recently served as the chair of the
Division of Materials Physics of the American Physical Society, and he
is the founder and curator of the Single Crystal Growth Collection and
Exhibit of the American Association for Crystal Growth. He has pub­
lished over 530 scientific articles and holds 14 U.S. patents.
Frank Hawthorne (Department of Geo­
logical Sciences, University of Manitoba)
was inducted into the Russian Academy of
Sciences as a Foreign Member at the annual
meeting of the Division of Earth Sciences,
Russian Academy of Sciences, on December 15,
2008. He was nominated by the Institute of
Geology of Ore Deposits, Petrography, Miner­
alogy, and Geochemistry, RAS (Academician
Nikolai Bortnikov, Director). Academician
Nikolai Laverov, Vice-President of the Russian
Academy of Sciences, made the presentation.
Frank Hawthorne began collaborative work with Russian scientists in
the late 1990s, and his work with members of the Russian scientific
community in Moscow has gradually expanded since that time. His
initial collaboration with Professors Vadim Kazansky and Konstantin
Lobanov, IGEM RAS, on the rocks of the Kola Superdeep Borehole, was
promoted by Dr. Elena Sokolova (University of Manitoba, IGEM RAS).
His work is now focused on the crystal chemistry of the constituent
amphiboles and micas and their relations with temperature and pres­
sure of equilibration and variations in lithogeochemistry. Frank
Hawthorne and Elena Sokolova work extensively with Leonid Pautov,
Atali Agakhanov, and Vladimir Karpenko of the Fersman Mineralogical
Museum, RAS, Moscow, on the minerals of the Dara-i-Pioz alkaline
massif in northern Tajikistan, and with Professor Alexander Khomyakov,
Institute of Mineralogy, Geochemistry and Crystal Chemistry of Rare
Elements, Moscow, on the minerals of the Khibina and Lovozero mas­
sifs (Kola Peninsula).
High School Mineralogist Wins
Intel Talent Search Award
Gabriela Farfan, a senior student
of Madison West High School,
won 10 th place in the Intel Talent
Search based on her Oregon sun­
stone research, carried out in the
Department of Geology and
G e ophysic s, Un iver sit y of
Wisconsin. Under the guidance of
Prof. Huifang Xu, Gabriela used
optical microscopes, XRD, and
SEM to identify micro- and nano­
precipitates of native copper and
closely associated Fe-bearing
enstatite in gem-quality labradorite phenocrysts from Lake Country,
Oregon. She proposed a relationship between observed color changes
in the sunstones and the crystallographic orientations of the precipi­
tates inside the host crystals. Gabriela also presented her research results
at the 2008 Goldschmidt Conference in Vancouver, Canada.
The Intel Science Talent Search, a program of Society for Science & the
Public (SSP), is an annual competition that identifies the nation’s most
promising scientists of the future and celebrates the best and brightest
young minds as they compete for one of the most esteemed honors
bestowed on high school seniors in the United States.
E lements
142
J une 2009
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OBITUARIES
Peter Deines
1936–2009
PROFESSOR Hans Jürgen Rösler
Professor Peter Deines, an authority on
1920–2009
isotope geochemistry, is well known for
his research on the nature of diamonds,
Prof. Hans Jürgen Rösler, internationally
for his services to the Geochemical Society,
renowned mineralogist and geochemist,
and for his skilled editing of the Isotope
died peacefully in Freiberg, Germany, on
Geoscience Section of Chemical Geology for
12 January 2009. Hans Jürgen Rösler
nearly two decades. His passion was the
made significant contributions to miner­
precise measurement of isotope ratios and
alogy, petrology, and geochemistry. His
their evaluation for resolving deep geologic
textbook
processes. He died at age 72 in State College,
“Geochemical Tables” by Rösler and
Pennsylvania, on February 2, 2009, after a
Lange were benchmark publications with multiple editions, and
protracted bout with cancer.
are still in use by many. Spurenelemente in der Umwelt (Trace Elements
and
the
Tharandt in 1987, was an outstanding contribution, particularly
when considering the conditions in the GDR.
The Professor Emeritus for Mineralogy and Honorary Senator of
TU Bergakademie Freiberg was an appointed active member of the
Saxonian Academy of Science, a member of the geosciences section
of the Russian Academy of Sciences (St. Petersburg), an honorary
member and a recipient of the Serge-von-Bubnoff Medal of the
Gesellschaft für Geologische Wissenschaften of the GDR, as well
as a recipient of many other awards and distinctions. Rösler started
studying mining engineering at Bergakademie Freiberg in 1947,
soon switched to geology, and later became the first alumnus of
the newly introduced course in mineralogy. Following his PhD
dissertation in 1954 on the geochemistry of anthracite, he took
over the mineralogical and geochemical laboratories of the
Geological Survey in Jena. He returned to TU Bergakademie
Freiberg in 1959 to follow Prof. Friedrich Leutwein as the Chair of
Mineralogy and Geochemistry. Hans Jürgen Rösler taught until
1985 and, in spite of the difficult conditions in the GDR, he devel­
oped the institute into a leading institution in the geosciences,
with outstanding infrastructure and attractive research opportuni­
ties, even for international scientists. In the mid-1960s, the insti­
tute was among the finest academic institutions worldwide, with
a permanent staff of 60 scientists and technicians and state-ofthe-art infrastructure. Leadership in IAGOD and the IMA reflect
this reputation. More than 300 scientific papers, 77 successful
doctoral students, and 17 postdocs (habilitations) also mark his
activities. The geoscience community will miss Hans Jürgen Rösler,
an outstanding person, colleague, and friend.
In 1981, Peter was elected treasurer of the Geochemical Society and
established its first budgeting and financial planning system, refining
it until 1988. In appreciation of that contribution, he was awarded by
the Society a unique Honorary Life Membership. Furthermore, he pro­
vided crucial service to all of geochemistry as chairman of the
Goldschmidt Conferences of 1988–1990 and as cochair in 1991–1992
and 1994–1995.
Peter was internationally recognized and admired, especially for his
fundamental contributions to our perception of the stable isotope geo­
chemistry of the mantle. An exacting experimentalist, Peter maintained
over four decades an exceptionally fruitful collaboration with Jeff
Harris, University of Glasgow. Those investigations resulted in a com­
prehensive database of the C and O isotope profiles for all types of
diamonds and some associated minerals from every kimberlite pipe in
southern Africa and dozens more across the globe. Specifically, he deter­
mined C and O isotope ratios in a variety of mantle minerals, including
diamond, graphite, carbonates, moissanite, and silicate solid solutions,
and also in xenoliths, as well as C in organic compounds from the
mantle and C in the mantle gases CO2, CH4, and CO of fluid inclusions.
E lements
mineralog y
in the Environment), published with Hans Joachim Fiedler from
Born in Hann. Münden, Germany, he earned his Geologie Vordiplom
at Friedrich Wilhelms University in Bonn, then an MSc and, in 1967,
his PhD in geochemistry and mineralogy at Penn State University.
Recognizing a gem, Penn State appointed him as a professor in geo­
chemistry, a position he retained until his nominal retirement in 2004,
after which he played an active role as Professor Emeritus. He carried
an extraordinary level of academic responsibilities, including over 60
administrative posts and university committees, of which two were
advisory to the president of the university. To support his teaching, he
wrote two web books: Solved Problems in Geochemistry (www.geosc.psu.
edu/courses/Solved_Problems/index) and Stable Isotope Geochemistry
Course Notes (www.geosc.psu.edu/courses/Geosc518/Stable_Isotopes/
index). The College Wilson Award was given to him in recognition of
his consummate teaching of geochemistry.
These studies led to many seminal discoveries, such as the revelation
at Jagersfontein of sublithospheric diamonds that were highly enriched
in 12C. He also made the first systematic study of C isotope geochemistry
in diamonds with sulfide rather than oxide inclusions, a correlation
that implied diamond crystallization from fluids rather than magmas.
Another milestone was the discovery, made together with Steven
Haggerty, that small-scale isotopic variations in ultradeep (>300 km)
mantle xenoliths relate to metasomatic modification only a few million
years prior to kimberlite eruption. Peter thought deeply about the largescale implications of his findings, and when his isotope fractionation
models contradicted popular hypotheses, he did not shy from contro­
versy. In particular, Peter never accepted the concept that subduction
of organic material generated the light C signatures (δ13C < -15‰)
observed in mantle xenoliths and diamonds with eclogitic inclusions.
on
Jörg Matschullat, Jens Gutzmer,
and Gerhard Heide, Freiberg
In carefully written monographs that will endure as touchstones for
decades to come, he steadfastly argued that the bimodal distribution
of C isotopes in the mantle is unrelated to the introduction of crustal
C; rather, he proposed that thermodynamic isotope effects, possibly
involving C dissolved in mantle minerals, resulted in the generation
of distinct C reservoirs.
Those of us who were privileged to work with Peter remember him for
his modesty, his generosity, and his dedication to his science, students,
and colleagues.
144
Hu Barnes, Penn State University
Thomas Stachel, University of Alberta
Peter Heaney, Penn State University
J une 2009
Bertrand Devouard is
an assistant professor at
the Laboratoire Magmas
& Volcans at the Blaise
Pascal University in
Clermont-Ferrand,
France. He graduated
from the ENSG in Nancy,
France, and completed his PhD at the University
of Marseille in 1995. He worked as a post­
doctoral fellow in RUCA-EMAT (Belgium)
and in the 7*M group at Arizona State
University. His research focuses on the rela­
tionship between microstructures, properties,
and growth processes of crystals. He applies
electron microscopies, microdiffraction,
microanalyses, and spectroscopies to the
study of a wide range of materials. His
interest in gems began when he contracted
for a project on ruby chemistry at the GIA
research laboratory in 1990.
Emmanuel Fritsch is a
professor of physics at the
University of Nantes in
western France. He holds
a geological engineering
degree from the ENSG,
Nancy, France, and a PhD
from the Sorbonne in
Paris. He worked for nearly ten years at the
Gemological Institute of America (GIA) and
was manager of GIA Research from 1992 to
1995. He currently conducts research at the
Institut des Matériaux Jean Rouxel (IMN-CNRS)
in Nantes. His interests include advanced
techniques applied to gemology, color in gems
(especially diamonds), treated and synthetic
gems, opals, and pearls.
Jean-Pierre Gauthier
is a retired professor of
physics at the University
of Lyon I, France. His
research focused mostly
on crystallographic
structures revealed by
means of transmission
electron microscopy and electron diffraction.
After various studies on the surface properties
of metals and semiconductors treated by ion
implantation or chemical vapor deposition,
he oriented his work towards synthetic
inorganic materials (like polytypism in
industrial moissanite, the subject of his PhD)
and gems (special arrays of silica spheres in
opal), including biominerals (shells, pearls,
and coral). He is also interested in optical
phenomena in gemstones: interferences,
diffraction, chatoyancy, and asterism.
Lee A. Groat is a pro­
fessor in the Department
of Earth and Ocean
Sciences at the University
of British Columbia,
Canada. He received his
doctorate from the
University of Manitoba
and was a NATO Postdoctoral Fellow at the
University of Cambridge. His research interests
include the crystal chemistry of minerals,
the geology of gem deposits, and granitic
pegmatites, and he has published approximately
100 scientific papers and book chapters. He
was editor of American Mineralogist from 2001
to 2005. In 1999 he received the Young
Scientist Award of the Mineralogical Association
of Canada, and in 2003 he became a Fellow
of the Mineralogical Society of America.
Robert E. Kane is
president and CEO of
Fine Gems International
in Helena, Montana. He
began his career at the
GIA Laboratory, where
he was manager of gem
identification from 1978
to 1992. After pursuing independent research
and gem exploration, he was named director
of the Gübelin Gemmological Laboratory in
Switzerland in 1996. Mr. Kane has traveled
internationally to gem sources and is well
known for his research articles and lectures
on diamonds, colored stones, and gem iden­
tification. Many of his award-winning arti­
cles have been published in Gems &
Gemology, where he has served on the editorial
review board since 1981.
Stefanos Karampelas
is a postdoctoral fellow
at Gübelin Gemmological
Laboratory in Lucerne,
Switzerland. His research
focuses on the identifica­
tion and quality grading
of pearls. His work also
includes nondestructive spectroscopy applied
to organic gems and other gem materials. He
obtained his doctorate jointly from the Aristotle
University of Thessaloniki, Greece, and the
University of Nantes, France, where he studied
the nature and detection of pigments in natural
and treated pearls and corals.
Brendan M. Laurs is
editor of Gems & Gemology
at the Gemological
Institute of America (GIA)
in Carlsbad, California.
He is a gemologist and
geologist specializing in
the formation of gem
deposits. He obtained a BS degree in geology
at the University of California Santa Barbara
in 1991 and an MS degree in geology from
Oregon State University in 1995. Brendan
worked as an exploration geologist for colored
gemstones (benitoite and red beryl) with
Kennecott Exploration Co. in 1995 and then
moved to GIA in 1996. He received his Graduate
Gemologist diploma from GIA in 1997, and
in 2006 he cochaired, with Jim Shigley,
GIA’s first-ever Gemological Research
Conference in San Diego.
Shane F. McClure is
director of West Coast
Identification Services at
the GIA Laboratory in
Carlsbad, California, USA.
He has been a contributing
author on many articles
published in GIA’s quar­
terly journal Gems & Gemology, as well as in
many other publications. He won Gems &
Gemology Most Valuable Article award seven
times in the 1990s. In 2007 he was the recip­
ient of the Antonio C. Bonanno Award for
excellence in gemology. Mr. McClure is also
a coeditor of the Gem Trade Lab Notes section
of Gems & Gemology and an accomplished
gem and jewelry photographer and
photomicrographer.
Franck Notari is
director of the independent
laboratory GemTechLab
in Geneva, Switzerland,
which he established in
1998. He was also labo­
ratory manager and
research manager at GIA
for two years. He obtained his DUG diploma
(University of Nantes) in 1996 on Padparadscha
sapphires. He has published numerous articles,
particularly on colored diamonds and colored
gems (spinel, tanzanite, euclase, etc.). He
also gives laboratory gemology classes at the
University of Nantes on the detection of
treatment (corundum, tanzanite, black
diamond, etc.) and synthetic gem identifica­
tion. Franck Notari mainly carries out research
on corundum (geographical origin, treat­
ment, synthesis) and on colored diamonds.
Cont’d on page 146
E lements
145
J une 2009
MEET THE AUTHORS Cont’d from page 145
Benjamin Rondeau is
an assistant professor
of Earth sciences at the
University of Nantes,
France. He received his
PhD from the Muséum
National d’Histoire
Naturelle (MNHN) in
Paris, France. For nine years, he was assistant
curator of the collections of rocks, minerals,
and gems at the MNHN. He was also highly
involved in the 2001 Diamonds exhibit. His
research focuses on the geological conditions
of gem formation and on the properties of
gem materials.
George R. Rossman
received his PhD in inor­
ganic chemistry from
Caltech, where he is now
Professor of Mineralogy.
His research involves the
use of spectroscopic probes
to study minerals. These
methods directly address the origin of color
in minerals and gems. He has also studied
biominerals, weathering products, and radia­
tion-damaged minerals, including long-term
color changes in minerals that result from
exposure to background levels of natural
radiation. He was the recipient of the inaugural
Dana Medal of the Mineralogical Society
of America.
James E. Shigley is a
distinguished research
fellow at the GIA
Laboratory of the
Gemological Institute
of America in Carlsbad,
California. Prior to joining
GIA in 1982, he earned a
bachelor’s degree from the University of
California, Berkeley, and a PhD in geology
from Stanford University. His main research
interest is characterizing natural, synthetic,
and treated gem materials in order to develop
practical means for their identification.
DUG – University of Nantes – France
An internationally
recognized advanced
diploma in gemology
Small groups, hands-on
education in high-tech
laboratory
Contact:
[email protected]
More on
www.gemnantes.fr
E lements
146
J une 2009
Gemology: The Developing
Science of Gems
Emmanuel Fritsch1 and Benjamin Rondeau2
1811-5209/09/0005-0147$2.50 DOI: 10.2113/gselements.5.3.147
P
rompted by the increasing number of laboratory-grown gems and the
growing sophistication of treatments of natural stones, gemology has
evolved into a science of its own. The discipline is rapidly incorporating
relevant aspects of materials science and chemistry, and it is consolidating
its activities and its terminology. Gemology is becoming an important area
of specialization for mineralogists. If the study of beautiful, fashioned materials
seems frivolous to some, it is worth noting that 20 to 25 billion dollars per
year are at stake, and the study of natural gem materials and their treated
and manufactured counterparts is essential in order to avoid frauds and
protect the consumer.
has evolved from a trade practice
to a recognized science. Its economic
field of application is the gems and
jewelry trade. About 150 billion
dollars’ worth of gems and jewelry
are sold annually. Gems by themselves are worth 20 to 25 billion
dollars, with the lion’s share (about
85%) accounted for by diamond.
Gems are mined worldwide, but
some countries, such as Brazil, Sri
Lanka, Myanmar, Australia, and
Madagascar, have acquired over the
Keywords : gemology, gems, history of gemology, gem treatment,
years a reputation for producing
gem terminology, synthetic gems
many or particularly beautiful gems.
Shigley et al. (2000) provide a
detailed list of gem-producing localINTRODUCTION
ities, and a world map of these was edited by Gübelin (1994).
Diamonds, rubies, emeralds, jade, pearls—these are the
seeds of many dreams (Fig. 1). Gems are associated with In this issue, we address key aspects of gemology. Groat
love and romance, but also with power, money, and the
and Laurs (2009) explain how gems grow in nature and
plundering of riches. Gems have always played an integral how they are extracted. Rossman (2009) details the role of
role in cultures worldwide. One can be dazzled one minute
geochemistry in characterizing gemstones, while Devouard
by splendid jewelry glistening on stars at the Academy and Notari (2009) address the problem of identifying the
Awards, and the next minute hear about the embargo on
exact nature of faceted gems. Shigley and McClure (2009)
Burmese gems. Let us not forget that, for a gem to be a true
provide an overview of important gem treatment processes
treasure, it must be authentic. This is where gemologists
and their detection, while Kane (2009) introduces synthetic
play an important role. At first, it was just a matter of gems. Gauthier and Karampelas (2009) also present a brief
recognizing an imitation, and a good knowledge of minerals, account of pearls and corals as biomineral gems.
combined with a keen sense of observation, was all that
was needed. But soon, people tried to modify and improve
GEMS ARE NOT SO EASY TO DEFINE
gems. Even the ancient Egyptians heated agate to give it a
Gems are materials used for adornment or decoration that
more attractive color. The production of “Egyptian blue”
(cuprorivaite), a turquoise look-alike, can be considered a must satisfy several criteria: they must be relatively rare, hard,
and tough enough (shock resistant) to resist “normal” wear and
starting point of crystal growth technology. This “new
withstand corrosion by skin contact (sweat) and cosmetics.
technology” eventually led in the 19th century to the first
gem rubies and emeralds grown by man (Nassau 1980).
For centuries, gemology was exclusively a branch of mineralogy, as most gems were natural minerals. The expansion
in production of man-made gems in the 1970s and 1980s
and the explosion in the number and sophistication of
gem treatment processes since the 1990s have spurred a
more multidisciplinary approach. Gemology now incorporates
elements of spectroscopy, materials physics, chemistry, and
even some biology (e.g. in work on pearls). Today, gemology
1 Université de Nantes, CNRS-Institut des Matériaux Jean Rouxel (IMN)
UMR 6502, 2 rue de la Houssinière, BP 32229
F-44322 Nantes cedex 3, France
E-mail: [email protected]
2 Université de Nantes, Laboratoire de Planétologie et Géodynamique
CNRS UMR 6112, 2 rue de la Houssinière, BP 92208
F-44322 Nantes cedex 3, France
E-mail: [email protected]
E lements , V ol . 5,
pp.
147–152
This very general definition calls for several comments.
The notion of rarity is relative. If a gem is too rare, it tends
to be less well known and is less expensive, as there is not
enough of it to build a market. A number of gems fit into
the category of “rare stones”—they belong to the domain
of specialized collectors; examples include jeremejevite,
taaffeite, and preobrazhenskite. In fact, less than 200 materials are considered relatively common gems; the rest are
“rare” (see Fritsch 1992). Nevertheless the price of a rare
stone can be increased by a strong marketing campaign,
as has been the case for benitoite and red beryl. Also,
although most common gems are relatively hard and
tough, a number of gems are interesting precisely because
they are difficult to facet (brucite and halite are excellent
examples) and so cannot be mounted in jewelry. These are
for “collectors on paper,” as such fragile pieces are usually
kept in a “fold,” a piece of paper folded several times over
to safely hold the specimen.
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J une 2009
The vast majority of gems are natural minerals. This led
to the expression “precious stones.” According to culture and
country, this term typically encompasses (at least) diamond,
ruby, sapphire, and emerald. For a given gem, only a few
varieties are highly priced, and the rest do not truly deserve
the term precious [for example, a 50 carat (ct) D-flawless
diamond versus a 3 mm diameter brown or black faceted
diamond, or a 15 ct bright blue faceted Paraíba tourmaline
versus a 1 ct dark green tourmaline cabochon (cab); Fig. 2].
Not all gems are precious, as a number of gemstones are
moderately priced (Fig. 3). This is why we prefer the expression “gem materials” or simply “gems.” These terms better
cover the large variety of products found in the jewelry
market today. Needless to say, we recommend not using the
term “semiprecious stones,” which, in our view, is meaningless. In addition, not all “stones” or minerals are of interest
to gemologists, who work only on those that can be fashioned into gems or are known as inclusions in gems, and
these represent a limited subset of the existing mineral species.
Finally, not all gems are “stones”—pearls are a notable
example (Fig. 1).
A natural gem is one that has been fashioned (or faceted)
after having been found in nature, even if it later undergoes
treatment processes. Among natural gems, most are single
crystals. However, others are amorphous (opal, natural glass),
some are not pure species but solid solutions (garnets,
peridot), others are rocks (jade, lapis), and some are composed
partly or wholly of organic materials (amber, pearl, coral,
etc.) (Fig. 1).
“Fakes”
Among gem materials, there are several types of “fakes.”
The oldest historically are imitation gems—fashioned
stones that look like more valuable materials but have a
different structure and composition. Only imitations would
be considered fakes by gemologists. Imitations have been
produced since antiquity because beautiful natural gems
are so rare. Some experts distinguish imitations (still natural
gems) from simulants, which are man-made products (Fritsch
1992). Until the early twentieth century, heat-treated colorless zircon was the most common diamond imitation.
Synthetics are laboratory-grown materials with the same
crystal structure and chemical composition (apart for
impurities) as their natural counterparts (Kane 2009 this
A
B
The term gem covers a large range of products: single
crystals, amorphous minerals, organics, rocks, imitations,
synthetics, treated stones, faceted or rough objects, and even assemblages of various materials. This composite picture shows (from top
to bottom): a natural jadeite-jade carving; lapis lazuli with matrix,
accompanied by a high-quality lapis cabochon; a precious boulder
opal-A from Queensland, Australia; a pear-shaped, briolette-cut
near-colorless glass; a slightly dissolved octahedral diamond crystal;
a gem intarsia by N. Medvedev (containing malachite, opal, lapis,
turquoise, and purple sugilite); a red andesine feldspar; a berylliumdiffused, orangey-red sapphire (right); a dyed, green jadeite cabochon;
and five white to golden, South Seas, beaded, cultured pearls.
Photo by R. Weldon, courtesy GIA
Figure 1
E lements
Not all tourmalines are of equal value. This fairly
common green tourmaline (A) is relatively inexpensive,
whereas the blue Cu-colored “Paraíba” tourmaline (B) may sell for
thousands of dollars per carat. The mineralogical nature of a gem
species does not directly command its value. The precise variety and
its locality of origin are also determining factors. Incidentally, a
“Paraíba” tourmaline can be more precious than some emeralds or
sapphires. The stones weigh 13.12 and 70.74 ct, respectively.
Photographs by Wimon Manorotkul/www.palagems.com
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Figure 2
J une 2009
issue). Synthetic gems have been around for well over a
century (Fig. 4), as melted and recrystallized natural ruby
was sold as “Geneva ruby” starting in 1885.
Treated gems are objects (either natural or synthetic) that
have undergone a treatment process to modify their appearance, usually their color or purity (Shigley and McClure 2009
this issue), for example, worthless light-colored sapphire
made orange by beryllium diffusion at high temperature.
Some names are much more appealing than others. To
make the material commercially more attractive, a lookalike stone of lesser value borrows the name of a glamorous
cousin, with the addition of a local or locality name, to avoid
flat-out identity theft. For example, “Herkimer diamond”
is certainly not diamond, but a bright, colorless, bipyramidal
quartz found near Herkimer in New York State; similarly,
grossularite garnet from South Africa glorifies itself as
“Transvaal jade.” Any scientifically inadequate or deliberately ambiguous name is termed a misnomer. This category
does not include confusing names of specific gems such as
the “Black Prince Ruby,” which has been known to be a
spinel for quite some time (ruby and spinel were confused
in the past, spinel then being referred to as “balas ruby”).
Composite gems are made of several materials assembled
together. A very common example is the opal doublet or
triplet. Nice play-of-color opal is rare and is often found as
a fragile filling in very thin seams. To circumvent these
frustrations, thin opal slices are glued, as in a sandwich,
between a black base highlighting color and a mechanically
resistant, rounded, colorless top (often quartz or glass). These
opal “triplets” look like regular opal cabochons, and they
help put on the market beautiful pieces that otherwise would
be hard to sell. At the other end of the spectrum, stone mosaics
called “intarsia”, made with no intent to deceive, play on
the boldness of color and a sharp geometrical pattern to
create one true gem out of many fragments (Fig. 1).
Engineered gems are man-made but have no natural equivalents. The raw material is often natural, but is modified
to give an aspect (color, most often) never encountered in
nature. The road to engineered gems was opened by Aqua
Aura quartz, colorless quartz made aquamarine blue by a
thin film of gold. The material was hugely successful. Today,
topaz is also coated with a thin metallic film, providing
different colors and optical effects–an example is “mystic
topaz”. All in all, as many as 500 different materials can probably be considered as gems, and the list continues to grow.
Diamonds and Colored Stones
There has been a historical divide between diamonds and
“colored stones,” an expression meaning in essence “everything but diamond.” The distinction is sometimes inadequate, as colorless varieties of other species then become
“colorless colored stones,” whereas colored diamonds
remain in the “diamonds” category and not in the “colored
stones” one! These two broad categories are often considered as belonging to different fields, with their own specialists and practices, and even different, often unrelated,
training courses. This is nonsensical from a scientific standpoint, but no better system has been proposed so far.
Contrary to popular belief, synthetic gems have been
available for over a century. The first commercial
“synthetic” was the Geneva ruby, circa 1885. This ring (top right)
contains nine such synthetic rubies, easily recognized by their strong,
internal, curved striae (bottom right), which are derived directly from
a rather brutal melting and mixing process. The text of this postcard
(printed in 1904; left) advertising Geneva rubies reads “Oriental ruby is
the most sought-after gem and, as a consequence, the most expensive,
its price being far greater than that of the brilliant. We have discovered
the means to agglomerate small parcels of natural oriental rubies
by melting them at 2000°C. Therefore, we offer to the public the
reconstituted oriental ruby. It has all the qualities of natural oriental
ruby since the material is the same, as well as the density, hardness,
and refringence. Our production and cutting workshops are equipped
with all the improvements of modern mechanics, which make it
possible for us to solve this problem: make available to all budgets a
precious stone that, until now, was accessible only to millionaires.”
Figure 4
This string of beads (courtesy John Saul) from Ethiopia is
made of various fragments: glass, pottery, agate beads,
chalcedony, and metal chips. All of these materials have very little
commercial value, if any. However, as they are considered worth being
worn as jewels by the owner, they are gem materials. For more details
on the nature of these gems, see http://gemnantes.fr/research/
others/ethiopia.php.
Figure 3
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A MULTIDISCIPLINARY SCIENCE
Gemology is the science of gems. Its core business is the
identification of gem materials, first by establishing their
identity and then by determining whether they are natural
or synthetic and if they have been treated (Webster 1975;
Liddicoat 1987; Hurlbut and Kammerling 1991; Devouard
and Notari 2009 this issue) (Figs. 5 and 6). Also, quality
grading of diamonds (the famous “4Cs”: carat, color, clarity,
cut) is an important part of gemology. Quality grading of
pearls has recently been introduced, and various systems
for colored stones (particularly with respect to their color)
have been proposed, even if none is universally accepted.
The geographical origin of gems is also an important
specialty, as some colored stones have significantly higher
value if they can be recognized as coming from certain
preferred deposits: blue sapphires from Kashmir have always
commanded higher prices than those from Burma or Sri
Lanka, for example. It is interesting to note that over a century
ago, the same was true of diamond: Indian diamonds were
worth more than those from Brazil, themselves more valuable than South African newcomers (Jannettaz et al. 1881).
This distinction disappeared with the introduction of a
detailed quality-grading system. Hence, the locality-of-origin
issue is today akin to branding, a marketing procedure.
Related Fields
In an effort to understand—or even better, predict—criteria
for identification or determination of geographical origin,
gemology often involves related fields of expertise. For
example, crystal growth studies help the gemologist understand growth structures often visible inside faceted gems
and the formation of inclusions as a function of the growth
environment. These optical features can be especially useful
in establishing the locality of origin for a gem, and whether
it is natural or synthetic. The geology of gem deposits is
fundamental to understanding the nature of inclusions and
trace elements (Fig. 7). Of course, such knowledge eventually leads to the development of prospecting guidelines, and
hence helps ensure future production of gems and, ultimately, market stability (Groat and Laurs 2009 this issue).
More recently, geochemistry has become an important part
of gemology. The development of trace element analysis
and isotope gemology has contributed criteria that can also
help distinguish between natural and synthetic gems or
identify geographical origin (Rossman 2009 this issue). An
understanding of the origin of color is fundamental, as the
value of a gem is often related to its color, especially the
stability of that color and whether it is natural or treatmentinduced. The related property of luminescence is an integral
part of gem identification, but is not always well understood.
E lements
These five stones (ranging in weight from 2.38 to 4.18 ct)
look like natural emeralds, and it takes a gemologist to
tell them apart, using simple tools available in a jewelry store. From left
to right, natural emerald, synthetic YAG (yttrium aluminum garnet),
glass, fluorite, synthetic emerald. Photograph by R. Weldon, courtesy GIA
Figure 5
New Techniques and Instrumentation
The foundation of gemology is observation, because it is
extremely useful, yet quick and nondestructive. As observation does not require complex, expensive instrumentation,
there was a perception that gemology was not very scientific. However, simple solutions are the most elegant, and
one should not use complex machines if the correct scientific answer can be gained by adequate use of one’s sight.
This negative perception is fading away, as, since the 1960s,
gemologists have become major users of optical spectroscopic techniques, starting with ultraviolet–visible–near
infrared absorption spectroscopy, then mid-infrared, and
more recently Raman scattering and a variety of luminescence techniques. Many of the fields of investigation
mentioned above can benefit from such techniques:
UV–visible absorption spectroscopy is fundamental for
color-related problems, and infrared spectroscopy helps in
the detection of minor constituents such as water, CO2,
and organic impregnation materials, some of which are
relevant to the geology of gem deposits and to the identification of treated or synthetic gems (Fig. 6). Gemologists
are also frequent users of various microscopic techniques,
such as optical and electron microscopy. The development
of spectroscopic methods at the microscopic scale for
specific gemological use is continuing.
Terminology Issues
One of the first steps for a science is establishing a correct
classification of relevant objects or concepts. Gemological
nomenclature still requires some clarification as it develops
from a trade practice into a science. A key issue currently
is the conflict between a scientific terminology and one
that is more acceptable commercially but occasionally
incorrect or ambiguous. For example, synthetic opal, a
commercial term accepted for decades, covers materials
that contain silica but no water (such as Gilson synthetic
opal), although a true synthetic should contain all components of natural opal (SiO2 ·nH 2O), including water (e.g.
Schmetzer 1983). There is considerable debate today on
how far merchants can go in the language they use to
advertise synthetic diamonds: “man-made” and “laboratorygrown” are accepted, but “cultured” is not approved by
many international organizations.
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The term graining is a good example of a poorly defined
concept: it is used for many different phenomena, virtually
all concerning diamond, including variation of indices of
refraction in colorless diamonds (simply “graining”); pink
or brown lamellae alternating with colorless ones (“colored
graining”)(Fig. 8); green luminescence zoning in brown
diamonds (“fluorescent graining”); minute inclusions in
white diamonds (“whitish graining”); and difference in
hardness, for example, at growth sector limits (“hardness
graining”. There is even reflective graining (seen in purple
diamonds) and iridescent graining. In most cases, some
local variation of index of refraction is associated with
another physical phenomenon, so “graining” might be
narrowed to just that first characteristic in the list.
Unfortunately, in materials science and even mineral
physics, graining has a different meaning and refers to the
fact that a crystal is constituted of different grains.
A
THE GEMOLOGICAL CROWD
A gemologist is a practitioner of gemology and is, therefore,
able to correctly and efficiently identify and grade gem
materials (Fig. 5). Very few gemologists practice “full time.”
These would include laboratory gemologists, working in
the main gem labs around the world, mostly grading
diamonds. There are probably a few dozen “research gemologists,” people dedicating their time to gemological
research. Among them, only some are scientists by training.
Most gemologists practice gemology in addition to a range
of related activities. Jewelers create jewels and art objects
using gem materials. They must know the physical and optical
properties of gemstones in order to mount them safely
(some can break easily) and aesthetically (some change
color with direction, for example). The same is true for cutters,
who transform rough gem materials into faceted gemstones.
Retailers need gemological knowledge to buy and sell gems
and gem-set jewelry and adequately evaluate repairs (for
example, to make sure a diamond brought in for retipping
of prongs has not been fracture-filled). Wholesalers and rough
dealers sell faceted and rough gems, respectively. They
obviously have a strong financial interest in distinguishing
“true” from “fake” gems. This is also the case for experts
(judicial, insurance, customs), who are legally responsible
for providing information regarding gems (either mounted
or not), and appraisers, who assign the commercial value of
a gem at a given time. Archeogemologists study gems from
past civilizations. They first have to identify them correctly.
A growing part of archeogemology is the reconstruction
of trade routes, hence the strong interest in the determination of geographical origin. Last but not least, gemology
attracts a number of enthusiastic amateurs, who are often
the driving force in associations and local gem clubs.
That few scientists and many trade people are involved has
contributed to the perception that gemology is not a
science, a view not uncommon among geologists and physicists. This is accentuated by the rarity of academic gemology
B
Gemologists often need to use several classical gemology
and laboratory methods to resolve an issue. One half
of the sapphire in the ring (A, inset) has been heat treated to a
desirable transparent blue from an initial valueless milky appearance.
High-temperature treatment is revealed by optical microscopy (B);
the zircon inclusion in the top-right corner has melted and now looks
like a whitish sphere (“golf ball” inclusion), and needle-like TiO2 (silk)
inclusions in the center have been partially dissolved and now appear
as dotted lines. 40x magnification. Transmission infrared spectroscopy
(A) provides further information: the peak at 3309 cm -1 and its
companions indicate heat treatment under reducing conditions, with
capture of an H atom by an Fe–Ti pair (red spectrum), absent in the
untreated part (blue spectrum). Ring photo courtesy Pascal Entremont
Figure 6
E lements
Inclusions in gems often give a strong indication of the
geological environment of formation of the host gem.
In this spectacular eagle-head-shaped fluid inclusion in colorless beryl,
three daughter crystals have been identified (15x magnification). The
sharp-faced, partially terminated crystal nearest to the bubble is
quartz, and the more granular or fragmented portion in the ruff of
feathers on the eagle’s neck is albite. There are some tiny needles as
well, too small to identify, but which are suspected to be tantalite by
analogy with other, larger, needle-shaped inclusions commonly
found in beryl. This indicates that all three minerals are present in the
pegmatite in which this gem was discovered. Photo by J. Koivula
Figure 7
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J une 2009
For any science, precise terminology is essential. However,
in gemology, some terms are still poorly defined and
therefore confusing. As an example, the term graining refers to many
phenomena occurring in parallel planes, including color lamellae in
pink and brown diamonds (left, field of view ~4 mm), green fluorescence
(middle, field of view ~6.5 mm), and high-optical-relief planes running
across colorless diamond (right, here seen between crossed polarizers,
field of view ~14 mm). However, most of these phenomena are
accompanied by slight variations in index of refraction, which
might be used as a more precise definition of graining.
Photographs by T. Hainschwang
Figure 8
programs in universities worldwide and by the lack of
visibility of high-quality gemological research. However,
gemology actually has a long history as a discipline, and
some excellent research is being conducted by gemologists.
A NEW SCIENCE, FOR THE FUTURE
OF MINERALOGY
Gemology has its roots in work by the Greek and Roman
naturalists and philosophers. In 315 AD, Theophrastus
described how stones (including gemstones) form. Pliny
(circa 79 AD) had already mentioned identification issues,
particularly regarding green gem materials (smaragdus) and
treated materials (such as treated agates). Centuries later,
around Renaissance times, Pliny was still a reference in the
field. The development of gemology as a modern science
started with Haüy (1817) and his contemporaries. During
the 19th century, many gemological tools were invented,
such as the refractometer and polarizing filters (at the time,
made of gem tourmaline). These two examples of equipment are still fundamental to gemological identification.
REFERENCES
Devouard B, Notari F (2009) The identification of faceted gemstones: From the
naked eye to laboratory techniques.
Elements 5: 163-168
Fritsch E (1992) The Larousse Encyclopedia
of Precious Gems. Translated from
Larousse des Pierres Précieuses by
Bariand P and Poirot J-P, Van Nostrand
Reinhold, New York, 248 pp
Gemology has benefited from input from scientific methods
over many years, even if this was very gradual (see the
“state of the art” by Gramaccioli 1991). However, it is only
in the last ten years that special sessions have been dedicated to gem materials in international conferences, mostly
in the fields of geology and mineralogy (for example, at
the International Mineralogical Association meetings and
the International Geological Congress). Only recently has
gemology become a truly independent branch of science,
with its first ISI journal (Gems & Gemology, accepted in May
2004) and the first scientific conference based on accepting
abstracts after a full peer-review process (Gemological
Research Conference, August 2006, San Diego, California,
USA). A growing number of scientists focus their work on
gemological materials and topics, in laboratories devoted
to well-established disciplines such as mineralogy, geology,
physics, and mathematics. Hence gemology is becoming a
more widely recognized science. It represents one of the
future areas of specialization for students in mineralogy,
geochemistry, and petrology. We would like to believe that
the excitement of working with gems is one of the driving
forces behind the development of gemology—gems are
beautiful, have a rich history, and offer complex challenges
and rewarding research opportunities.
ACKNOWLEDGMENTS
We thank Alice Keller, Rod Ewing, and Thomas Hainschwang,
whose reviews strengthened this article. Also, we wish to
thank past gemologists who contributed to making gemology
a science.
Gübelin E (ed) (1994) World Map of Gem
Deposits. Schweizerische Gemmologische
Gesellschaft/Hugo Buscher, Geneva
Haüy R-J (1817) Traité des caractères physiques
des pierres précieuses pour servir à leur
détermination lorsqu’elles ont été
taillées. Courcier (ed), Paris, 253 pp
Hurlbut CS, Kammerling RC (1991)
Gemology, 2nd edition. John Wiley & Sons,
New York, 336 pp
Nassau K (1980) Gems Made by Man.
Chilton Book Company, Radnor, PA, 364 pp
Rossman GR (2009) The geochemistry
of gems and its relevance to gemology:
Different traces, different prices.
Elements 5: 159-162
Schmetzer K (1983) Eine Untersuchung
der opalisierenden Syntheseprodukte
von Gilson. Zeitschrift der Deutschen
Gemmologischen Gesellschaft 2-3: 107-118
Gauthier J-P, Karampelas S (2009) Pearls
and corals: “Trendy biomineralizations.” Elements 5: 179-180
Jannettaz E, Vanderheym E, Fontenay E,
Coutance A (1881) Diamant et pierres
précieuses. J Rothschild (ed), Paris, 580 pp
Gramaccioli C (1991) Application of mineralogical techniques to gemmology.
European Journal of Mineralogy 3: 703-706
Kane RE (2009) Seeking low-cost perfection: Synthetic gems. Elements 5:
169-174
Shigley JE, Dirlam DM, Laurs BM, Boehm
EW, Bosshart G, Larson WF (2000) Gem
localities of the 1990s. Gems & Gemology
36: 292-335
Groat LA, Laurs BM (2009) Gem formation, production, and exploration: Why
gem deposits are rare and what is being
done to find them. Elements 5: 153-158
Liddicoat RT (1987) Handbook of Gem
Identification. GIA, Santa Monica, CA,
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Shigley JE, McClure SF (2009) Laboratorytreated gemstones. Elements 5: 175-178
J une 2009
Gem Formation, Production, and
Exploration: Why Gem Deposits Are Rare
and What is Being Done to Find Them
Lee A. Groat1 and Brendan M. Laurs2
1811-5209/09/0005-0153$2.50 DOI: 10.2113/gselements.5.3.153
T
he geology of gem deposits is a relatively new area of research focused
on understanding the rare and exceptional geologic conditions that give
rise to gem-quality materials. These conditions may include the availability
of sometimes uncommon major constituents, the presence of adequate
chromophores, limited concentrations of undesirable elements, open space,
an environment conducive to forming crystals of sufficient size and transparency,
and a favorable environment for mining. Future research should aid exploration,
which until recently has been nonsystematic and nonexistent for many gem
minerals, with diamond as the notable exception.
Keywords : gems, diamond, emerald, sapphire, ruby, geochemistry, exploration
INTRODUCTION
Gems (defined by Fritsch and Rondeau 2009 this issue)
have been prized for thousands of years for their color,
luster, transparency, durability, and high value-to-volume
ratio. The value of a gem depends primarily on esthetic
and durability factors, but rarity is also significant. Some
gems are fashioned from minerals that are quite rare in
nature (e.g. benitoite, taaffeite, and brazilianite), while many
others are produced from common minerals (e.g. quartz,
feldspar, and garnet). Features that make a gemstone valuable, such as color, size, and transparency, can be extremely
elusive even if the mineral itself is common. When a
common mineral has certain features, such as an attractive
color, a relatively large size, and a high degree of transparency, it can be used as a gemstone (e.g. amethyst—the
purple variety of quartz, SiO2). It is not the mineral itself
that makes a gemstone; it is the characteristics of a specific
sample. For example, a corundum crystal is not a gemstone
(e.g. ruby, sapphire) unless it formed in an environment that
allowed it to attain a suitable size, transparency, and color.
Gem deposits are rare because the geologic conditions
necessary for the formation of gem-quality materials are
rarely attained. These conditions include some or all of the
following: (1) availability of major constituents, which in
some cases are uncommon in nature; (2) presence of adequate
chromophores (elements responsible for color in minerals),
which can be rare in certain environments; (3) limited
concentrations of undesirable elements, which may be
common either in nature or in a specific geologic environment (such elements can either impart an “off” color or
1 Department of Earth and Ocean Sciences
University of British Columbia
Vancouver, BC V6T 1Z4, Canada
E-mail: [email protected]
2 Gemological Institute of America (GIA)
5345 Armada Drive, Carlsbad, California 92008, USA
E-mail: [email protected]
E lements , V ol . 5,
pp.
153–158
impede crystal formation); (4)
open space for crystals to grow
unimpeded, which is rare in most
geologic environments; (5) an environment to form crystals of sufficient size and transparency; and (6)
a favorable environment for
mining. These exceptional requirements also make gem deposits
fascinating for scientific study. This
fascination, combined with economic
considerations, has stimulated an
increasing interest in the geology
of gem deposits in recent years (e.g.
Kievlenko 2003; Groat 2007).
GEM FORMATION
Ingredients
Most gems are minerals and therefore have a definite (but
not fixed) chemical composition. Examples include diamond
(C), ruby (red gem corundum, Al2O3), sapphire (any other
color of gem corundum), and emerald (green chromium/
vanadium-bearing gem beryl, Be3Al2Si6O18). One notable
exception is jade, a rock composed of either microcrystalline
jadeite (NaAlSi2O6), referred to as jadeite jade, or tremoliteactinolite [Ca2(Mg,Fe)5Si8O22(OH)2], referred to as nephrite.
The formation of most gems requires adequate concentrations of essential constituents (or essential structural
components; London 2008). For example, carbon is a trace
element in the mantle, and the formation of gem-quality
diamonds requires local enrichment of carbon (Stachel
2007). Most gems, diamond being an exception, also
require that their essential elements be brought into contact
with appropriate concentrations of a chromophore, often
a transition metal [e.g. chromium in ruby or vanadium in
tanzanite (violetish blue gem zoisite, Ca 2Al3Si3O12OH) and
tsavorite (green gem grossular, Ca3Al2Si3O12)].
A good example of the requirement for a major element
and a chromophore is emerald. Beryl is a relatively rare
mineral because there is very little beryllium in the upper
continental crust (2.1 ppm; Rudnick and Gao 2003), where
it tends to be concentrated after prolonged fractional crystallization of a magma (London 2008), in granites, pegmatites, and their metamorphic equivalents. Chromium and
vanadium are more common (92 and 97 ppm, respectively;
Rudnick and Gao 2003) but are concentrated in different
rocks: chromium in dunite, peridotite, basalt, and their
metamorphic equivalents, and vanadium in organic- and
iron-rich sediments and their metamorphic equivalents.
These are typically not found near beryllium-rich environments. Dynamic geologic and geochemical conditions are
required for beryllium and chromium or vanadium to
meet. In the classic model, beryllium-bearing pegmatites
153
J une 2009
interact with chromium-bearing ultramafic or mafic rocks.
However, in the black shale–hosted Colombian deposits,
there is no evidence of magmatism, and it has been demonstrated that hydrothermal circulation processes associated
with tectonic activity were sufficient to form emerald (e.g.
Ottaway et al. 1994; Cheilletz and Giuliani 1996; Branquet
et al. 1999; see Fig. 1). In addition, some researchers have
suggested that regional metamorphism and tectonometamorphic processes, such as shear zone formation, have
played a significant role in certain emerald deposits (notably
Habachtal in Austria, Leydsdorp in South Africa, and
Franqueira in Spain; Grundmann and Morteani 1989; Nwe
and Morteani 1993; Franz et al. 1996).
It is interesting to note that chromium is the chromophore
in both ruby and (most) emerald. In ruby, the details of
the atomic environment and local charges around the chromium ion result in a strong interaction, equivalent to a
small “cage” around the ion. This induces absorption at
high energy, and hence most of the transmission is at low
energy, in the red part of the visible spectrum. The opposite
occurs in emerald, in which the local environment is more
relaxed, resulting in a looser “cage” around the chromium
ion. The absorption is at lower energy, which results in the
well-known emerald-green color (Burns 1993).
The formation of a gem deposit requires not only the presence of sometimes rare constituents, but also the exclusion
of undesirable elements. For example, corundum will form
only in the relative absence of silica, because in the presence of silica, aluminum is preferentially incorporated into
aluminosilicate minerals such as feldspars and micas.
Certain chromophores, such as iron, can hinder the forma-
tion of attractive, economically important gems by creating
undesirable colors in normal-sized facetable gems (e.g.
black in tourmaline, over-dark green in emerald, brownish
overtones in ruby).
The Recipe
Gem deposits also require specific thermobarometric conditions favorable for the crystallization and stability of the
specific mineral. For example, “Clifford’s Rule” formulates
the close association between diamondiferous kimberlite
and Archean cratons. Deep (up to ~200 km), relatively cool
lithospheric roots are believed to cause the graphite–
diamond transition to rise beneath cratons. The region
where the lithospheric mantle reaches into the diamond
stability field corresponds to a window of opportunity
where diamond may form and reside (see, for example,
Kirkley et al. 1991; Stachel et al. 2005). The diamonds are
later brought to the surface in rapidly ascending ultramafic
magmas, which commonly solidify as kimberlite diatremes
or “pipes,” or as small volcanic dikes and sills. Recent
research suggests that diamonds precipitate from oxidized
(i.e. carbonate-bearing) fluids that could be related to
devolatilization of subducting oceanic slabs (Stachel 2007),
and that they form at specific times in the Earth’s history
that can be correlated to major tectonic events in the lithosphere (e.g. Cartigny 2005).
In some cases, little is known about the thermobarometric
conditions required for gem formation. For example,
corundum occurs in magmatic, metamorphic, and hydrothermal environments. In magmatic deposits, it occurs as
xenocrysts or phenocrysts in alkali basalt, lamprophyre,
and syenite. In metamorphic deposits, it is hosted by
marble, mafic and ultramafic rocks, granulite, cordieritite,
gneiss (Fig. 2), migmatite, desilicated pegmatites, skarns,
and shear-related deposits (e.g. Garnier et al. 2004; Simonet
et al. 2008). Magmatic corundum is generally thought to
form in the lower crust or upper mantle, but a variety of
models have been proposed to explain the particular conditions and geology of the crystallization environment (e.g.
Giuliani et al. 2007; Simonet et al. 2008). Metamorphic
corundum crystallizes at high temperatures and high to
moderate pressures. However, as pointed out by Giuliani
et al. (2007), there exist few data on primary corundum
deposits—that is, where corundum is hosted by a parental
rock—and numerous questions remain. For example,
marble is depleted in silica and aluminum, and to form
corundum in such an environment, a fluid phase seems
necessary. However, aluminum is usually considered to be
an immobile element, and the fluid phase would have to
infiltrate the marble, which in general would have few
fractures and low porosity.
Growth Conditions
Gems need room to grow and thus are often found in
cavities or “pockets.” For example, in the final stages of
crystallization of complex pegmatites (zoned granitic
pegmatites with superimposed areas of metasomatic alteration or replacement zones), volatile-rich fluids may exsolve
and produce cavities lined with beautiful gem-quality crystals, most commonly beryl, topaz [Al 2 SiO4 (F,OH) 2 ], and
tourmaline (London 2008). The pockets tend to be centrally
located within and along the margins of the core zone.
Gem-bearing cavities also occur in hydrothermal veins and
in volcanic rocks (gas pockets).
Emerald from the Coscuez mine, Boyacá, Colombia.
The crystal is 1.3 cm high. Sample courtesy of
Mel Gortatowski ; photograph © Jeff Scovil
Figure 1
E lements
In some cases, gem crystals occur in solid rock and open
space is not critical. The best example is diamond in ultramafic rock (usually kimberlite). Emerald can occur in
schists as a result of metasomatism. Tsavorite rarely occurs
as well-formed crystals, but instead forms rounded “potato”
154
J une 2009
nodules that are typically fractured. Peridot [olive-green
gem olivine, (Mg,Fe) 2SiO4] can form crystal aggregates in
ultramafic rocks. In eastern Zambia, rhodolite [rose-pink
to red pyrope, (Mg,Fe) 3Al2 (SiO4) 3] forms nodular crystals
up to 10 cm in diameter in plagioclase segregation veins
in mafic granulite (Seifert and Vrana 2003). Nodules of
tsavorite, peridot or rhodolite may occasionally contain
fragments of gem-quality material. Other examples of gem
minerals for which open space is not critical include zoisite
(tanzanite), cordierite (iolite), corundum, spinel, and zircon.
Size is important in that the rough material must be large
enough to permit faceting or carving. For example,
cordierite can occur in abundance in Al-rich metamorphic
rocks, but the grain size is generally too small for gem use.
Only in exceptional cases does cordierite form crystals of
sufficient size and transparency to qualify as gems. In most
cases transparency is also an issue; for example, beryl crystals can grow to huge size in pegmatites, but in general
these large crystals are not transparent. Gems must also
be preserved from mechanical fracturing, chemical etching,
metamorphism, and other postgrowth damage. Olivine
can be a common mineral in mafic and ultramafic rocks,
yet peridot is relatively rare in crustal rocks because, in the
presence of water, it is highly susceptible to chemical
attack. In a process analogous to diamond formation in
kimberlite, peridot can form at depth in the mantle and
be carried to the surface relatively quickly in alkali basalt,
minimizing the opportunity for chemical attack.
Ruby and pink sapphire from Greenland, together with
gneissic host rock. The largest cut stone weighs 5.69 ct.
Samples courtesy of True Nor th Gems Inc.; photograph © Robert Weldon /
Gemological Institute of A merica
Figure 2
E lements
Preservation from extensive fracturing can be seen in gems
that grow in cavities (e.g. hydrothermal veins and pegmatites) as opposed to within solid rock; this is particularly
evident in emeralds from veins as opposed to those from
schist-type deposits. At the Stewart mine in California,
gem-forming fluids followed fractures, resulting in the
formation of near-vertical “chimneys” with pockets
containing pristine gem crystals that precipitated from
late-stage volatile fluids (J. Blue Sheppard, pers. commun.
2004; Fig. 3). However, pegmatite gems may also experience fracturing (probably from pocket-rupture events), as
well as etching and, particularly, chemical reequilibration.
Some pegmatites from Brazil contain partly dissolved beryl
crystals, giving rise to spectacular etched specimens but
fewer gems. Gem beryl crystals from the Ukraine also often
show the effects of etching.
Closer to the Surface
Some gem deposits result from shallow subsurface processes.
Opal (SiO2.nH2O), for example, may be deposited by hot
springs at shallow depths, by meteoric waters, or by lowtemperature hypogene solutions (Gaillou et al. 2008). It is
most often found lining and filling cavities in rocks, but may
also replace fossils. The formation of the valuable play-ofcolor implies very stable conditions during the slow accumulation of silica spheres in a regular, light-diffracting,
three-dimensional network. Curiously, this gem is found in
Blue Sheppard next to a “chimney” in the Stewart
mine, Pala, California. The chimneys are composed of
sodic plagioclase (albite–oligoclase), black tourmaline, and muscovite.
An excavated gem pocket can be seen at the base of the chimney.
Photograph © Brendan L aurs /Gemological Institute of A merica
155
Figure 3
J une 2009
two contrasting geologic environments: volcanic rocks such
as rhyolitic tuff (mostly poorly crystallized opal-CT) and
sedimentary rocks within basins (mostly amorphous opal-A).
Turquoise [CuAl6 (PO4)4 (OH) 8 ·4H2O] is a secondary mineral
usually found in the form of small veins and stringers
traversing more or less decomposed volcanic rocks
(“porphyry copper”) in arid regions. Green malachite
[Cu 2CO3 (OH) 2 ] and blue azurite [Cu3 (CO3) 2 (OH) 2 ] (Fig. 4)
are widely distributed supergene copper minerals found,
for example, in the oxidized portions of copper deposits
associated with limestones.
It is important to recognize that most gems, like other
commodities, are subject to the forces of supply and
demand. Although it is difficult to obtain accurate figures
for many of the gem varieties, it looks as though demand
is at least staying constant while traditional sources are
becoming depleted. For example, peak world diamond
production may soon be passed, and it is speculated that
the Colombian emerald mines are becoming exhausted,
whereas commercial quantities of tanzanite are (so far)
found at only one place in the world.
Many gems come from poor countries, where the discovery
of a new deposit could lead to a major change, for better
or worse, in the standard of living in the immediate area.
For example, the discovery of diamonds in 1967 transformed Botswana from one of the world’s poorest countries
into an upper-middle-income economy. However, poverty
rates in Botswana are high, and the distribution of income
and resources is extremely unequal. Some countries have
seen very little exploration, especially for colored gems
(Canada, with its huge land mass and low population
density, would seem to be a logical place to look).
Irrespective of country, the stability of the political regime
and security of mineral tenure are important issues. In
some places, smuggling is a major problem, and the gem
trade has been used to fund civil wars, rebellions, and
terrorist activities. A foolproof technology to track individual stones seems desirable.
GEM EXPLORATION
Cabochons consisting of intergrown blue azurite and
green malachite, from the Milpillas mine in Sonora, Mexico.
The larger stone measures 4.9 by 3.5 cm. Samples courtesy of Palagems.
com ; photograph © Robert Weldon /Gemological Institute of America
Figure 4
It is important to note as well that many gems occur in
secondary deposits of sedimentary origin. These form by
the accumulation, in basins of variable extent, of material
eroded from primary deposits. This material is primarily
transported by rivers. Gems found in such placer deposits
must be dense enough to be concentrated by gravity and
durable enough to survive transport. Because cracked and
weathered specimens are more likely to be destroyed during
transport and cleaner pieces more likely to survive, there
tends to be a higher ratio of gem to non-gem material in
alluvial deposits compared to primary sources. Typical
examples include some diamond and corundum deposits,
in which the proportion of gem-quality crystals increases
with distance from the source, the more fractured material
having been progressively destroyed along the way.
GEM PRODUCTION
Because many gems are produced from relatively small,
low-cost operations in remote regions of developing countries, it is difficult to obtain accurate statistics regarding
production and value (Yager et al. 2008). However, diamond
production in 2007 was an estimated 173 million carats
(worth US$13.9 billion) from some 20 countries, with
Botswana, Russia, Canada, South Africa, and Angola being
the top five producers by value (Read 2008). In 2001, the
world colored-gem trade was estimated to be worth about
US$6 billion per year (Beard 2001).
E lements
Exploration protocols for gems range from highly developed (diamonds) to unsystematic or nonexistent (most
other gem materials). Techniques used for diamond exploration include heavy mineral sampling and processing
(often using dense-media separators), indicator mineral
chemistry, and geophysics. These techniques are becoming
increasingly sophisticated as diamond exploration activities evolve. In Canada, it is also necessary to consider
regional advance and retreat patterns of glacial ice. The
indicator mineral technique is based on the recognition of
distinctive minerals in glacial sediments (chromiumpyrope, chromium-diopside, magnesium-ilmenite, and
olivine) associated with the diamond source rocks, and
then tracing them back to the source (see http://atlas.
nrcan.gc.ca/site/english/maps/economic/diamondexploration). A large fraction of most diamond exploration
budgets is allocated to high-resolution geophysical techniques operating from a variety of platforms. Most notably,
Shore Gold Inc. and Newmont Mining have used airborne
magnetic surveys to delineate kimberlites buried under
100 m of glacial overburden in central Saskatchewan, and
De Beers has operated a gravity survey system from an
airship (Read 2008).
Prospecting guides exist for some of the other gem materials, for example, emerald (see Groat et al. 2008). These
guides point out that mineral associations are important.
For example, chrysoberyl and phenakite are obvious indicator minerals for “metamorphic-type” emerald occurrences. Geochemistry has proven to be useful in Colombia.
Escobar (1978) studied the geology and geochemistry of
the Gachalá area and found that enrichment of Na and
depletion of Li, K, Be, and Mo in the host rocks were good
indicators for locating mineralized areas. Beus (1979)
presented the results of a United Nations–sponsored
geochemical survey of the streams draining emerald
deposits in the Chivor and Muzo areas of Colombia. The
spatial distribution of areas with emerald mineralization
was linked, on a regional scale, to intersections of northnortheast- and northwest-trending fault zones. The black
156
J une 2009
shales in tectonic blocks containing emerald mineralization were found to be enriched in CO2, Ca, Mg, Mn, and
Na and depleted in K, Si, and Al (Beus 1979). The results
of this study were tested with a stream-sediment sampling
program in the Muzo area, and samples collected from
emerald-bearing tectonic blocks had anomalously low K/
Na ratios. Subsequently it was discovered that the Na
content of the sediments was the best indicator of the
mineralized zones in the drainage basins. Several new
emerald occurrences were discovered by United Nations
teams using the results of this study. Also, Ringsrud (1986)
reported that Colombian geologists were analyzing soil
samples collected from altered tectonic blocks for Li, Na,
and Pb to delineate emerald mineralization. Cheilletz et
al. (1994) showed that the Be content of black shales outside
of the leached mineralized areas ranges from 3.4 to 4 ppm.
Beryllium concentrations in the leached areas were found
to range from 0.1 to 3.0 ppm (Beus 1979). Structural
geology is also important for emerald exploration in
Colombia (Branquet et al. 1999). In the western zone (Muzo
and Coscuez areas), deposits are linked by tear faults and
associated thrusts.
Other publications available include exploration guidelines
for environments favorable for gemstone formation. For
example, Simonet and Okundi (2003) described and evaluated prospecting methods adapted to gemstone prospecting, including geological mapping, systematic eluvial
test pitting, geophysical and geochemical prospecting, and
remote sensing. They also presented a case study from the
Kisoli rhodolite, tourmaline, and ruby prospect in southern
Kenya, in which resistivity mapping, radiospectroscopy,
and soil geochemistry helped to identify geological conditions favorable for gem deposits. In another example,
Turner and Groat (2007) listed criteria for distinguishing
granites that could be parental to highly evolved granitic
pegmatites in the Canadian Cordillera; these include size
(smaller than 30 km2 ), affinity (S-type), age (mid-Cretaceous), geochemistry (peraluminous; enrichment in largeion-lithophile and high-field-strength elements; initial
strontium isotope 87Sr/ 86Sr ratio greater than 0.7100; large
negative neodymium anomaly), and mineralogy (peraluminous, e.g. containing both muscovite and biotite). A
survey of geophysical techniques used in gem exploration
was published by Cook (1997).
A new interest in mining and exploring for colored gem
deposits appears to be dawning, in general by smaller
companies of which an increasing number are listed on
world stock exchanges, in particular the TSX Venture and
AIM (Alternative Investment Market) exchanges. In addition, there has recently been a trend toward vertical integration, whereby a single company conducts exploration,
mining, beneficiation, and marketing. One example is
Pallinghurst Resources, which in June 2008 announced a
reverse takeover of Gemfields Resources Plc by one of its
portfolio companies, Rox Limited (see www.pallinghurst.
com). Rox contributed a 75% interest in the Kagem mine
in Zambia, Africa’s largest emerald mine, and an option to
acquire a portfolio of licenses for gemstone exploration in
Madagascar. Pallinghurst also announced that Fabergé
Limited, another portfolio company, has granted Gemfields
an option to acquire a worldwide and exclusive 15-year
license to use the Fabergé brand name for its better-quality
gemstones (excluding diamonds). Pallinghurst and
Gemfields claim that these transactions are key steps in
their objective to create a leading colored-gemstone
company and to pursue consolidation and vertical integration in the sector. Other examples include advanced exploration projects by True North Gems Inc. in Canada (for
emerald and sapphire; see Fig. 5) and Greenland (for ruby;
E lements
Brad Wilson using a diamond-bladed chainsaw to
extract emerald-bearing rock from the Ghost Lake
occurrence in northwestern Ontario, Canada
Figure 5
Fig. 2), and Cluff Resources Pacific NL, which has been
producing pink sapphire and ruby from placer deposits in
New South Wales, Australia.
see
CONCLUSIONS
Many questions (and therefore opportunities for research)
remain regarding the geology of gem deposits. For example,
researchers are only now beginning to understand the
genesis of marble-hosted ruby and sapphire deposits
(Giuliani et al. 2007). As pointed out by Groat et al. (2008),
there is a paucity of modern electron microprobe and trace
element composition data for emerald, and a comprehensive library of such compositions would be a valuable asset
for future researchers. In addition, the role of metamorphism in the formation of some emerald deposits is controversial (see Zwaan 2006) and, thus, worthy of additional
study. There is also a need for an unambiguous classification scheme that would aid in our understanding of the
mechanisms and conditions leading to the formation of
emerald deposits (Zwaan 2006).
However, understanding how gem deposits form is of more
than academic interest because it can provide guidelines
for exploration. Because of this, the geology of gemstones
is developing into a specialization within economic
geology. Although existing exploration guidelines are
starting to generate new discoveries, most new mines are
found by chance, not by design, and further development
of exploration guidelines is desirable for many gem materials. This, combined with new technologies, should ensure
a healthy supply of gems for the future. In this sense, not
only diamonds, but all gems “are forever.”
ACKNOWLEDGMENTS
Funding was provided by the Natural Sciences and
Engineering Research Council of Canada in the form of a
Discovery Grant to LAG. The authors thank Jean-Jacques
Guillou, Mackenzie Parker, Cédric Simonet, Bradley S. Wilson,
an anonymous reviewer, and Guest Editors Emmanuel
Fritsch and Benjamin Rondeau for their constructive criticism of earlier versions of the manuscript. 157
J une 2009
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E lements
158
J une 2009
The Geochemistry of Gems
and Its Relevance to Gemology:
Different Traces, Different Prices
George R. Rossman1
1811-5209/09/0005-0159$2.50 DOI: 10.2113/gselements.5.3.159
I
n colored gems, minor and trace chemical components commonly
determine the difference between a common mineral specimen and
a gemstone. Also, these components are often responsible for the
color, and may provide a “fingerprint” for determining the provenance
of the gemstone. The minor elements that are incorporated will depend
on local geologic conditions such as temperature, redox conditions, and,
particularly, chemistry.
Keywords : gemstone, provenance, color, geochemistry
COLOR IN GEMSTONES
Metal ions from the first row of transition elements in the
periodic table, especially Ti, V, Cr, Mn, Fe, and Cu, are the
most important causes of color in oxide and silicate
gemstones. V3+, Cr3+, Mn3+, and Cu 2+ can produce strong
coloration when present at concentrations of tenths of a
weight percent. Color comes from electronic transitions
involving only the electrons in the d-orbitals (referred to
as ligand-field transitions or crystal-field transitions). When
present by themselves, Fe2+, Fe3+, and Mn2+ typically require
higher concentrations to cause significant color. Intervalence
charge transfer (IVCT) interactions, which involve an
exchange of an electron between two cations with different
valences (for example, between Fe2+ and Fe3+ or between
Fe 2+ and Ti4+) are a major source of color in gems and
require only a small amount of the interacting couple to
produce intense color. In some systems, charge transfer
from oxygen to the metal ion also contributes to the color.
Green color can also occur in
andradite garnet, Ca 3Fe 2 (SiO 4 ) 3.
Andradite is pale yellow-green when
it has exactly the end member
composition, but commonly, minor
amounts of Ti4+ coupled with Fe2+
turn andradite to brown or black.
A beautiful green variety of andradite occurs when minor amounts
of Cr3+ enter the garnet (Mattice
1998). These stones, known as the
variety demantoid, are highly
valued (Fig. 1b).
The stoichiometric components of garnets also depend on
the geologic setting. In lithium pegmatites, minerals that
crystallize late in the formation of the gem pockets in the
pegmatites can be nearly devoid of iron. In this setting,
nearly pure end member spessartine garnet, Mn3Al2 (SiO4) 3,
can occur. This garnet has a beautiful orange color due to
Mn2+ in a cation site of eight-coordination (Fig. 2). If the
garnet grows while some iron is still present in the pegmatitic fluids, the color becomes a much less valuable brown-orange
due to solid solution with the almandine end member,
Fe3Al2 (SiO4) 3.
A
Garnets
Good examples of the compositional dependence of color
are provided by the garnet group. When grossular garnet,
Ca3Al2 (SiO4) 3, is composed of just the end member components, it is colorless. Ca 2+, Al3+, Si4+, and O2- ions do not
absorb light in the range of the visible spectrum. However,
low concentrations of minor elements can dramatically
modify the color. Small amounts of V3+ with some Cr3+
turn grossular into the green tsavorite variety (Fig. 1a).
Spectacular examples of these garnets occur in marble
seams in graphitic gneisses of the Mozambique belt in
northeastern Tanzania and southeastern Kenya. There,
metamorphic fluids were able to mobilize traces of vanadium and chromium from the host rock and incorporate
them in the grossular garnets. The unusual beauty of these
garnets was recognized after their discovery in 1967 and
they were given the trade name tsavorite, in honor of the
nearby Tsavo National Park in Kenya (Bancroft 1984).
B
(A) The tsavorite variety of grossular garnet owes its color
to the substitution in the Al site of about a percent level
of
accompanied by a lesser amount of Cr3+. This stone
weighs 7.4 carats. (B) The color of the demantoid variety of andradite
is due to a minor amount of Cr3+ but is somewhat modified by the
presence of the stoichiometric constituent Fe3+. This highly valued
variety of andradite has classically come from the southern Ural
Mountains of Russia. Photos : Wimon Manorotkul, Palagems.com
Figure 1
V3+ usually
1 Division of Geological and Planetary Sciences
California Institute of Technology
Pasadena, CA 91125-2500, USA
E-mail: [email protected]
E lements , V ol . 5,
pp.
159–162
159
J une 2009
PROVENANCE OF GEMS
Minor and Trace Elements
Over time, gems from certain localities have been recognized as having greater beauty, and thus greater value. Even
as new sources of gems are located, gems from the classic
localities may still be perceived to have a higher value than
more recently discovered stones of similar color and quality.
The geographical origin of gems, in a general sense, is
becoming an important commercial factor. More value is
ascribed to particular deposits of gems compared to others
with similar geology.
Minor and trace elements are often different or incorporated
differently in gems of the same species but from different
localities. Thus, they may provide a readily available tool for
determining the locality of origin of gems. The following
examples illustrate this concept.
One question that must be addressed is what can be done
with a faceted stone to determine its locality of origin. The
need to avoid visually destructive analytical methods
restricts the use of many standard geochemical methods
and presents demanding analytical challenges. A variety
of tools are now available, including minimally or
non­destructive chemical analysis for major and trace
elements, luminescence, and isotopic analysis. Other
avenues of investigation, such as inclusions and growth
features, are discussed in Fritsch and Rondeau (2009 this
issue) and Devouard and Notari (2009 this issue).
Tourmaline
Most gem tourmalines owe their color to Fe2+ (most blue
tourmalines), Fe2+ plus Fe2+ –Ti4+ IVCT (green), Mn3+ (pink),
Mn2+ –Ti4+ IVCT (yellow), or a combination of these factors
(Fig. 3). At a few localities, such as in Kenya and Tanzania, Cr3+
and v3+ are the minor components responsible for the color.
In 1988, a new find of gem-quality elbaite with unusually
saturated shades of green and blue was made in the
Brazilian state of Paraíba. The unusual blue color comes
from the copper content, which can range up to 1.7 wt%
CuO (Rossman et al. 1991). The stones became an instant
success in the commercial market (Fig. 4, inset). Later, tourmalines were found in Nigeria and Mozambique that also
contained copper and had blue colors approaching those
of the tourmaline gems from Paraíba. The question was
raised about the possibility of distinguishing the provenance
of copper-containing tourmalines once they had been
faceted and entered the market.
Quantitative laser ablation–inductively coupled plasma–
mass spectrometry (LA–ICP–MS) analysis can be used to
differentiate tourmalines from the various localities by
comparing concentrations or proportions of selected minor
and trace elements such as Cu, Mn, Ga, Pb, Be, Mg, and Bi.
For example, the Brazilian stones generally have more Mg,
Zn, Bi, and Sb, while the Nigerian stones generally contain
elevated levels of Ga and Pb (Abduriyim et al. 2006). By
comparing the relative proportions of Bi, Pb, and Ga in such
tourmalines, one can, in most cases, distinguish between the
three main geographical provenances (Fig. 4). However, there
is still a small overlap between the compositions of tourmalines from Mozambique and Brazil (Krzemnicki 2007).
Corundum
For many years, rubies from the Mogok region of Burma
were considered the finest in the world and commanded
a high price (Hughes 1997). Beginning in the early 1990s,
rubies from a different source in Burma appeared in markets
in Bangkok. The Möng-Hsu rubies generally are unsaleable
as mined. They usually must be heated, often to high
temperatures, to remove a naturally occurring dark blue
color that arises from a combination of Fe2+ –Ti4+ and Fe2+ –
Fe3+ IVCT in the core of the stones. Heating oxidizes the
Fe2+ to Fe3+, which disrupts the IVCT couple. Furthermore,
the heating of rubies from Möng-Hsu introduces flux into
cracks in the stones (Peretti et al. 1995; Emmett 1999).
Although beautiful, the rubies from Möng-Hsu are generally valued less than rubies from Mogok because they have
been treated to enhance their appearance (Drucker 1999).
A crystal of orange spessartine and a faceted gem from
the Little Three mine near Ramona, San Diego County,
California. The orange color is due to Mn2+ in the eight-coordinated
cation site of the garnet. Photo: Wimon Manorotkul, www.palagems.com
Figure 2
A suite of tourmalines illustrating the tremendous variety
of colors displayed by this mineral group. All the gems
in this figure probably belong to the tourmaline species elbaite. End
member elbaite’s ideal composition is Na(Li1.5Al1.5)Al6(BO3)3Si6O18 (OH)4,
a species that would be devoid of color if it were exactly the ideal
composition. The gems in this photo are colored by traces of iron,
manganese, and titanium. Photo: Wimon Manorotkul, www.palagems.com
Figure 3
E lements
Thus it would be useful to be able to distinguish rubies
from different localities. Apart from specific microscopic
features, it has been shown that rubies from the Mogok
and Möng-Hsu localities can be differentiated on the basis
of their Ti/V ratio (Muhlmeister et al. 1998; Mittermayr et
al. 2008) as determined using X-ray fluorescence (XRF) or
LA–ICP–MS. In other examples, key elements, such as V,
Ti, Ga, and Fe, have been used to separate rubies from
Vietnam/Burma versus Thailand or Tanzania. For a more
general distinction of ruby localities, the ratios of Fe, Ga,
and Cr have proven useful (Rankin et al. 2003; Peretti
2008; Schwarz et al. 2008). Likewise, the source of blue
sapphires can be determined using the trace element ratios
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J une 2009
of Zn, Sn, Ba, Ta, and Pb as determined by LA–ICP–MS
analysis of element concentrations down to levels
approaching ppb (Guillong and Günther 2001; Rankin et
al. 2003; Abduriyim and Kitawaki 2006a).
Isotopic Methods
The provenance of gems has always been important to
some degree. However, now that provenance has increased
in importance for commercial reasons, the tools to determine origin have been refined. Chemical composition, inclusions, growth features, luminescence, and trace elements
may all have a role in the determination of provenance.
While stable isotopes have proven highly useful in
geochemistry for studying the geological history of rocks
and minerals, they have, to date, found little practical
application in the determination of the provenance of
gemstones. In principle, isotopes should provide information about the origin of gems, but the cost, time required,
and destructive nature of these tests have, until now,
prevented isotopic methods from gaining wide application
in gemology. A few examples demonstrate the utility of
isotopic methods when applied to gem minerals.
Emerald
Emerald is a green variety of beryl, Be 3Al 2 Si6O18, that
contains Cr3+ and, occasionally, some V3+ as the chromophore.
It forms from hydrothermal fluids. The isotopic composition of these fluids varies with locality (Giuliani et al. 1998;
Zwaan et al. 2004). In an elegant study, Giuliani et al.
(2000) used the isotopic composition of oxygen in emerald
to trace international trade routes since antiquity (Fig. 5).
wide use in commercial gem laboratories, but holds much
promise for the future. As is the case with many analytical
methods, the overlapping ranges of oxygen isotope ratios,
especially for the classical or commercially important
deposits such as Mogok, Kashmir, Sri Lanka, and Madagascar,
mean that no single analytical method will provide the
answers to all problems of provenance.
SYNTHETIC CRYSTALS
Many of the same analytical methods used to differentiate
the geographic or geologic source of a gem can also be
applied to distinguish synthetic from natural stones. Such
distinctions will become increasingly important as the
quality of synthetic materials rises to nearly match that of
their natural counterparts.
Synthetic Amethyst
Hydrogen is an important trace element in many natural
minerals. It is a common charge-balancing cation (in the
form of an OH group). Its mode of incorporation can vary
depending on the geologic conditions of formation of the
host crystal. The intensity and shape of absorption bands
in the OH region of the electromagnetic spectrum provide
a test for synthetic amethyst. A band at 3595 cm-1 is present
in the infrared spectrum of all natural amethysts but only
rarely in synthetic ones. If present in synthetic amethyst,
its full width at half maximum (FWHM) is about 7 cm-1,
whereas it is about 3 cm-1 in all natural samples. This
absorption band difference provides a method to separate
natural from synthetic amethysts (Karampelas et al. 2005).
Synthetic Ruby
Corundum
Because both ruby and sapphire occupy an important place
in the gem market, the origin of corundum gems is a matter
of interest. In addition to the use of chemical element
ratios, as discussed above, to distinguish among localities,
certain classes of corundum show large isotopic differences
between different localities (Yui et al. 2003; Giuliani et al.
2005). Oxygen isotopes in carbonate-hosted corundum
show wide variations, whereas oxygen isotopes in mantlederived corundum vary much less. Because of the time
required for isotope analysis, its expense, and the destructive nature of the technique, the approach has not gained
Minor and trace components commonly found in nature
can be lacking in some synthetic gems. Such differences
can be detected by some of the same testing methods previ-
The oxygen isotope composition of emeralds varies
among important gem-producing regions of historical
importance. The colored bands indicate the range of composition at
each locality, and the white rectangles indicate the composition of
the ancient emeralds studied by Giuliani et al. (2000). 1: Gallo-Roman
earring; 2: Holy Crown of France; 3: Haüy’s emeralds; 4: Spanish
galleon wreck; 5: “old mine” emeralds. The isotopic variations allowed
these authors to trace the flow of emeralds in world commerce from
antiquity to the late 18th century. Graph modified from Giuliani et al. (2000)
Figure 5
A plot of the relative proportions of Bi, Pb, and Ga, all
present as trace elements in Cu-containing tourmalines
(inset), can in most cases distinguish the provenance of such
tourmalines: Nigeria, Mozambique, or Brazil. These data were
obtained using LA–ICP–MS. Graph modified from Mickael Krzemnicki
(2007); Photo (inset): Wimon Manorotkul, www.palagems.com
Figure 4
E lements
161
J une 2009
ously discussed. For example, for several years, synthetic
ruby was made from purified aluminum oxide from which
most of the naturally occurring gallium had been removed
in the industrial purification process. Thus, natural rubies
were readily distinguished by the presence of trace concentrations of gallium. However, soon after the gallium test
became widely known, gallium began to appear in some
synthetic stones.
Synthetic Emerald
For some time, a minor absorption band at 2293 cm-1 in
the infrared spectrum of natural emeralds was found to be
absent in the spectrum of synthetic emeralds and could
therefore be used as a test to distinguish between natural
and synthetic stones. However, such tests are not always
long lasting. In the case of emeralds, Russian hydrothermal
synthetic emeralds now contain the 2293 cm-1 band (DurocDanner 2006). Bands caused by water trapped in the c-axis
channels of beryl are present in natural emeralds and aquamarines (the blue variety of beryl) but are absent in fluxgrown synthetic emeralds. Fortunately, other methods for
distinguishing natural from synthetic emeralds are available,
and these are based on trace element analysis using
methods such as XRF and particle-induced X-ray emission
(PIXE) (Yu et al. 2000).
REFERENCES
Abduriyim A, Kitawaki H (2006a)
Determination of the origin of blue
sapphire using Laser Ablation Inductively
Coupled Plasma Mass Spectrometry
(LA-ICP-MS). The Journal of Gemmology
30: 23-36
Abduriyim A, Kitawaki H (2006b)
Applications of laser ablation–inductively
coupled plasma–mass spectrometry
(LA-ICP-MS) to gemology. Gems &
Gemology 42: 98-118
Abduriyim A, Kitawaki H, Furuya M,
Schwarz D (2006): “Paraíba”-type copperbearing tourmaline from Brazil, Nigeria,
and Mozambique: Chemical fingerprinting
by LA-ICP-MS. Gems & Gemology 42: 4-21
Bancroft P (1984) Tsavorite. In: Gem and
Crystal Treasures. Western Enterprises/
Mineralogical Record, Fallbrook, CA, pp
298-302. Available online at: http://
palagems.com/tsavorite_bancroft.htm
Devouard B, Notari F (2009) The identification of faceted gemstones: From the
naked eye to laboratory techniques.
Elements 5: 163-168
Drucker RB (1999) Ruby: Why the source
affects the price. www.jckonline.com/
article/CA635628.html
Duroc-Danner JM (2006) The identification
value of the 2293 cm-1 infrared absorption
band in natural and hydrothermal
synthetic emeralds. The Journal of
Gemmology 30: 75-82
Emmett JL (1999) Fluxes and the heat
treatment of ruby and sapphire. Gems
& Gemology 35: 90-92
Ertl A, Rossman GR, Hughes JM, Ma C,
Brandstätter F (2008) V3+ -bearing,
Mg-rich, strongly disordered olenite
from a graphite deposit near Amstall,
Lower Austria: A structural, chemical
and spectroscopic investigation. Neues
Jahrbuch für Mineralogie 184: 243-253
Fritsch E, Rondeau B (2009) Gemology:
The developing science of gems.
Elements 5: 147-152
E lements
TREATED NATURAL GEMS
Many of the tests to determine the geological or geographic
origin of a stone can also be used to find out if a stone has been
subjected to laboratory processes to change its color or other
properties. As an example, consider the corundum gems,
which are commonly heated to clarify and modify their color.
A recent development is the diffusion of beryllium, at the
level of 10 ppm or less, into the stones to change their color
to extents that range from subtle to dramatic. This treatment
was initially difficult to detect, but now a variety of analytical methods have been developed. Laser-induced breakdown spectroscopy (LIBS), LA–ICP–MS, and secondary ion
mass spectrometry (SIMS) now make it possible to detect
these low levels of beryllium in treated stones (Krzemnicki
et al. 2004; Abduriyim and Kitawaki 2006a, b).
CONCLUSIONS
The examples cited illustrate just a few of the methods, both
common and sophisticated, that are employed to determine
the origin of gem materials. In many cases, rigorous tests
prove to be too expensive compared to the value of the item
tested, or currently are too destructive for routine use. In
several instances, the geochemical reasons for some of the
observed differences are not fully understood. In other
cases, suitable tests are still lacking.
Giuliani G, France-Lanord C, Coget P,
Schwarz D, Cheilletz A, Branquet Y,
Giard D, Martin-Izard A, Alexandrov P,
Piat DH (1998) Oxygen isotope systematics
of emerald: relevance for its origin and
geological significance. Mineralium
Deposita 33: 513-519
Giuliani G, Chaussidon M, Schubnel H-J,
Piat DH, Rollion-Bard C, France-Lanord C,
Giard D, de Narvaez D, Rondeau B (2000)
Oxygen isotopes and emerald trade routes
since antiquity. Science 287: 631-633
Giuliani G, Fallick AE, Garnier V, FranceLanord C, Ohnenstetter D, Schwarz D
(2005) Oxygen isotope composition as
a tracer for the origins of rubies and
sapphires. Geology 33: 249-252
Guillong M, Günther D (2001) Quasi ‘nondestructive‘ laser ablation-inductively
coupled plasma-mass spectrometry
fingerprinting of sapphires. Spectrochimica
Acta B - Atomic Spectroscopy 56: 1219-1231
Hughes RW (1997) Ruby & Sapphire.
Chapter 12, World Sources. RWH
Publishing, Fallbrook, CA
Karampelas S, Fritsch E, Zorba T,
Paraskevopoulos KM, Sklavounos S (2005)
Distinguishing natural from synthetic
amethyst: the presence and shape of the
3595 cm-1 peak. Mineralogy and Petrology
85: 45-52
Krzemnicki MS (2007) “Paraiba”
tourmalines from Brazil and Africa.
Origin determination based on LA-ICP-MS
analysis of trace elements. SSEF Facette
14: 9. Available online at www.ssef.ch/
en/news/facette_pdf/Facette14_e.pdf
Krzemnicki MS, Hänni HA, Walters RA
(2004) A new method for detecting Be
diffusion–treated sapphires: Laser-induced
breakdown spectroscopy (LIBS). Gems
& Gemology 40: 314-322
Mattice G (1998) Demantoid From the Ural
Mountains of Russia. The Gem Spectrum.
http://palagems.com/gem_spectrum4.1.htm
Mittermayr F, Konzett J, Hauzenberger C,
Kaindl R, Schmiderer A (2008) Trace
element distribution, solid- and fluid
162
inclusions in untreated Mong Hsu
rubies. Geophysical Research Abstracts
10, EGU2008-A-10706, 2008 SRef-ID:
1607-7962/gra/EGU2008-A-10706
Muhlmeister S, Fritsch E, Shigley JE,
Devouard B, Laurs BM (1998) Separating
natural and synthetic rubies on the basis
of trace-element chemistry. Gems &
Gemology 34: 80-101
Peretti A (2008) New important gem
discovery in Tanzania: the Tanzanian
“Winza”-(Dodoma) rubies. Contributions
to Gemmology 7. www.gemresearch.ch/
news/Tanzania/Tanzania.htm
Peretti A, Schmetzer K, Bernhardt, H-J,
Mouawad F (1995) Rubies from Mong
Hsu. Gems & Gemology 31: 2-25
Rankin AH, Greenwood J, Hargreaves D
(2003) Chemical fingerprinting of some
East African gem rubies by Laser Ablation
ICP-MS. The Journal of Gemmology
28: 473-482
Rossman GR, Fritsch E, Shigley JE (1991)
Origin of color in cuprian elbaite from
São José de Batalha, Paraíba, Brazil.
American Mineralogist 76: 1479-1484
Schwarz D, Pardieu V, Saul JM, Schmetzer
K, Laurs BM, Giuliani G, Klemm L,
Malsy A-K, Erel E, Hauzenberger C,
Du Toit G, Fallick AE, Ohnenstetter D
(2008) Rubies and sapphires from
Winza, central Tanzania. Gems &
Gemology 44: 322-347
Yu KN, Tang SM, Tay TS (2000) PIXE
studies of emeralds. X-Ray Spectrometry
29: 267-278
Yui T-F, Zaw K, Limtrakun P (2003)
Oxygen isotope composition of the
Denchai sapphire, Thailand: a clue to
its enigmatic origin. Lithos 67: 153-161
Zwaan JC, Cheilletz A, Taylor BE (2004)
Tracing the emerald origin by oxygen
isotope data: the case of Sandawana,
Zimbabwe. Comptes Rendus Geoscience
336: 41-48
J une 2009
The Identification of Faceted
Gemstones: From the Naked
Eye to Laboratory Techniques
Bertrand Devouard1 and Franck Notari2
1811-5209/09/0005-0163$2.50 DOI: 10.2113/gselements.5.3.163
I
dentifying faceted gemstones involves practices that are closely related to
the classical determinative methods used by mineralogists. Measurements
of optical and physical properties, combined with acute observation using
various illumination techniques, are usually sufficient to determine the nature
of a gem. Determining the geographic origin of a gem or the enhancement
treatments it was subjected to, however, can require the expertise of an exper­
ienced gemologist and a combination of spectroscopic laboratory techniques.
advanced analytical methods, and
we illustrate these with specific
examples of problems encountered
in the characterization of gemstones.
SIMPLE TOOLS
FOR BASIC PROPERTIES
Optical Properties
Just as a mineralogist uses color,
relief, interference colors, and
conoscopic observation to identify
minerals in a rock thin section
examined under a polarizing microscope, the gemologist
observes the purity and color of a stone and estimates its
refractive index from its luster and the dispersion index
from the “fire” colors in light-colored stones.
Keywords : gems, gemology, optical properties, inclusions, spectroscopy
INTRODUCTION
Identifying a faceted gemstone first implies determining
the material of which it is made (the terminology used in
this article is illustrated in Figure 1). Then, the challenge
is to determine if the stone is natural or synthetic (Fritsch
and Rondeau 2009 this issue; Kane 2009 this issue) and,
most importantly, if the stone has undergone one or more
enhancement treatments. Gems are frequently subjected to
various treatments in order to improve their appearance
in terms of color and transparency, and hence increase their
commercial value (Nassau 1983). The gemologist may also
attempt to determine the geographic origin of the stone
(or, possibly, the method of synthesis) since the origin, when
it can be assessed, may influence the stone’s market value.
Mineralogists and petrologists routinely identify minerals
with a variety of simple or sophisticated methods. Gemologists
use similar techniques, but identifying gemstones differs
from identifying minerals in a rock for obvious reasons:
destructive methods and those that visibly alter the stone
are proscribed (hardness tests are typically not an option!).
Moreover, gems are sometimes set in jewelry and cannot be
unmounted, seriously limiting the scope of certain techniques.
Color is of course a most important property of gemstones.
Estimating and quantifying colors is a difficult task and
will not be discussed here (but see Hofer 1998). With a
handheld spectroscope, one can observe absorption or
emission bands in the visible spectrum, which can help
identification. Pleochroism of gemstones, when strong
enough, can be observed with the naked eye. It can also
be seen using a polarizing filter or, even better, a dichroscope, a small handheld optical instrument allowing a fine
comparison of pleochroic colors by juxtaposing the images
of the different rays (Fig. 2).
table
crown
Professional gemologists favor simple, quick, and inexpensive techniques, which are indeed sufficient in many cases
for species and variety identification. Think of identifying
hundreds of tiny stones in a pavé setting: efficiency is of
the essence. In some cases, however, observation and
simple techniques will fail to provide answers (e.g. the
detection of certain treatments and the stone’s geographical origin); then, laboratory methods are required. In the
present paper, we summarize the main methods of identification used in gemology, from the basic tools to so-called
girdle
pavilion
culet
Outline of a faceted gem (brilliant cut, side view) showing
the terms used in this paper. Faceting allows light entering the stone from above (e.g. path in red) to be refracted and reflected
so that rays are directed back to the observer, thus enhancing the
esthetics of the gem. Proportions and angles have to be adjusted to
the optical properties of the material. Computer simulations show
that not only refractive indices, but also more subtle phenomena
such as polarization on reflection, influence the visual aspect of a
faceted stone (Moses et al. 2004).
Figure 1
1 Laboratoire Magmas et Volcans (UMR 6524)
Université Blaise Pascal – CNRS, 5 rue Kessler
F-63000 Clermont-Ferrand, France
E-mail: [email protected]
2 GemTechLab Laboratory, 4 bis route des Jeunes
CH 1227 Acacias, Geneva, Switzerland
E-mail: [email protected]
E lements , V ol . 5,
pp.
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163
J une 2009
The refractive index is a key property for identifying a
gemstone. It can be efficiently measured to the second
decimal place with a refractometer, a simple instrument
exploiting total reflection of light on a facet (usually the
table) of a cut gemstone. Skilled gemologists can also determine whether the stone is anisotropic, measure the two
indices (birefringence) in the section corresponding to the
facet (and repeat the measurement for various orientations,
if the stone is large enough), and even determine the
uniaxial or biaxial character and the optical sign.
Another easy way to estimate the birefringence of a
gemstone is with a magnifying loupe or a binocular microscope. The gemologist looks through the stone’s table to
observe if the edges of the pavilion facets appear to be
doubled (Fig. 3). As with a calcite rhomb, anisotropic materials will show doubling, the effect being more or less
pronounced depending on the value of the birefringence,
the direction of observation, and the length of the optical
path inside the gem.
A
The polariscope is another simple tool, which makes use
of crossed polarizing filters and a source of light. This
instrument separates optically isotropic from anisotropic
gemstones. With a glass bead stuck on a small handle
(conoscope), it allows conoscopic measurements as with a
polarizing microscope. In addition to measuring optical
properties (e.g. 2V angles) and detecting anomalous double
refringence (strain), the polariscope and conoscope also serve
to orient gemstones prior to spectroscopic measurements.
These simple tools, combined with careful observation, are
often sufficient to unambiguously identify the mineral
species of a gemstone. For instance, a dichroscope and a
handheld spectroscope would reveal whether the “Black
Prince’s ruby” (a 170 carat red stone set in the front of the
imperial state crown of the United Kingdom) is a ruby or
a red spinel (it actually is a spinel). For a more detailed
description of the basic tools of gemology, refer to Webster
and Read (1994).
Other Physical Properties
Other basic properties are useful for identifying gemstones.
The measurement of specific gravity using heavy liquids
or a hydrostatic scale gives very precise results on inclusionfree gemstones. As an example, it has been shown that
emeralds synthesized using flux methods can be distinguished from natural or hydrothermally synthesized emeralds by their specific gravity (S.G.), because the channels
in the structure of the flux-grown crystals are empty
(giving S.G. = 2.65–2.66), whereas they contain water and
alkali ions in natural or hydrothermally synthesized stones
(S.G. > 2.68).
B
Tanzanite, a variety of zoisite, is an attractive gem with
spectacular pleochroism. (A) Pleochroism in an unheated
tanzanite, observed in immersion with one polarizing filter set under
the specimen. In such conditions one can observe three colors: purple,
blue, and yellow, corresponding to α, β, and γ rays, respectively. The
stone pictured weighs 0.45 carat. (B) The three rays, polarized at
right angles, can be observed in pairs with a dichroscope, depending
on the observation direction. Heat treatment of tanzanite changes
the color of the γ ray from yellow to blue, resulting in stones with an
intense blue color when the table of the stone is cut parallel to the
(100) face of the rough crystal, or a purplish blue color if the table is
cut perpendicular to (001). Picture F. Notari
Figure 2
A
Magnetism is another physical property that can be evaluated with simple testing, for example, by floating a stone
on a small piece of polystyrene foam placed on water and
submitting it to the magnetic field of a strong magnet.
Paramagnetic (iron-containing) minerals can be detected
this way. The method can also be applied to identify
synthetic diamonds grown in metal flux. These diamonds
are often weakly magnetic because they contain impurities
from the flux.
Estimating thermal conductivity can also aid in gem identification. Stories are told of gemologists able to recognize
glass from quartz or brown topaz from low-priced citrine
with their eyes closed, just by estimating the thermal
conductivity from the sensation of cold (for quartz) when
holding the stones against their lips. Thermal conductivity
is the property used in “diamond tester” instruments
intended to distinguish diamonds from their simulants.
Although popular, diamond testers are not foolproof. The
B
Birefringence can be estimated by observing the doubling
of edges between facets in the pavilion and culet while
looking through the table or through the crown of a faceted gem.
(A) Diamond, isotropic, shows no doubling. Width of field ca. 1.6 mm.
(B) Moissanite (SiC, 6H polytype), a convincing simulant of diamond
with a birefringence of 0.036, shows a typical fuzzy aspect due to
Figure 3
E lements
C
moderate doubling of edges, and it can be distinguished from diamond
in this way. Field of view ca. 1.6 mm. (C) Zircon, with a high birefringence (0.055, when not metamict), exhibits strong doubling. Field of
view ca. 5 mm. Estimating the birefringence with this method implies
taking into account the thickness and crystallographic orientation of
the stone. Photos F. Notari
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J une 2009
older instruments cannot make the distinction between
diamond and synthetic moissanite, a convincing simulant
that appeared on the market in the late 1990s (Nassau
2000) and that has a high thermal conductivity, close to
that of diamond. Synthetic moissanite, however, can be
recognized using other simple techniques, such as observing
its birefringence with a loupe (Fig. 3b).
A
OBSERVATION IS KEY
If the measurement of physical properties with simple tools
allows one to determine the mineral species, it usually does
not reveal if the stone is natural or synthetic, if it has been
treated, or its geographic origin. In most cases, however,
these questions can be addressed by careful observation
using a variety of illumination techniques at various wavelengths. The naked eye or a loupe might be sufficient for
an experienced gemologist, but more reliable observations
are made with a binocular microscope (Fig. 4). In some cases
it might be necessary to observe a stone in an immersion
cell containing a liquid with a matching index of refraction, in order to reduce the disturbing refraction effects
on the various facets of the stone. As observation is a very
simple technique, it is sometimes felt that it is not great
science. Even if not very sophisticated, observation is as valid,
robust, and efficient a scientific method as any other.
Illumination and Luminescence Techniques
When observing gemstones under the binocular microscope, illumination is critical. Transmitted light; apical,
oblique, or lateral illumination with concentrated or
diffused light; and dark-field imaging can reveal different
features. For example, natural and synthetic amethysts can
be distinguished by the presence or absence of twinning,
as well as its nature, when observed with transmitted light
in immersion liquid with the use of crossed polarizing
filters. (Fig. 5) (Crowningshield et al. 1986; Notari et al. 2001).
B
In modern gemology laboratories, visual observation is
important. At GemTechLab (Geneva), roughly one-half
of the room is occupied by binocular microscopes (A), while the other
half (B) contains analytical instruments such as ED-XRF, FT-Raman,
FTIR, and UV-NIR spectrometers.
Figure 4
Some gemstones display different colors depending upon
the color temperature of the light source (Liu et al. 1994).
Such “color-change” gems, of which alexandrite is the
archetype (reddish under incandescent light and greenish
under natural light), are eagerly sought by gem collectors.
As an alternative to polychromatic visible light, an ultraviolet (UV) or a monochromatic source of light can be used
to observe luminescence colors and heterogeneity in a
stone. Although luminescence (i.e. fluorescence, phosphorescence, or both) can sometimes be observed with a simple
UV lamp (Robbins 1994), special instruments have been
devised for the observation of luminescence in gems under
the binocular microscope. Diamond View (TM), developed
by De Beers’ Diamond Trading Co., is equipped with a UV
source at about 220 nm, whereas the U-Visio ©, developed
at GemTechLab, uses various intense wavelengths for excitation from 365 to 500 nm (mainly 430–450 nm). This
allows observation in specific regions of the spectrum, after
filtering out the excitation wavelengths and undesirable
emissions, e.g. the Cr3+ red fluorescence in rubies.
As an example, a variety of luminescence colors can be
exhibited by diamonds. They are induced by impurities
and defects. About a third of all gem diamonds luminesce.
Most commonly, they display a blue luminescence under
long-wave UV light caused by N3 centers (clusters of three
atoms of nitrogen replacing three carbon atoms around a
vacancy; Woods 1984). Other types of defects in diamond
can, however, induce luminescence in other colors, such
as the spectacular “chartreuse” (yellowish green) luminescence induced by H3 centers (the association of a pair of
nitrogen atoms—an A aggregate—with a vacancy), which
can usually be observed under intense white-light excitaE lements
Growth features can assist in distinguishing natural from
synthetic gems. The interference fringes (Brewster fringes)
observable in this 5.60-carat amethyst lie in the major rhombohedron
(r) planes and are caused by polysynthetic twinning (Brazil twin law).
These fringes, visible when observing the stone parallel to the optic
c-axis between crossed polarizing filters, are robust evidence for the
natural origin of amethyst. Courtesy Thomas Hainschwang, Gemlab
laboratory, L ichtenstein
Figure 5
tion. Luminescence in diamond is a powerful method for
distinguishing natural from synthetic diamonds and for
identifying certain treatments (see Fig. 6). In several cases,
orangey fluorescence can indicate Be-diffusion treatment
in corundum. For detailed investigations, the visual observation of luminescence has to be replaced by spectroscopic
analysis of the emitted light (Shigley et al. 1993; EatonMagaña et al. 2007).
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J une 2009
A
B
C
Growth patterns, revealed by luminescence, can help to
distinguish natural and irradiated diamonds from synthetic
stones. (A) The irregular zoning of this apparently black diamond
of 1.27 carats is typical of a natural stone. In addition, the sharp
luminescence concentrated at the edges of the faceted stone is evidence
for treatment by neutron irradiation. (B) Irregular luminescence
patterns are spectacular in this complex 0.20-carat natural brown
diamond from Argyle (Australia), which displays a central zone (also
refracted by the crown facets) with green luminescence, typical of
so-called “CO2-rich” diamonds, surrounded by an overgrowth of type
Ia diamond with typical blue luminescence. (C) By contrast, this
0.22-carat synthetic yellow diamond shows green luminescence
typical of diamonds grown at HP–HT in a metal flux: straight patterns,
with sector zoning marked by the traces of {111} faces and weak
oscillatory zoning along {100} faces. Such yellowish green luminescence,
linked to Ni–N defects, is never observed with such a distribution in
natural colorless or yellow diamonds.
Figure 6
The Internal World of Gemstones
Most gemstones, even those of high clarity, contain inclusions. These inclusions, solid (minerals or melts) or fluid,
tell the story of the stone’s genesis and can be indicative
of a geological context (Groat and Laurs 2009 this issue)
or even a specific deposit. For synthetic stones, inclusions
of flux, platelets, or bubbles in flame-fusion (Verneuil
method) corundum or spinel (the latter often displaying
typical “spindle-shape” bubbles) are telltale signs of their
method of synthesis. The variety of inclusions in gemstones
and their use in identification are described in numerous
articles and books, including the reference works by
Gübelin and Koivula (1986, 2005, 2008), which contain
thousands of photographs. The inclusions of U-rich thorianite in Figure 7a are known in corundum from mainly
three deposits (Mogok in Myanmar, Kashmir, and
Andranondambo in Madagascar). They are readily identified under U-Visio observation by the fluorescent halo
surrounding each of them (Fig. 7b). Combined with other
evidence (such as other mineral inclusions, trace element
chemistry, and UV–visible spectroscopy), such inclusions
can help to determine the geographic origin of the stone.
The detection of heat treatment in corundum is currently
a major issue in the gem trade (Themelis 1992; Emmett
1999). Low-quality metamorphic corundum crystals are
routinely treated at high temperature (HT) in order to
improve their clarity and/or color (see Fig. 6 in Fritsch and
Rondeau 2009 this issue). If the heat treatment is carried
out in a reducing atmosphere, the treated crystals can
incorporate Ti from rutile (TiO2 ) inclusions into the
corundum structure (the color of blue sapphires is in part
due to Fe2+ –Ti4+ charge transfer). It is possible to obtain
the inverse effect (lightening a blue color that is too dark)
by heating in an oxidizing atmosphere. Figure 7c shows
inclusions in an untreated blue sapphire, as indicated by
the presence of fine rutile needles (called “silks”) and
böhmite. For comparison, Figure 7d shows an uneven distribution of color in a heat-treated sapphire, clearly revealing
“ghosts” of former rutile needles. However, the interpretation of rutile morphologies by microscopic observation
E lements
requires careful examination and some knowledge of
crystal morphology and orientation. Dotted alignments of
inclusions in sapphire might represent partially dissolved
rutile needles after heat treatment at high T (>1600°C), but
they can also be alignments of polycrystalline böhmite,
which are not indicative of HT treatment. Unambiguously
identifying these two kinds of inclusions in corundum
requires determining their orientation relative to the c-axis
(optic axis) of the host: rutile inclusions are always distributed in the (0001) plane and cross each other at an angle
of 60°, whereas böhmite inclusions align parallel to the
<1̄2̄31> directions (junctions of the rhombohedron faces).
A second type of HT treatment in corundum incorporates
the coloring elements by diffusion from the outside (see
Shigley and McClure 2009 this issue). Recently, a new type
of diffusion-treated sapphire appeared on the market, characterized by very attractive pinkish orange (“padparadscha” variety) to deep orange colors. This treatment was
identified as diffusion of Be2+ (Emmett et al. 2003). Figure 7e
shows the original reddish color of the stone, the yelloworange zones due to Be diffusion, and blue Ti-diffusion
halos around prismatic rutile inclusions. In addition to the
evidence for HT treatment and beryllium diffusion, the
stubby rutile inclusions are characteristic of the Songea
(Tanzania) deposit.
Crystal Growth as Revealed by
Color and Luminescence
As crystals grow, variations in their environment can be
recorded by the heterogeneous distribution of trace
elements or defects. Oscillatory or sector zoning are often
observed in colored gemstones. Natural stones display very
different zoning from synthetic crystals grown in a dissimilar, better-controlled environment. As a result, zoning
patterns can often be used to distinguish natural from
synthetic stones. When heterogeneities of color are not
observed, growth patterns can sometimes be revealed by
luminescence (Fig. 6 and Fig. 7b).
Figure 6 shows typical growth patterns displayed by natural
and synthetic diamonds. While natural stones often show
complex zoning (Fig. 6a, 6b), flux-grown synthetic diamonds
display very regular sector zoning, very little oscillatory
zoning, and a green fluorescence caused by Ni impurities
coming from the metal flux (Fig. 6 c). In addition, strong
luminescence of the edges between facets (Fig. 6a) is proof
of treatment by irradiation (Boillat et al. 2001).
EXTENDING THE EYE WITH SPECTROSCOPY
When simple procedures fail to provide an unambiguous
diagnosis, gemology laboratories resort to spectroscopic
methods. Examples of situations requiring spectroscopy
are the identification of HT treatment subsequent to irradiation in yellow diamonds and the identification of
synthetic or heat-treated, natural, inclusion-free, colored
166
J une 2009
A
stones. Large colored stones without any
inclusions or heterogeneity of color are
always suspicious since they are likely to
be synthetic, but on the other hand they
command high value if they are natural.
B
C
D
E
From Ultraviolet to Infrared
Visible light optical spectroscopy quantifies
what the eye sees as color and, in favorable
cases, assists in identifying the origin of
color (Fritsch and Rossman 1987, 1988;
Rossman et al. 1991). UV–visible spectrometers or Raman spectrometers can also be
used for photoluminescence spectroscopy
(Chalain et al. 1999). In red spinel, for example, the Cr3+
emission bands do not exhibit the same pattern in natural
as compared to synthetic samples (Notari and Grobon 2003).
Spectroscopy is most interesting to investigate domains of
the electromagnetic spectrum that are not detected by the
human eye, such as UV and IR. Vibrational spectroscopies
can be used as “fingerprint methods” for nondestructive
identification of species or varieties (e.g. opal-A from opalCT), particularly when other gemological properties are
very similar. Raman spectroscopy and IR specular reflectance in the 400–1400 cm-1 range (Hainschwang and
Notari 2008) are particularly helpful for identifying
unusual gems. For instance, these methods can distinguish
between the rare gems “musgravite” (magnesiotaaffeite6N’3S) and “taaffeite” (magnesiotaaffeite-2N’2S), which
are otherwise nearly indistinguishable except using X-ray
diffraction. Micro-Raman spectroscopy is another common
method for determining the nature of inclusions deep
inside gemstones.
IR spectroscopy is routinely applied to detect trace amounts
of water and the presence of organic compounds, and to
characterize diamond. For diamond, this technique
provides the type and speciation of impurities (N, H, B)
and reveals many small, sharp, absorption features related
to the treated or synthetic nature of the gem (Zaitsev 2001).
As most gems are inorganic, the presence of organic molecules can be proof of impregnation with a resin, oil, or
polymer. Trace amounts of water absorb IR differently in
some natural gems compared with corresponding hydrothermal synthetics, and this feature can reveal the presence
or absence of heat treatment in inclusion-free corundum.
In corundum, the absorption band at 3309 cm-1, accompanied by four satellite bands (at 3376, 3295, 3232, and
3187 cm-1), is due to OH dipoles linked to Ti or Fe–Ti pairs.
These features are observed in gems that have undergone
an HT event. The observation of these OH bands is thus
robust evidence of heat treatment in natural corundum of
metamorphic origin but has to be considered with other data
(such as trace element content or visible spectroscopy) that
can provide relevant information on the geological context.
E lements
Inclusions in gemstones are often typical of mineral
species, geological setting, method of synthesis, or
treatment. (A, B) Micrographs of a yellow, unheated sapphire from
Mogok, Myanmar, showing fluid, calcite, and U-rich thorianite
[(Th,U)O2] inclusions. Field of view ca. 1.8 mm. Transmitted light (A)
and corresponding image under U-Visio luminescence (B), showing a
reddish luminescent background due to traces of Cr3+, a yellow
luminescent zoning due to color centers associated with traces of
Mg2+ (invisible in transmitted light), and bright yellowish green
luminescent halos around the U-rich thorianite crystals. (C) Rutile
needles (“silks,” on the left) and polycrystalline böhmite (on the
right). The aspect of these inclusions in this 12.69-carat blue sapphire
from Myanmar proves that the stone has not been subjected to HT
treatment. (D) Heat treatment in sapphire causes the diffusion of Ti
from rutile inclusions into the corundum, enhancing its blue color
and leaving in some cases “ghosts” of rutile silks, as in this treated
6.46-carat sapphire. (E) This image is typical of Be-diffusion
treatment applied to a sapphire from Songea (Tanzania); yellowish
and orangey zones of color were induced by the treatment. The
observation of blue diffusion halos (“frog eggs”) around the stubby
rutile inclusions typical of Songea is indicative of both heat treatment
and the geographic origin. This exemplifies how, in some cases,
classical gemology can detect Be-diffusion treatment, which
otherwise requires microdestructive LA–ICP–MS or LIBS analysis of Be
when it leaves no typical traces. Field of view ca. 2 mm. Micrographs
A,B,C,D: F. Notari; E: E. Fritsch
Figure 7
Using X-rays for Chemical Analysis
Major and trace elements in gemstones can be analyzed
by secondary X-ray emission spectroscopy (see Rossman
2009 this issue). Energy dispersive X-ray fluorescence
(ED-XRF) is the most common technique, as it requires no
sample preparation. Analytical scanning electron microscopy is also commonly employed, especially the more
recent “variable pressure” instruments that allow observations and qualitative analyses without the need to coat the
samples with a conductive layer.
The trace element content of gemstones can be used to
discriminate natural from synthetic stones, different
origins of natural stones, or the method of synthesis. This
is especially useful for rubies with no visible inclusions or
color heterogeneities (Muhlmeister et al. 1998). Similarly
to spectroscopic methods, comparison of trace element
compositions must be done cautiously; to be meaningful,
the technique should be applied only to stones with similar
color and the analyses should be performed away from
microscopic inclusions.
167
J une 2009
Microdestructive Techniques
Even if the rule is that gem analyses must be nondestructive,
it might be necessary in some cases to resort to micro­
destructive techniques, some of which are becoming
increasingly popular in gemology laboratories. In these
techniques, a tiny quantity (typically 10 to 50 microns in
diameter) of the gemstone is sampled, which is invisible
to the naked eye. The method is therefore considered to
be acceptable, especially if the analysis is made on the
girdle of the stone.
The main microdestructive techniques in gemology are
laser-induced plasma (or breakdown) spectroscopy (LIPS
or LIBS) and laser ablation–inductively coupled plasma–
mass spectrometry (LA–ICP–MS). Both techniques allow
the analysis of trace elements with detection limits down
to the ppm level (or lower) and require no preparation of
the samples. Moreover, both techniques allow the detection
of light elements, for example, Be in Be-diffused sapphires,
which is currently impossible with other available techniques. Secondary ion mass spectrometry (SIMS, commonly
referred to as “ion probe”) also offers unique possibilities
for the analysis of trace elements and isotopic compositions
and is even less destructive than laser-based techniques.
Giuliani and coworkers have traced the origin of emeralds
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Luminescence sous excitation visible des
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Chalain J-P, Fritsch E, Hänni HA (1999)
Detection of GEPOL diamonds, a first
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Crowningshield R, Fryer CW, Hurlbut C
(1986) A simple procedure to separate
natural from synthetic amethyst on the
basis of twinning. Gems & Gemology
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Eaton-Magaña S, Post JE, Heaney PJ, Walters
RA, Breeding CM, Butler JE (2007)
Fluorescence spectra of colored diamonds
using a rapid, mobile spectrometer.
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Emmett JL (1999) Fluxes and the heat
treatment of ruby and sapphire. Gems
& Gemology 35: 90-92
Emmett JL, Scarratt K, McClure SF, Moses T,
Douthit TR, Hughes R, Novak S, Shigley
JE, Wang W, Bordelon O, Kane RE (2003)
Beryllium diffusion of ruby and sapphire.
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Fritsch E, Rondeau B (2009) Gemology:
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Elements 5: 147-152
Fritsch E, Rossman GR (1987, 1988) An
update on color in gems, Parts 1-2-3.
Gems & Gemology 23: 126-139; 24: 3-15;
24: 81-102
Giuliani G, Chaussidon M, Schubnel H-J,
Piat DH, Rollion-Bard C, France-Lanord
C, Giard D, de Narvaez D, Rondeau B
(2000) Oxygen isotopes and emerald
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as determined with SIMS (e.g. Giuliani et al. 2000). SIMS,
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AND THE GAME GOES ON
With the discovery of new gem deposits, such as the
recently discovered Winza ruby deposit in Tanzania, previously unknown inclusion parageneses come to light, as
well as new trace element compositions and spectral
features. As new methods of synthesis and treatment are
devised, gemology has to adapt by developing new methods
of identification and by using new instruments. At the
moment, major laboratories are refining techniques to identify gem-quality synthetic diamonds grown by the chemical vapor deposition (CVD) technique (Hemley et al.
2005). Hexagonal moissanite (SiC) can be easily distinguished from diamond on the basis of its birefringence
(Fig. 3), but silicon carbide is a polytypic structure, and
although manufacturers have failed so far to master the
synthesis of gem-quality SiC with polytypes different from
the usual 6H one, it is to be expected that cubic (polytype
3C) moissanite will eventually appear on the market,
depriving gemologists of a simple identification criterion.
Gübelin EJ, Koivula JI (1986, 2005, 2008)
Photoatlas of Inclusions in Gemstones.
Volume 1, 2, and 3. Opinio Verlag, Basel
Hainschwang T, Notari F (2008) Specular
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Nassau, K (2000) Synthetic moissanite:
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Notari F, Boillat PY, Grobon C (2001)
Quartz α-SiO2 : Discrimination des
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NV, Malinovsky IY, Pal’yanov YN (1993)
The gemological properties of Russian
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Seeking Low-Cost Perfection:
Synthetic Gems
Robert E. Kane*
1811-5209/09/0005-0169$2.50 DOI: 10.2113/gselements.5.3.169
S
ynthetic gems are superlative examples of crystal growth. Today,
industrial and scientific crystal growth is a highly sophisticated endeavor
employing a wide range of methods. Many of these have been adapted
to grow gems for jewelry use. Most major gemstones have been synthesized,
and these products are commercially available around the world, often at a
fraction of the cost of a natural gem of comparable size and quality. Distinguishing
them from their natural equivalents involves a number of interesting challenges.
Inclusions (internal features) observed by microscopy often provide conclusive
proof of synthetic origin. When routine testing procedures (refractive index,
specific gravity, fluorescence, and internal inclusions) do not provide sufficient
evidence, laboratories must employ more advanced analytical instrumentation.
Keywords : gemstone, synthetic gem, man-made gem, laboratory-grown gem,
gem testing, gemology
Why Synthetic Gemstones?
Synthetic gemstones are produced in a laboratory—they
are gems made by man (Fig. 1). They have essentially the
same chemical composition and crystal structure as their
natural counterparts. Thus synthetic gems closely duplicate
the physical and optical properties of natural stones. Gemological
guidelines dictate that the name of a man-made gem be
preceded by the word synthetic (e.g. synthetic ruby), though
many manufacturers use the terms created or cultured (e.g.
created emerald).
Scientists often ask why synthetic gems are considered in
such a different light from natural gems, since they are chemically and crystallographically analogous to the natural gems.
In fact, the physical and optical properties of synthetics
are often “better” than those of natural gems: larger dimensions,
better and more homogeneous color, and fewer inclusions.
But since the creation of the first modern synthetic gem
circa 1885, the “Geneva ruby” (see Fritsch and Rondeau 2009
this issue), manufactured gems have always sold at significantly lower prices than natural gems of equal size and
quality. A rather dramatic example was provided in 2006
by an 8.62-carat untreated Burmese ruby that sold at Christie’s
for a world-record price of $3.6 million, a staggering
$420,000 per carat. A comparable Verneuil (see Table 1) synthetic
ruby retails for around $6 per carat, and a similar flux-grown
synthetic ruby commands approximately $650 per carat.
The vast majority of buyers value the authenticity of a
natural gem over the “perfection” of its synthetic counterpart. It is often a question of affordability—when given
the choice, most of us would choose a natural product,
* Fine Gems International
P.O. Box 1710, Helena, Montana 59624, USA
E-mail: [email protected]
E lements , V ol . 5,
pp.
169–174
whether it is a natural granite
countertop over a man-made
Formica one, or a natural emerald
over a synthetic one. Rarity is also a
factor—fine-quality natural gem­­
stones are rare, whereas their
­man-made analogues can be massproduced.
Hundreds of minerals have been
synthesized for experimental and
industrial applications—often as
crystals too small to be faceted or
not of gem quality, or as species
not typically used as gemstones.
Table 2 lists the major gem materials and when they were first
synthesized.
Historically, many of the breakthroughs in gem synthesis have been a direct result of the
synthetic-gemstone manufacturer’s own investigations and
pioneering research. For example, Carroll Chatham,
founder of Chatham Created Gems, brought to market the
first commercially available, faceted, flux-grown, synthetic
emeralds in the 1940s. However, many synthetic minerals
were originally developed through experimental petrology;
for example, tourmaline was synthesized to study the
origin of color in tourmaline (Barnes 1950; Taran et al.
1990, 1993, 1996). These man-made tourmalines were overgrowths on the order of 1 mm or less in thickness, and
thus synthetic tourmaline has not yet reached the size and
quality required for the gem market. Also, the initial
synthesis of opal helped in the in-depth understanding of
the unique structure of natural opal (Jones et al. 1964) and
led to further development of photonic crystals, which
currently have widespread technological applications.
Interestingly, although patents for a technique to grow opal
were filed by the Australian organization CSIRO in 1964,
it was not until 10 years later that the French synthetic
emerald maker Pierre Gilson finally learned how to produce
man-made opals that were stable, beautiful, and large
enough for use in jewelry. In contrast, synthetic sodalite
was grown hydrothermally by the Chinese for gemological
applications (which apparently never came to be), but may
ultimately be of interest to materials scientists (see, for
example, Trill et al. 1999).
For the past several decades, many of the advances in gem
synthesis have been by-products of technological research,
particularly in the field of lasers. Indeed, ruby and emerald
make excellent solid-state lasers when the crystals are large
and homogeneous. Contributions also came from the semiconductor industry (most recently with moissanite, SiC),
and work on integrated circuits, microelectronics, computer
memory devices, and the like. In many instances, these
169
J une 2009
16
17
1
13
2
3
18
15
21
14
6
19
7
5
22
20
4
10
23
9
8
11
12
25
Primary Methods of Gem
Crystal Growth
Different laboratory gem-manufacturing techniques
often employ specific growth methods, which produce
synthetic gems with predictable features: characteristic crystal habits
and most notably typical inclusions. Understanding these often enables
the gemologist to identify the growth method and the specific manufacturer. Shown here are synthetic flux-grown emeralds produced by
Gilson (3, 6, 7), Seiko (5), Lennix (8), Inamori (9), and Chatham (10,
11, 12), as well as Russian hydrothermal (1, 2) and Russian flux (4)
synthetic emeralds. The blue synthetic sapphire crystals (13, 15) were
grown by Chatham in a flux environment, and the faceted blue sapphire (14) by a melt method. The synthetic rubies were made by several
methods: Russian hydrothermal (16, 17), Chatham flux (19, 22),
Douros flux (18, 21), Ramaura flux (20, 23), and Kashan flux (24, 25).
The faceted synthetic stones range in weight from 1.21 to 6.57 cts, and
the synthetic crystals range from 10.21 to 482.51 cts. Synthetics
courtesy of Thomas Chatham ; photo © Tino H ammid and Robert E. K ane
Figure 1
Today, industrial and scientific crystal growth around the
world is a highly sophisticated endeavor employing many
different methods. Many of these have been adapted to grow
gems. The groupings in Table 1 (adapted from Nassau 1980)
illustrate some of the major techniques utilized by professional crystal growers.
developments originated from billion-dollar corporations
investing hundreds of millions of dollars in crystal-growth
research. In contrast to the very small number of jewelryquality synthetic gem manufacturers, many thousands of
researchers worldwide are involved in industrial crystal growth.
The general public is unaware that man-made crystals influence virtually every aspect of modern living, either directly
or indirectly. More than 400 tons of synthetic diamonds
are produced each year for industrial use, such as in machining
and cutting tools. Man-made crystals help to regulate our
cities’ power supplies. They play an integral part in the systems
used to manage our financial centers and credit card
purchases; enable operation of our cell phones, digital
cameras, televisions, and (synthetic) quartz watches; supervise communications; direct airline traffic; and help diagnose and cure diseases. As some of these synthesis technologies
make their way into gem and jewelry applications, the
gemologist is faced with increasingly difficult challenges
when it comes to differentiating between synthetic and
natural gems. In gem synthesis, there have been more
developments in the last two decades than in the previous
50 years.
E lements
24
Melt techniques are among the oldest and simplest—they
require that the gem species melts congruently. Melt techniques are commonly employed to grow ruby, sapphire,
chrysoberyl (alexandrite), and many crystals with a garnet
structure (e.g. yttrium aluminum garnet, YAG). For those
gems that melt incongruently—for example beryl—solution growth (in particular, under hydrothermal conditions)
comes close to their natural conditions of formation. Some
gem materials can be synthesized only by a single method;
synthetic moissanite, for example, requires sublimation
(Table 1), and cubic zirconia requires skull melting (Table
1; Fig. 2). Others, in particular synthetic ruby, are grown
by a variety of methods—for example, melt crystallization
(flame fusion or Verneuil), hydrothermal solution, and flux
growth (Fig. 3). In general, melt-crystallization techniques
are low-cost and high-volume, yielding very inexpensive
synthetic rubies and sapphires. Synthetic rubies and
sapphires grown by hydrothermal solution or flux solution,
on the other hand, are high-cost and low-volume. The synthetic
stones produced by these methods can cost as much as a
hundred times more than a melt-grown ruby or sapphire.
Also, the synthesis of diamond by high-pressure and hightemperature solution growth (Fig. 4) requires very expensive equipment.
170
J une 2009
Table 1
General Categories of Gem and Mineral
Crystal-Growth Techniques
A
Melt growth
Solidification in a container
Czochralski growth (pulling from a seed in contact
with the corresponding melt)
Verneuil or flame-fusion growth
(projecting molten oxides from a flame on a seed)
Zone growth (crystallizing from a seed in a corresponding
powder, locally molten)
Skull melting (mass crystallization from a molten volume
using the same unmelted powder as the crucible)
Solution growth
Growth from water or other solvents
Gel reaction growth
Hydrothermal growth (growth in a fluid under
an appropriate pressure and temperature)
Flux and flux zone growth (growth in an anhydrous molten salt)
Growth by electrolysis
High-pressure flux growth
Vapor phase growth
Sublimation growth
Growth by reaction in a vapor phase
Chemical vapor phase transport growth
A dapted from Nassau (1980)
Variations Unique to Gem Synthesis
Reagent-grade chemicals and controlled conditions enable
the gem crystal growers not only to perfect a natural process,
but in some cases “improve” upon it by creating unique
gems. Exceptionally bright, vivid colors not found in nature
can be created in synthetic gems. For example, Co2+ in
sufficient quantity can produce an unnaturally bright blue
color in hydrothermally grown synthetic quartz. In the
hydrothermal beryl crystals grown in Russia, a rich “turquoise”
blue has been achieved by adding copper.
B
While naturally yellow sapphires can be colored by Fe3+,
heated dark yellow sapphires owe their color to the O - ion
that accompanies Mg2+ in a charge-compensation mechanism
(Emmett et al. 2003). The O- ion is also referred to as a trapped
hole center. Ni is responsible for the bright lemon yellow
of Verneuil-grown (or flame-fusion) synthetic sapphires.
The use of alternative color-causing elements might lead a
purist to wonder if these are imitations rather than true synthetics,
since there are no naturally occurring equivalents.
Identification of Synthetic Gemstones
Identification of gems is one of the core activities of gemologists (Fritsch and Rondeau 2009 this issue). For much of
the twentieth century, the modestly equipped expert
gemologist could successfully identify most synthetic gem
materials. As the technological sophistication of gem
synthesis has increased—exponentially in the case of
diamonds—the challenge facing the jeweler-gemologist has
also increased.
Colorless synthetic cubic zirconia (CZ) is produced annually
by the ton for use as a faceted imitation of diamond (A).
Numerous colors can be produced to imitate other gem species and
varieties. For example, the addition of cobalt produces purple cubic
zirconia, and the color becomes a deep blue with increased stabilizer
concentration. (B) The irregular shape of the rough CZ crystals is
typical of the skull melting method used to grow them. Photo A by
Shane F. McClure, courtesy of GIA, and photo B by Tino Hammid
Most physical and optical properties of synthetic gems
overlap with those of their natural counterparts (with the
exception of the presence and nature of internal inclusions). However, a few other differences in properties
between natural and synthetic gems also exist. Some
hydrothermal synthetic emeralds, such as those made by
the Biron Corporation, possess lower refractive indices and
birefringence than typical natural emeralds (Kane and
Liddicoat 1985). This is also the case with flux-grown
synthetic emeralds. These differences in properties can be
explained in part by the lesser number of molecules or ions
occupying channel positions.
E lements
Figure 2
Inclusions can often provide conclusive proof of synthetic
origin. The first “Geneva rubies” caused panic in the mid1880s among European jewelry dealers because they were
initially sold as genuine natural gems. Since then, detailed
observation under the microscope and the interpretation
of internal features have continued to provide conclusive
171
J une 2009
After decades of anticipation, synthetic diamonds
grown under high pressure and high temperature
(HP–HT) conditions are now a commercial reality in the international
market, both as loose stones and set in jewelry. Shown here are
examples of 1.00–1.25 carat synthetic yellow diamond jewelry
produced by Gemesis Corp (the colorless diamonds are natural). The
unset synthetic diamonds (weighing less than 1.00 carat each) are
from Chatham Created Gems and Lucent Diamonds. Composite photo
jewelry images courtesy of G emesis Corp. Loose diamond photos by H arold
and Erica Van Pelt; courtesy of GIA
Figure 4
Hand-painted illustration from Edmond Frémy’s 1891
book on the synthesis of ruby. In 1887, Frémy and Feil
were the first to synthesize ruby by the flux method. This rare plate
shows tiny flux-grown synthetic rubies filling a crucible, as well as
beautiful examples of 19th century French-made jewelry set with
Frémy’s faceted flux-grown synthetic rubies. Courtesy of GIA
Figure 3
proof of synthesis in many types of man-made gems (Fig. 5).
The appearance and nature of healed fractures, as well as
the presence of minute amounts of flux or crucible material,
are particularly helpful in the identification of synthetic gems.
The inclusions present in a synthetic gemstone are often
characteristic of a particular laboratory growth method
(see, for example, Sunagawa 2005). Rubies and blue
sapphires grown by the flame-fusion melt method often
show curved growth layers and spherical, elongated, or
distorted gas bubbles. Those produced by flux melt techniques frequently reveal residual unmelted flux, or inclusions of flux with a retraction bubble (due to volume loss
during cooling to room temperature). Hydrothermally
grown crystals often display “chevron-like,” “mosaic,” or
“zigzag” growth structures. These are phantom features of
fast-growing faces that are not smooth but covered by
growth hillocks centered on spiral dislocations.
When routine, standard testing procedures—refractive
index, specific gravity, fluorescence, internal inclusions
observed by microscopy—do not provide sufficient evidence
to determine the synthetic or natural origin of a gemstone,
E lements
laboratories must employ more advanced analytical instrumentation. For example, separating natural and synthetic
rubies on the basis of trace element chemical composition,
as determined by energy-dispersive X-ray fluorescence
(ED-XRF) spectrometry (Muhlmeister et al. 1998; Devouard
and Notari 2009 this issue; Rossman 2009 this issue).
Natural alexandrite contains water, whereas most synthetic
alexandrite results from melt growth and is therefore anhydrous. The difference is clearly seen using infrared spectroscopy (Stockton and Kane 1988). The same technique
can be applied to synthetic emeralds. Hydrothermally
grown emeralds, although they contain water, always show
small differences compared to their natural counterparts
in the presence, speciation, and topological orientation of
water (see, for example, Schmetzer 1989; Bellatreccia et al.
2008), as revealed by the presence or absence of certain
infrared absorption spectral features. Nondestructive, rapid
identification of mineral inclusions within faceted
gemstones by Raman microspectroscopy (Fritsch and
Rossman 1990) can indicate whether the stone was grown
in nature or the laboratory. Chemical fingerprinting by
laser ablation–inductively coupled plasma–mass spectrometry (LA–ICP–MS) can help to distinguish a natural from
a synthetic origin for various gem species and varieties
(Günther and Kane 1999). The identification of synthetic
diamonds is aided by methods such as visible light, infrared,
and photoluminescence spectroscopy (Shigley 2005).
Conclusions
Man-made gemstones have a legitimate place in the market.
The concern is not the manufacture of these scientific
marvels, but the unscrupulous selling of them as natural
stones. As technological innovation continues to produce
extraordinary synthetic diamonds and synthetic colored
gemstones, research facilities around the world will
continue meeting the identification challenges they present
with practical and advanced analytical testing methods.
By doing so, public trust in the authenticity of gemstones
and jewelry will be maintained.
172
J une 2009
Table 2
A
B
Chronology of the Synthesis of Major Gemstones
Approximate
year of
Synthetica
­availability
gemstone
in quantity
Chemical
formula
Manufacturing
technique
1885
1887
1905
1910
1910
1935c
1947
1948
1950
Ruby (Geneva)
Rubyb (Frémy and Feil)
Ruby
Sapphire
Spinel
Emerald
Star ruby and sapphire
Rutiled
Quartz
Strontium titanate
(not sphene) a,d
Rubyd,e,f
(Remeika U.S. patent)
Emerald
YAGa (yttrium
aluminum “garnet”)
Al2O3
Al2O3
Al2O3
Al2O3
MgAl2O 4
Be3Al2Si6O18
Al2O3
TiO2
SiO2
Crucible (melt)
Flux (solution)
Verneuil (melt)
Verneuil (melt)
Verneuil (melt)
Flux (solution)
Verneuil (melt)
Verneuil (melt)
Hydrothermal (solution)
SrTiO3
Verneuil (melt)
Al2O3
Flux (solution)
Be3Al2Si6O18
1970
Diamondd,e,g
C
1972
1973
1974
1974
1975
Cu2+ Al6 (PO4) 4 (OH) 8.4H2O
BeAl2O 4
SiO2.nH2O
SiO2
SiO2
1976
1976
Turquoise
Alexandrite
Opalh
Citrine (quartz)
Amethyst (quartz)
GGGa (gadolinium
gallium “garnet”)
Lapis lazulia,i
Cubic zirconiad
1976
Alexandrited
BeAl2O 4
1978
1981
Corala
CaCO3
Be3Al2Si6O18
Hydrothermal (solution)
Czochralski pulling
(melt)
High Pressure and high
temperature (solution)
Ceramic
Flux (solution)
Aqueous solution
Hydrothermal (solution)
Hydrothermal (solution)
Czochralski pulling
(melt)
Ceramic
Skull Melting (melt)
Czochralski pulling
(melt)
Ceramic
Hydrothermal (solution)
Al2O3
Flux (solution)
Cu2CO3 (OH) 2
BeAl2O 4
Aqueous Solution
Zone (melt)
Be3Al2Si6O18
Hydrothermal (solution)
MgAl2O 4
Al2O3
SiO2
Flux (solution)
Hydrothermal (solution)
Hydrothermal (solution)
SiO2
Hydrothermal (solution)
Al2O3
Hydrothermal (solution)
SiC (6H polytype)
Sublimation (vapor)
C
CVD (chemical vapor
deposition)
1955
1963
1965
1968
C
1975
D
Aquamarine e
Orange and
blue sapphire
Malachite
Cat’s-eye alexandrite
Red beryl (and
various other colors)
Spinel
Ruby
Pink quartz
Ametrine (citrine and
amethyst quartz)
Sapphire
(various colors)
Moissanite j
(silicon carbide)
1982
1983
1987
1988
1989
1993
1994
1994
(A) This large “nail-head spicule” in a
Biron hydrothermal synthetic emerald
consists of a cone-shaped void that is filled with fluid
and a gas bubble. Although not visible at this viewing
angle, the spicule is capped by a poorly developed,
ghost-like phenakite crystal. Dark-field illumination,
magnified 50x. (B) This Ramaura flux-grown synthetic
ruby displays characteristic, nearly straight, parallel
growth bands, which at some viewing angles exhibit
unusual iridescence. In this view, the very slight
differences in angle between facets cause the growth
features to be iridescent in one and not in the others.
Dark-field illumination, magnified 50x. (C) The shiny,
metallic appearance of platinum is very evident in this
large, thick, angular platinum inclusion in a Chatham
flux-grown synthetic blue sapphire. Dark-field and
fiber-optic illumination, magnified 35x. (D) The finger­
print appearance of this healed fracture in a flux-grown
synthetic sapphire is due to the capture of some flux
during crystal growth. Dark-field illumination, magnified
30x. Photomicrographs by Robert E. K ane
Figure 5
E lements
1995
1997
2003
Diamond
Y3Al5O12
Gd3Ga5O12
(Na,Ca) 8 (Al,Si)12O24 (S,SO 4)
ZrO2 + stabilizer
The majority of the 1885–1978 data were adapted from Nassau (1980).
a Gemologists use the term “imitation” for man-made materials that do not have a naturally occurring equivalent
in large crystals (e.g cubic zirconia) or do not share chemistry and crystallographic structure with a natural
counterpart (e.g. strontium titanate, YAG, GGG, lapis lazuli, and coral).
b Only small flux-grown ruby crystals (>3 mm)
c Nassau (1980) reported 1950; however, several gemologists published work on IG-Farben (“Igmerald”) synthetic
emeralds in 1935. In 1848 J.J. Ebelman reported success in growing flux synthetic emeralds. However, it was
Hautefeuille and Perrey’s 1888 and 1890 published reports that forged the path for all later flux emerald growth.
d Process developed for potential technological use
e Experimental production only
f Modern flux-growth of large ruby crystals
g In 1954 General Electric succeeded in synthesizing very tiny (150-micron) diamonds, which were not of gem
quality. Although only experimental and not commercially available, 1970 marked the first time that “sizable”
faceted synthetic diamonds had been synthesized by General Electric. In 1985, Sumitomo Electric Industries
(Japan) began marketing for industrial uses yellow synthetic diamond crystals in sizes up to 2 carats. By 2008,
faceted HP–HT synthetic diamonds were available for sale around the world in many colors, including colorless,
yellow, brown, blue, pink, red, purple, and green.
h The chemical formula listed is for natural opal. Some man-made opals do not contain H O (or as much as natural
2
opals do) and contain ZrO2. Thus they are considered imitations (not synthetics) by some gemologists.
i The chemical formula listed is for natural lapis lazuli, which is an aggregate of several minerals, predominantely
polycrystalline lazurite.
j Synthetic silicon carbide has been produced for technological uses for many decades. However, 1997 marked
the first time large, near-colorless crystals were grown for use as faceted imitation diamonds.
173
J une 2009
REFERENCES
Barnes WH (1950) An electron microscopic
examination of synthetic tourmaline
crystals. American Mineralogist 35: 407-411
Bellatreccia F, Della Ventura G, Piccinini
M, Grubessi O (2008) Single-crystal
polarised-light FTIR study of an historical
synthetic water-poor emerald. Neues
Jahrbuch für Mineralogie, Abhandlugen
185: 11-16
Devouard B, Notari F (2009) The identification of faceted gemstones: From the
naked eye to laboratory techniques.
Elements 5: 163-168
Emmett JL, Scarratt K, McClure SF, Moses
T, Douthit TR, Hughes R, Novak S, Shigley
JE, Wang W, Bordelon O, Kane RE (2003)
Beryllium diffusion of ruby and sapphire.
Gems & Gemology 39: 84-135
Fritsch E, Rondeau B (2009) Gemology:
The developing science of gems. Elements
5: 147-152
Fritsch E, Rossman GR (1990) New technologies of the 1980s: Their impact in
gemology. Gems & Gemology 26: 64-75
Günther D, Kane RE (1999) Laser ablation–inductively coupled plasma–mass
spectrometry: A new way of analyzing
gemstones. In: Proceedings of the Third
International Gemological Symposium,
San Diego, June 21–24, 1999. Gems &
Gemology 35: 160-161
Jones JB, Sanders JV, Segnit ER (1964)
Structure of opal. Nature 204: 990-991
Kane RE, Liddicoat RT Jr (1985) The Biron
hydrothermal synthetic emerald. Gems
& Gemology 21: 156-170
Muhlmeister S, Fritsch E, Shigley JE, Devouard
B, Laurs BM (1998) Separating natural
and synthetic rubies on the basis of traceelement chemistry. Gems & Gemology
34: 80-101
Nassau K (1980) Gems Made by Man. Chilton
Book Company, Radnor, PA, 364 pp
Rossman GR (2009) The geochemistry of
gems and its relevance to gemology:
Different traces, different prices. Elements
5: 159-162
Schmetzer K (1989) Types of water in natural
and synthetic emerald. Neues Jahrbuch
für Mineralogie Mh, pp 15-26
Shigley JE (ed) (2005) Gems & Gemology
in Review: Synthetic Diamonds. Gemological
Institute of America, Carlsbad, CA, 294 pp
NanoGeoScience, University
of
Stockton CM, Kane RE (1988) The distinction
of natural from synthetic alexandrite by
infrared spectroscopy. Gems & Gemology
24: 44-46
Sunagawa I (2005) Crystals: Growth,
Morphology, Perfection. Cambridge
University Press, Cambridge, UK, 295
pp
Taran MN. Lebedev AS, Platonov AN (1990)
An optical-spectroscopic study of synthetic
iron-containing tourmalines. Izvestiya
Akademii Nauk SSSR, Neorganicheskie
Materialy 26: 1025-1030
Taran MN, Lebedev AS, Platonov AN (1993)
Optical absorption spectroscopy of synthetic
tourmalines. Physics and Chemistry of
Minerals 20: 209-220
Taran MN, Langer K, Platonov AN (1996)
Pressure- and temperature-effects on
exchange-coupled-pair bands in electronic
spectra of some oxygen-based iron-bearing
minerals. Physics and Chemistry of
Minerals 23: 230-236
Trill H, Eckert H, Srdanov V, Stucky GD
(1999) Magnetic iron clusters in sodalites.
In: Materials Research Society Symposium
Proceedings Series 577, San Francisco,
April 5–9, 1999
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E lements
174
J une 2009
Laboratory-Treated
Gemstones
James E. Shigley and Shane F. McClure*
1811-5209/09/0005-0175$2.50 DOI: 10.2113/gselements.5.3.175
T
reatment processes to improve the color, appearance, and/or durability
of certain gemstones have been used for hundreds of years, and their
variety, sophistication, and application within the jewelry trade have
increased over the past several decades. Whether or not these enhancement
processes are considered acceptable trade practices, their use must legally
be disclosed at the time of gemstone sales. Disclosure of treatment information
requires that treated gems be correctly identified by gemologists and gemtesting laboratories. Treatment detection is based upon careful documentation
of the properties of gem materials, including the use of advanced
nondestructive techniques for obtaining chemical and spectral data.
accepted in the jewelry trade, especially the introduction of foreign
materials by high-temperature
diffusion processes. Nonetheless,
whether considered traditional or
not, all treated gems require complete
disclosure at the time of sale.
Accurate identification of treated
gems is essential for this disclosure. However, several challenges
confront this goal. There is variability in the response of starting
materials to treatment processes—
the final result may depend on
Keywords : gemstone, treatment, color, clarity, appearance, identification
parameters such as the nature,
speciation, concentration, and
INTRODUCTION
valence state of trace elements, or on the kind of clarity
A treatment is any artificial process by which the appear- features that are intended to be modified or hidden. This
ance of a gem can be improved—for example, heating a problem is compounded by the possibility of several different
cloudy sapphire to make it transparent blue, irradiating a treatment methods being used on a single gemstone (e.g.
light pink tourmaline to turn it red, or impregnating an
irradiation followed by heating) and the frequent lack of
emerald with resin to hide its fractures. Some treatments detailed information about the methods themselves.
merely copy (and accelerate) processes observed in nature,
For gemological researchers, one of the most important
whereas others are entirely devised by man. Since the
1990s, laboratory treatment has become increasingly preva- ways to recognize treated gems is through documentation
lent for most of the major gem materials. Although treat- of gem samples before and after a treatment procedure,
thus allowing comparison of changes in properties brought
ment is usually undertaken for legitimate commercial
about by the process. When these changes are fully underreasons, the resulting gem materials can enter or pass
stood, treatment identification criteria may be refined, and
through the jewelry trade without full disclosure of how
even simplified. Because new gem treatments may not be
there were treated, and with the possible intent to mislead
fully disclosed initially, the task of identification often takes
or defraud potential buyers.
on an aspect of “forensic gemology.”
The practice of treating gems to improve their color or
This article will review some of the most important gem
apparent clarity extends back many centuries (Nassau 1994).
treatment methods in use today, with examples of gems treated
In recent decades, the range of gem treatment methods
by these methods, and will provide some insights into how
has become greater and, today, a variety of treated gem
these treatments may be detected.
materials can be found in the jewelry marketplace. This
proliferation has resulted in part from the growing consumer
Historical perspective
demand for less-expensive gem materials, much of which
is driven by marketing efforts such as television programs on Gem treatments have been used since ancient times, with
jewelry shopping. Advances in existing treatment techniques,
descriptions of simple methods extending back two
such as controlled-atmosphere heat treatment, and tech- millennia for materials such as quartz and chalcedony.
nology transfer from other industries (most recently from These early methods included the use of shiny metal foils
coating technologies) have also provided a wider range of or colored stains placed behind or on the back of fashioned
products for jewelry use. Within the production of most gem gemstones to make them appear more brilliant or colored
deposits, there is normally an abundance of poor-quality
when set in a mounting. The application of oils or other
material that can be made saleable via these treatments.
liquids to make them more shiny or transparent and the
Some treatments of gemstones have been considered “traditional” practices because of their historical use (such as
the heating of aquamarine), while others are much less
* Gemological Institute of America (GIA)
5345 Armada Drive, Carlsbad, CA 92008-4602, USA
E-mail: [email protected]; [email protected]
E lements , V ol . 5,
pp.
175–178
dyeing or staining with organic or inorganic substances to
change their color were popular treatments.
The development of geology and mineralogy in the late
Middle Ages was accompanied by the use of more-sophisticated treatment methods (principally better controlled
heating) on gems such as corundum (ruby and sapphire),
topaz, zircon, and amethyst. Most current gem treatments
were known and practiced by the end of the nineteenth
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century. One exception was the use of irradiation methods,
which followed the discovery of X-rays in 1895 and radioactivity in 1896. Commercial irradiation of gems such as
diamond began in the early 1950s, although experiments
on the effects of exposing gems to sources of radiation
(such as radium compounds) to change their color were
being conducted as far back as 1905.
Gem treatment methods
Gem treatments can be grouped into three general categories:
those that change the color, improve the appearance, mostly
the apparent clarity, and improve the durability of the gem
material (McClure and Smith 2000; Smith and McClure 2002).
Heating
Heating in a controlled oxidizing or reducing atmosphere
can lead to changes in the valence states of coloring agents
such as the transition metals, or to the creation or destruction of color centers in the atomic lattice of the material.
Heating is used to improve the transparency of gems, to
create or remove the inclusions that are responsible for asterism
or other optical effects, or to deliberately crack the gemstone
to permit better bleaching and the addition of color by dyeing.
Heating can be very rudimentary, for example with a blowpipe or a simple wood fire. Currently, electrical and gas furnaces
with atmosphere control are more common, particularly
for corundum, with heating temperatures reaching 1800°C.
Although previously performed in research laboratories,
the annealing of some gem diamonds at very high temperatures and confining pressures to improve their color began
on a commercial scale only in 1999. This high-pressure
and high-temperature (HP–HT) process was briefly described
by Shigley (2005).
Heat treatment of corundum has been generally viewed as
an accepted, “traditional” practice. However, most people
outside the gemstone industry are not aware that this treatment is capable of producing some very significant color
changes in corundum. For example, some translucent white
sapphires (known as “geuda”) can be changed to transparent
blue gems (Fig. 1) in a reducing atmosphere by dissolving
submicroscopic inclusions of rutile (TiO2). This releases Ti
into the structure and retains the iron as Fe2+, leading to
Fe2+ – Ti4+ charge transfer, which causes the blue color. On
the other hand, pale blue sapphires can be made nearly
colorless in an oxidizing atmosphere by turning Fe2+ into
Fe3+. This destroys the charge transfer and can remove an
unwanted blue component in pink sapphires and rubies.
The same process can darken light yellow sapphires by
converting much of the Fe2+ in the stone into Fe3+ (Fig. 1).
Heat treatment of other gemstones is common, although
usually at much lower temperatures. For example, the green
component in aquamarine can be removed to make a more
desirable blue color, and brown zoisite can be changed to
violet-blue tanzanite. These effects are caused by a valence
change (from Fe3+ to Fe2+ for beryl) or by destruction of
color centers (a defect in the structure of a material that
causes it to selectively absorb portions of the visible light
spectrum to produce color). In some cases, annealing is
used to lighten the color of materials by returning electrons
to their original lattice site, thereby destroying the color
center and resulting color tint. Because gem minerals can
be subject to heating naturally under geological conditions,
it is often difficult, if not impossible, to distinguish artificial from natural heating for some gem materials.
Diffusion of Chromophores
Heating accompanied by the diffusion of trace elements
from external sources into the body of the gemstone (only
corundum and feldspar have been treated so far) can
produce an artificial color. In this process, atoms move
from the faceted outer surfaces of the gemstone inward.
The color produced by this diffusion may penetrate only
a short distance, as with titanium in corundum giving a
blue color, or it may extend throughout the stone, as with
beryllium in the same gem. The depth of penetration is
governed by the ion being diffused, the heating temperature, and the length of time the stone is heated. In late
2001, the jewelry trade was confronted with a new type of
diffusion treatment when it was discovered that traces of
beryllium (several tens of parts per million) could be diffused
faster and deeper than previously used trace elements
(Emmett et al. 2003). This now-prevalent treatment for
gem coundum adds a yellow-to-orange component due to
the hole center caused by the replacement of Al3+ by Be2+
(Fig. 2). This created a major problem for identification in
gem laboratories, which is now dealt with through the
detection of Be via laser ablation–based chemical analysis
methods such as laser ablation–inductively coupled plasma–
mass spectrometry (LA–ICP–MS) or laser-induced breakdown spectroscopy (LIBS).
Irradiation
Exposure to electromagnetic radiation can eject electrons
from atoms and, more rarely, break bonds, moving atoms
slightly inside a gem material. This adds color by creating
color centers, as in diamonds (Shigley 2008). A whole range
of ionizing radiations can be used. However, commercial practice
is essentially limited to gamma rays, irradiation by electrons,
and neutron irradiation, because these can penetrate throughout
the volume of the gem to create uniform coloration.
Many of the colors of sapphire can be created or improved
by heat treatment. This image was taken in the office of
the company that treated these stones in Sri Lanka. The bottom row
shows the colors of the sapphires before treatment, and the top row
shows similar material after treatment. The two groups on the far right
are examples of “geuda” sapphire, a milky white or light-colored
material that can be heated at high temperature (1600–1700°C) to
give a transparent blue color. Photo by Shane McClure, copyright GIA
Figure 1
E lements
In the 1970s and 1980s, radiation exposure to produce the
saturated blue colors in topaz was widespread (Fig. 3).
Curiously, the exact nature of the color center responsible
is still unknown, and a nondestructive method to detect the
treatment remains elusive. A small number of other natural
minerals have been irradiated for color: yellow to brown
quartz, pink tourmaline, yellow beryl, and purple fluorite
are a few examples.
There is no general theory that helps to differentiate
natural irradiation from its human-produced counterpart,
which, in the case of some artificially irradiated gems, comes
very close to a simple replication of a naturally occurring
process. Thus, recognizing man-made irradiation in gem
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J une 2009
materials is a challenge. Limited depth of penetration, in
particular if the induced color follows the faceted shape of
the gem, is one of a small number of criteria available.
Also, with a few natural exceptions (ekanite, some zircons),
any gemstone that displays detectable residual radioactivity
is very likely to have been artificially irradiated.
Chemical Treatments
Chemical bleaching, dyeing, and coating are treatments
used to remove undesired existing colors or to create new
colors on surfaces and along open fractures. If a bright
color is always a plus, grey or brown additional colors or
patches are often considered undesirable. This is particularly true for jadeite jade and pearls. A range of chemicals
are used to dissolve “impurity” minerals in the jadeite jade
rock, from plum juice (an early attempt) to acids or other
secret products. However, as it damages the structure of
the rock, bleaching must be followed by impregnation (see
below). Many natural and cultured pearls are bleached with
hydrogen peroxide to eliminate dark spots due to extra
organic matter so that they take on a whiter appearance.
(Fig. 4b). In some cases, they also exhibit iridescence. In
addition, the optical absorption spectrum of the coated
gemstone will likely not match what is expected for the
material, or the chemistry of the surface may reveal the
foreign elements. However, visually detecting such coatings
becomes much more difficult if the gemstone is small in
size, if it is mounted in a piece of jewelry, or if the coating
material is colorless.
Fracture Filling
Filling cavities or surface-reaching breaks with liquids
(colorless or colored) or melted solids to hide their visibility
(and possibly to add weight or to enhance color) is another
common technique. The filling material should ideally
have an index of refraction similar to that of the host gem
in order to avoid reflection at the fractures and to reduce
unwanted light scattering (Kiefert et al. 1999). A close
match makes fractures almost invisible, thus resulting in
an apparent enhancement of clarity. If the dispersion
curves of the host gemstone and filling material intersect,
this produces the so-called “flash effect”— bright colors
Coating
Coatings have become a more serious problem for gemologists in recent years, as many processes developed for the
electronics and optics industries have been applied to a
number of gem materials. Chemical or physical vapor deposition, for example, can help add very thin colored films,
sometimes themselves quite complex multilayers, on top
of just about any kind of gem (Schmetzer 2006). This is
really not a problem when the final product displays
unusual colors and has no natural equivalent (e.g. an iridescent “mystic topaz”); however, it is problematic if the result
closely resembles a natural gem. On occasion, faceted
diamonds are coated with a thin layer of a foreign substance,
such as calcium fluoride and metals, to change their color
(Fig. 4a). Application of a small amount of a blue substance
to specific areas on the surfaces can lessen the visibility of
a yellow body color so that the diamond appears colorless.
Coatings can often be recognized because they are softer
than the underlying gemstone and thus display evidence
of scratches and other surface damage in reflected light
A
Treated blue topaz (bottom) is typically produced by
irradiating abundant colorless material (top),
as this blue color seldom occurs naturally. There is no known nondestructive method to detect irradiation treatment in topaz.
Photo by Robert Weldon, copyright GIA
Figure 3
A
B
B
(A) In an early experiment on beryllium diffusion, a pink
sapphire was cut in half, keeping one half as a control.
One half was heated for approximately 20 hours to diffuse beryllium
into the material, turning it into a pinkish orange color due to the
creation of a hole center that altered the selective absorption of light
by the sapphire. Photo by Maha Tannous, copyright GIA (B) In cases
such as this sapphire, the color produced by diffusion treatment does
not penetrate very far into the stone. The surface-conforming color
zone in cases such as this sapphire can be the key to identifying this
type of treatment. Photomicrograph by Shane McClure, copyright GIA
Figure 2
E lements
(A) Coating diamonds to change their color has been
done for centuries, but the practice has recently escalated
due to wider availability of more sophisticated coating techniques.
Off-colored or pale-colored diamonds are now often coated to make
them appear pink, red (photo), yellow, blue, or other colors. Photo by
Don Mengason, copyright GIA (B) Diamond coatings, while more
durable than in the past, can still be scratched or abraded, making
them easy to detect by observations under magnification, if one is
aware that he or she must look for them. Photomicrograph by Shane
McClure, copyright GIA
Figure 4
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J une 2009
seen along the filled factures when they are observed
almost end-on against a light or dark background (Fig. 5b).
This is actually the same optical phenomenon as colored
Becke lines, well known to those who have had to determine
the index of refraction of mineral grains in reference liquids.
Of particular concern today is the filling of fractures in
ruby with a lead-based glass of high refractive index similar
to that of corundum. This process can transform opaque
and highly fractured red corundum with no gem value into
translucent and even transparent gem ruby (Fig. 5a). Easily
identified through flat bubbles in the cracks or through
dispersion-induced colors, this treatment is very sensitive
to jewelry-repair procedures (Milisenda et al. 2006), as heating
during repair can damage the filler glass and the appearance
of the treated ruby.
Impregnation
Impregnation with a foreign substance (such as resin or
wax) to help stabilize a porous gem material can improve
its appearance and make it more durable. This practice puts
on the market materials that otherwise would not be able
to withstand normal use. A good example is turquoise, which
can be very porous and chalk-like. In the most extreme
cases, gray, powdered turquoise is embedded in a bright blue,
plastic matrix. This practice can be extended to many other
materials, such as malachite and lepidolite-rubellite rock.
As mentioned above, chemical bleaching damages the
structure of jadeite. It must then be impregnated with a
wax, resin, or polymer (commonly polystyrene) with an
appropriate index of refraction to fill cavities and gaps
between the individual grains of the jadeite (Fritsch et al.
1992). This procedure restores optical continuity and
improves mechanical resistance and durability (Fig. 6a).
Infrared spectroscopy is useful for detecting the presence
of these organic impregnation materials (Fig. 6b). Detection
of jade treatment is of great importance because of the very
high market value of natural jadeites with an intense green
color and high translucence.
Conclusion
Treated gem materials are now routinely encountered in
the jewelry marketplace. Some are quite crude and unnatural in appearance and are easily recognized by gemologists,
whereas others can deceive even gem experts. However,
the progressive development of the atomic-scale understanding of many processes, sometimes providing new
detection techniques (such as laser-ablation and surfaceanalysis methods), helps the gemologist to maintain the
ability to detect treatments.
The number of treated gems in the marketplace is likely to
increase due to the the growing demand for gemstones in
many parts of the world, a demand that exceeds the supply
of high-quality, untreated, natural gems. Detection of gem
treatments is important for encouraging proper disclosure
REFERENCES
Emmett JL, Scarratt K, McClure SF, Moses
T, Douthit TR, Hughes R, Novak S, Shigley
JE, Wang W, Bordelon O, Kane RE (2003)
Beryllium diffusion of ruby and sapphire.
Gems & Gemology 39: 84-135
Fritsch E, Wu S-TT, Moses T, McClure SF,
Moon M (1992) Identification of bleached
and polymer-impregnated jadeite. Gems
& Gemology 28: 176-187
Kiefert L, Hänni HA, Chalain JP, Weber W
(1999) Identification of filler substances in
emeralds by infrared and Raman spectroscopy. Journal of Gemmology 26: 501-520
E lements
A
B
(A) High-lead-content glass is used to fill highly fractured
rubies, making them much more transparent than they
were when mined. This treatment works because of the close match
in the indices of refraction of the glass and ruby matrix. Photo by Don
Mengason, copyright GIA (B) The presence of this lead glass can usually
be detected under a microscope by observing the blue and orange
dispersion colors—equivalent to a colored Becke line in classical optical
crystallography— from the filled areas, a phenomenon that gemologists
call a “flash effect”. Photomicrograph be Shane McClure, copyright GIA
Figure 5
A
B
(A) Jadeite jade is often stained brown naturally by
various minerals containing ferric iron, present in the
geological environment in which the rock is found. These minerals
and this undesirable color component can be extracted or “bleached
out” with acids, leaving only green and white jadeite. This harsh
treatment damages the structure of the jadeite rock, making it
necessary to impregnate the material, typically with resins, to restore
both the appearance and structural integrity. Here we see two halves
of the same jade sample, one before treatment (left) and the other
after bleaching and impregnation (right). Photo by Tino Hammid,
copyright GIA and Tino H ammid (B) Infrared absorption spectra are very
useful for detecting the polymers used to impregnate bleached
jadeite jade. Here we see the spectrum of untreated jadeite (below)
compared to that of impregnated jadeite (above), which shows
bands due to the C-H stretching mode of the impregnation material
between approximately 2800 and 3100 cm -1.
Figure 6
of treated gem material at the time of sale and for protecting
consumers from being charged more than an item is worth.
Recognizing treatments of gem materials is now the principal focus of research at many gemological organizations
around the world.
McClure SF, Smith CP (2000) Gemstone
enhancement and detection in the 1990s.
Gems & Gemology 36: 336-359
Shigley JE (2005) High-pressure and hightemperature treatment of gem diamonds.
Elements 1: 101-104
Milisenda CC, Horikawa Y, Manaka Y, Henn
U (2006) Rubies with lead glass fracture
fillings. Journal of Gemmology 30: 37-42
Shigley JE (ed) (2008) Gems & Gemology
in Review: Treated Diamonds. Gemological
Institute of America, Carlsbad, California
Nassau K (1994) Gemstone Enhancement,
2nd edition. Butterworth-Heinemann,
New York, pp 6-25
Smith CP, McClure SF (2002) Chart of
commercially available gem treatments.
Gems & Gemology 38: 294-300
Schmetzer K (2006) Surface coating of
gemstones, especially topaz - A review
of recent patent literature. Journal
of Gemmology 30: 83-90
178
J une 2009
Pearls and Corals:
“Trendy Biomineralizations”
Jean-Pierre Gauthier1 and Stefanos Karampelas2
1811-5209/09/0005-0179$2.50 DOI: 10.2113/gselements.5.3.179
C
orals and pearls are “organic gems” produced by living beings.
These esthetic “biomineralizations” are attractive for their color
and the optical effects resulting from their structure.
Pearls are secreted by mollusks,
such as bivalves, gastropods, and,
very rarely, cephalopods (Landman
et al. 2001). They were initially, and
are still occasionally today, fished
Keywords: coral, pearl, biomineralization, cultured pearls, endangered coral species
in nature from various saltwater
bivalves (for example, Pinctada spp.
in the Philippines, Australia,
Pearls and corals are good examples of important gems
formed directly through biological processes, i.e. biominer- Persian Gulf, etc.). More rarely, they are retrieved from
alization (Dove et al. 2003). Pearls are valued for their appear- gastropods (for example, Strombus gigas in the western
ance, which is a consequence of their internal structure. Atlantic Ocean) and from freshwater bivalves (for example,
Margaritifera margaritifera in Europe and more than 300
They raise the question of how nanoelements are put
species belonging to the Unionidae family in the United
together in a regular, yet sometimes very complex, manner.
States). However, most pearls on the market today are
This architecture gives rise to desirable optical effects, such
as the nacreous aspect of most pearls (Fig. 1) and the flame cultured—that is, they are formed through human intervention by graft transplantation, with or without simultastructure of pearls from certain gastropods (e.g. Strombus
neous solid nucleus implantation, on mollusks raised in
gigas). On the other hand, coral is mostly prized for its
pink-to-red color, which arises from absorption by poly- farms. The cultured pearl industry uses mollusks from
either freshwater (Hyriopsis spp., such as Japanese Biwa
acetylenic pigments (mainly in Corallium spp.). The same
family of pigments is also responsible for the color of some cultured pearls) or saltwater (Pinctada spp., such as Tahiti
cultured pearls, and very rarely Pteria sterna; Strack 2006),
pearls. The nature of the bridge between the organic
all of which have a nacreous appearence. Because of this,
pigments and the mineral and/or organic matter of these
the public is more familiar with nacreous cultured pearls.
gems is an unsolved riddle. This bridge plays an important
These are composed of a network made of aragonite and
role, among other factors, in the stability of color.
Understanding better these biomineralization processes organic matter deposited in concentric layers. The organic
matter of pearls is a mixture of β-chitin and an assemblage
will help to further develop cultured pearl production and
of acidic glycoproteins, and was formerly known as conchymake their cultivation more efficient.
olin (Levi-Kalisman et al. 2001). Each layer is composed
In addition to their scientific interest, these gems also have
economic appeal. Although pearls have been used for
millennia, they are enjoying a revival due to an increase in
cultured pearl production, particularly from the larger
Pinctada species, since World War II (Shor 2007). Japan, Australia,
Indonesia, and the Philippines are the main sources of
white and golden South Sea cultured pearls, while French
Polynesia is a supplier of black Tahitian cultured pearls
(Strack 2006). In recent years, China has developed into a
giant producer of freshwater cultured pearls (Hyriopsis spp.).
About 1500 tons, of which 75 tons (or 375 millions carats)
are of gem quality, are produced annually in China(Fig. 2).
This alone represents 95% of the pearls in today’s market.
Corals are under the spotlight because, even though their
colors are in fashion, some corals are endangered species
(e.g. Stylaster spp.) and are protected by international laws.
Currently, there are no such restrictions on Corallium, one
of the most important coral genuses in gemology (Fig. 3).
1 Centre de Recherche Gemmologique
2, rue de la Houssinière, BP 92208
44322 NANTES Cedex 3, France
E-mail: [email protected]
2 Gübelin Gemmological Laboratory
Maihofstrasse 102, 6006, Lucerne, Switzerland
E-mail: [email protected]
E lements , V ol . 5,
pp.
179–180
Pearls, as well as coral, are the product of biomineralization,
that is, they are composed of minerals deposited by
living organisms. The nacreous appearance is the result of the curved
grating of aragonite and organic matter forming concentric layers.
Pteria sterna cultivation in the Sea of Cortez, Mexico, delivers an annual
production of a mere 3.5 kg of cultured saltwater pearls (shown here)
with strong “body” and “secondary” colors (diameter of the pearls in
the photo is ~9 mm). Photograph by Perlas del Mar de Cortez, Guaymas, Mexico
Figure 1
179
J une 2009
Freshwater cultured pearls produced in China represent
95% of the market. They are cultivated in mollusks
belonging to Hyriopsis spp., and they occur naturally in white, grey,
yellow, orange, pink and purple colors. Various combinations of tone
and saturation yield a broad range of color appearances. These pearls
are colored by a mixture of short polyacetylenic pigments. Different
colors are explained by different mixtures and not by the change of a
single pigment. The pearls in the photo are between 6 and 8 mm in
diameter. Photograph by stefanos karampelas, gübelin gemmological laboratory
Figure 2
Corallium rubrum is the most important coral used in
jewelry, but it is not protected yet. It is colored by a
mixture of short polyacetylenic pigments. Photograph by Gérard Rivoire
Figure 3
REFERENCES
Dove PM, De Yoreo JJ, Weiner S (2003)
Biomineralization. Reviews in Mineralogy
and Geochemistry 54, The Mineralogical
Society of America, Chantilly, VA, 381 pp
of highly organized polygonal aragonite platelets (about 3
to 5 microns across and 0.4 to 1 micron thick) wrapped in
“conchyolin.” This “bricks and mortar” structure is responsible for nacre’s high strength and fracture toughness. If
the layers are regular enough, they can produce iridescence
colors. Known as secondary colors, these can add considerable value to a pearl, and they are particularly spectacular
if a dark body color contrasts with these optical effects
(Fig. 1). Similar physical phenomena are found in other
mineralogical materials, such as ammolite (a fossil shell),
rainbow moonstone (a feldspar), and Mexican rainbow
obsidian. The nacreous surface layers of pearls are usually
incomplete, resulting in beautiful terrace-like arrangements, usually in the form of “fingerprints,” as seen under
the microscope. This texture usually generates a gritty
feeling to the teeth, which is used to separate pearls from
their imitations. Current questions include the instigation
of the formation of natural pearls, and the nature, role,
and index of refraction (which is required for optical
modeling) of the organic matter.
The term “coral” refers to many Anthozoa and to some
Hydrozoa (marine invertebrates) that develop colonies
forming a common calcareous skeleton, sometimes building
huge reefs in shallow seawater (Fig. 3). Only the skeleton
is used as gem material. Determining a coral species through
simple observation of a fashioned fragment is a challenge
to the gemologist, one familiar to paleontologists. The
Corallium genus is by far the most important for jewelry,
although a surprisingly wide variety of other corals have
been fashioned and often treated. Indeed, the major attraction is the body color. The internal texture is generally less
visible and more subdued, but it is very useful to separate coral
from its imitations. The Corallium pink-to-red colors are
caused by a mixture of unsubstituted short polyenic
pigments—oligomers of polyacetylene—and not a carotenoid, as previously believed (Karampelas and Fritsch 2007).
The same family of pigments has been found to color a
number of pearls, including freshwater cultured pearls
(Hyriopsis spp.; Karampelas et al. 2009a). Much remains to
be done to fully identify pigments in the untreated gems.
Due to their current popularity, the colors of pearls and corals
have been modified by dyeing or bleaching, thus producing
a wider range of appearances (e.g. Smith et al. 2007). The
pigments used for treatment give totally different Raman
signals. Raman spectroscopy may also help identify some
endangered coral species (e.g. Stylaster spp.; Karampelas et
al. 2009b).
Pearls and corals are complex materials with gemological
properties and a commercial value influenced by many
parameters. Living beings control both the mineral structure
and the presence of organic pigments. Gemologists are only
starting to scratch the surface of the biological world.
Karampelas S, Fritsch E, Rondeau B, Andouce
A, Métivier B (2009b) Spectroscopic
identification of the endangered pinkto-red Stylaster genus coral. Gems &
Gemology, 45: 48-52
Karampelas S, Fritsch E (2007) Letter to the
editor: Pigments in natural-color corals.
Gems & Gemology 43: 96-97
Landman NH, Mikkelsen PM, Bieler R,
Bronson B (2001) Pearls – A Natural
History. Harry N. Abrams Publications,
New York, NY’ 232 pp
Karampelas S, Fritsch E, Mevellec J-Y,
Sklavounos S, Soldatos T (2009a) Role of
polyenes in the coloration of cultured
freshwater pearls. European Journal of
Mineralogy 21: 85-97
Levi-Kalisman Y, Falini G, Addadi L, Weiner
S (2001) Structure of the nacreous organic
matrix of a bivalve mollusk shell examined
in the hydrated state using cryo-TEM.
Journal of Structure Biology 135: 8-17
E lements
180
Shor R (2007) From single source to global
free market: the transformation of the
cultured pearl industry. Gems & Gemology
43: 200-226
Smith CP, McClure SF, Eaton-Magaña S,
Kondo DM (2007) Pink-to-red coral: a
guide to determining origin of color.
Gems & Gemology 43: 4-15
Strack E (2006) Pearls. Rülhe Diebener
Verlag Publications, Stuttgart, 707 pp
J une 2009
International Association of Geoanalysts
http://geoanalyst.org
International Association of Geoanalysts’
Certified Reference Material Programme
IAG CRM-2
President’s Spring Report
Certificate of Analysis:
Central Geological Laboratory Serpentinite MGL- GAS
The beginning of 2009 has brought notable milestones for our Society, and Elements magazine
offers me the perfect vehicle by which to update
both IAG members and the broader geoanalytical
community.
Description of the Sample:
This material was collected from the Naran
Massif in the Khantaishir area of Mongolia. It
was originally prepared, packaged and
certified in December, 1998 by the Central
Geological Laboratory (CGL), Ulaanbaatar,
Mongolia. The material consists of a
homogeneous powder of which 98.5%
passed a 74 µm sieve. The mineralogy of
the sample (in % m/m) has been determined
to be as follows:
95.1 serpentine
2.4 magnetite
1.20 calcite
0.40 plagioclase
0.30 magnesite
0.30 chromite
0.25 goethite
0.15 sericite-muscovite
minor pyrite, pyrrhotite, olivine,
chalcopyrite and amphibole
Mireille Polvé to Step Down as Editor-in-Chief of GGR
Geostandards and Geoanalytical Research (GGR) has
been the official journal of the IAG ever since our
Society was established in 1997. And ever since
that time Mireille Polvé has been one of our journal’s two editors-in-chief. Although Mireille
retired last year from her research position at the
Université Paul Sabatier in Toulouse, she elected
to continue her role with GGR until the completion of the current three-year cycle on which our
organization is based. Everyone associated with
GGR was naturally pleased with her ongoing commitment to the journal.
With the approach of the Geoanalysis 2009 conference in September,
the leadership of GGR is now preparing for the transition to a new
editorial structure. Envisioned is an expanded staffing of the editorin-chief’s department, leading to further reductions in the duration of
the submission-to-press cycle. With Mireille’s departure from the GGR
leadership, special attention is also being focused on assuring the high
scientific quality of the journal, maintaining GGR’s impressive impact
factor (currently 3.00) and further expanding its readership. On behalf
of all of us associated with Geostandards, I wish Mireille all the best for
the future and say “THANKS !!” for the 35 outstanding issues produced
under her leadership.
In Situ Proficiency Testing Scheme Becomes Routine
For the past decade the Geo-PT proficiency testing programme has been
a cornerstone of good laboratory practice for bulk rock analysis laboratories. This well-established programme is now joined by “G-Probe”,
the IAG’s second PT scheme, which supports laboratories active in the
discipline of geochemical microanalysis. Managed by Steve Wilson of
the U.S. Geological Survey’s Denver office, G-Probe organizes twiceannual distributions of materials specifically tailored to the QA (quality
assurance) needs of the in situ microanalytical community. Initially it
is planned that sample distribution will alternate between synthetic
glasses and specially produced pressed powders. Such materials can be
used for the QA needs of both major (e.g. EPMA) and trace element
(e.g. LA–ICP–MS) analytical methods. Further information on both
G-Probe and Geo-PT, including participant application forms, is available from http://geoanalyst.org/.
This material has been produced in units of
100 g packaged in a polyethylene bottle for
delivery to users.
Tables 1 and 2 state the determined
composition of ML-GAS and the associated
expanded uncertainties. A full description of
how these certified values and their
uncertainties have been established can be
found in Kane et al. (2003). Table 3 provides
additional information that is essential for
user laboratories to evaluate their own
results for the CRM in the manner outlined
in ISO Guide 33 (ISO 2000).
Intended uses of this CRM:
This CRM is intended for use in calibration
and quality control by laboratories when
analyzing samples that are matrix-matched
to ML-GAS.
IAG CRM-2 Serpentinite MGL-GAS
Mass fraction or concentration
Certified
Reference Material Programme
Oxide/Element
IAG CRM-3
SiO2
Fe2O3(TOT)
MnO
MgO
LOI
CV
±U
in % m/m
38.54
0.23
8.00
0.22
0.082
0.009
38.22
0.34
13.33
0.14
N
43
44 of Analysis:
Certificate
36
Central Geological Laboratory
Alkaline Granite
42
26 OShBO
MGL-
in mg/kg
Description
of the Sample:
Co
106
3
27
A sample
with a total2780
mass of 40030
kg of the 26
Cr
candidate
CRM was 2300
collected from
Ni
120
26
“Tsagaan
Horoot”
of
Buren
somon
in
the
Sr
7.3
0.4
12
Central
U Province of Mongolia
0.80 following
0.04
12
standard procedures and under the
V
33.4
2.0
10
guidance of field geologists. It was originally
Zn
39
3
12
prepared, packaged and certified in the year
2000 by the Central Geological Laboratory
(CGL), Ulaanbaatar, Mongolia. The material
2. Information
Values
consists of Table
a homogeneous
powder
of which
and
their
93.3% passed
a 63
µmUncertainties;
sieve, while 0.44%
Mass
concentration
was larger
thanfraction
100 µm.orThe
mineralogy of
the Oxide/Element
material (in % m/m) has
been
IV
±U
N
determined to be:
in % m/m
32.2 albite
32.1
0.022
0.007
TiO
2 potassium feldspar
31.5
Al
0.475
0.020
2O3 quartz
3.7
muscovite,
lepidolite
FeO
0.27
0.20
0.35 topaz, apatite0.681
CaO
0.011
minor
zircon, sphene,
magnetite,
0.038
0.021
Na
2O
K2O ilmenite and pyrite
0.018
0.009
2O5
ThisPmaterial
has been0.023
produced in0.005
units of
0.84
0.03 for
100CO
g packaged
in a polyethylene
bottle
2
0.58
0.24
H2O- to users.
delivery
32
24
9
31
9
24
23
10
12
Tables 1 and 2 state the determined
composition of ML-OShBO and the
associated expanded uncertainties. A full
page 1 of 5
description of how these values and their
uncertainties have been established can be
found in Kane et al. (2003). Table 3 provides
additional information that is essential for
user laboratories to evaluate their own
results for the CRM in the manner outlined
in ISO Guide 33 (ISO 2000).
Intended uses of this CRM:
This CRM is intended for use in calibration
and quality control by laboratories when
analyzing samples that are matrix-matched
to ML-OShBO.
IAG CRM-3 Alkaline Granite MGL-OShBO
Table 1. Certified Values
and their Uncertainties;
Mass fraction or concentration
Oxide/Element
SiO2
Al2O3
Fe2O3(TOT)
FeO
MnO
CaO
Na2O
K2O
P2O5
H2OF
LOI
Ce
Cu
La
Li
Lu
Nb
Nd
Ni
Pb
Rb
Sc
Sm
Sr
Ta
Th
Yb
Zn
Zr
CV
±U
in % m/m
71.72
0.29
16.12
0.12
0.500
0.029
0.299
0.004
0.149
0.017
0.388
0.011
5.34
0.26
3.58
0.04
0.0293
0.0017
0.074
0.020
1.13
0.16
1.10
0.04
in mg/kg
27.4
1.6
7.1
1.1
8.4
0.7
1730
40
0.326
0.021
64
4
15.5
0.5
10.7
1.6
63
6
2360
110
9.2
1.4
6.0
0.4
12.3
1.1
46.7
2.4
13.3
0.8
2.38
0.13
92
6
40.1
2.8
N
48
40
23
11
40
31
34
32
11
15
10
23
12
16
12
15
10
19
10
17
18
29
11
10
17
12
10
10
25
16
page 1 of 6
demand for high-quality reference materials. As a result of this latest
certification round, and in conjunction with the increased personnel
resources of our certification committee, the IAG has now established
a structure for the routine production of new Certified Reference
Materials. The ultimate goal of our efforts is the production of one or
two carefully selected CRMs over a given 18-month interval.
Establishment of a Geochronology Special Interest Group
At its March 2009 meeting in London, the IAG Governing Council
approved the establishment of a new geochronology special interest
group. Though intended to support the needs of analysts active in the
field of isotopic dating, this interest group will initially tackle key
metrology issues affecting the U–Pb dating method. Recommendations
for standardizing data reduction protocols and the organization and
evaluation of round robin analyses are two possible areas of early
activity. Details about this new IAG undertaking will be reported in
forthcoming issues of Elements.
Best regards from Potsdam,
IAG Releases Two New Certificates of Analysis
In March 2009 the IAG completed work on its latest round of ISOcompliant sample certifications. Two new Certificates of Analysis have
now been released, representing the second and third whole rock powders to have achieved the highest metrological status. Both MGL-GAS
(serpentinite) and MGL-OShBO (alkaline granite), with 11 and 28 certified element concentrations, respectively, are now available for purchase from our partner organization, the Central Geological Laboratory
(www.cengeolab.com). This certification round, led by Jean Kane, who
stepped down as chairperson of the IAG’s sample certification committee in 2007, demonstrates the IAG’s ability to respond to the growing
E lements
Table 1. Certified Values
International
Association of Geoanalysts’
and their Uncertainties;
181
Michael Wiedenbeck
President, International Association of Geoanalysts
([email protected])
J une 2009
Mineralogical Society of Great Britain and Ireland
www.minersoc.org
From the Executive Director
The early part of the year is always a good time. Members interact with
the Society around now to pay their membership fees, to order publications,
to apply for bursaries, and to make nominations for Society awards.
My office is 50 km from the nearest geologist and in a separate country
from where the main office is, so communication with members, for the
reasons above, or in relation to a paper in a journal, registration for a
conference, etc., is always welcome and enjoyable.
This year we are delighted that we have had so many new student members.
Students are attracted by Elements and other benefits of membership,
including bursaries and cheaper registration fees for conferences.
Student Bursaries and Senior Bursary
Between the central Society bursary fund and monies offered by the
special interest groups, up to £10,000 per year are paid out in grants.
The money can be used to support academic work by allowing attendance at overseas conferences and meetings, encouraging international
collaboration involving research of high merit, or supporting fieldwork.
At the March 2009 meeting of Council, the following student bursaries
were agreed: E. Badenszki, to carry out MCLA-ICP-MS work at Keyworth,
Nottingham, UK; A. Baxter and P. Bots, to attend the Goldschmidt
Conference in Davos, Switzerland; C. Breheny, to carry out analytical
work at Camborne School of Mines, University of Exeter, UK; J. Darling,
to attend the AGU joint assembly in Toronto, Canada; L. Duthie and
S. Lawther, to attend the EGU conference in Vienna; N. Lloyd, to attend
the Asia Pacific Symposium on Radiochemistry in California, USA; I.
Neill, to attend the Fall AGU meeting in San Fransisco, USA; A. McAnena,
to visit the Stable Isotope Laboratory at the University of Maryland,
USA; A. D. Sumoondur, to carry out low-T Mossbaüer spectroscopy at
the University of Copenhagen, Denmark; A. Valdes-Duran, to attend
the William Smith Meeting of the Geological Society of London, UK;
and V. Vry, to carry out laboratory work at the University of Tasmania.
Paul Nadeau (right), receiving the George Brown lecture certificate from Steve Hillier,
chairman of the Clay Minerals Group
Understanding the impacts of these processes on permeability evolution,
porosity loss, overpressure development, and fluid migration in the subsurface has led to the realization that exploration and production risks are
exponential functions of temperature. Global compilations of oil/gas
reserves relative to reservoir temperature have confirmed the ‘Golden Zone’
theory, and have stimulated further research to determine in greater detail
the geological/mineralogical controls on hydrocarbon migration and
entrapment efficiency within the Earth’s sedimentary basins.
The Senior Bursary this year is divided amongst the following: R. Cooke,
for a research visit to the University of Salzburg; A. Costanzo, to attend
the Goldschmidt Conference in Davos, Switzerland; B. O’Driscoll, to carry
out field work on the Shetland Isles, Scotland; H. Rollinson, to attend
an international discussion meeting on continental geology and tectonics
at Northwest University, China; and C. Storey, to carry out collaborative
research with colleagues at the University of Stellenbosch, South Africa.
The next deadline for application for Society bursaries is 15 January 2010.
However, some of the Society’s special interest groups might be able to
help with small amounts of money to help with travel costs for a meeting,
etc., in the meantime. Please see the SIG web pages at www.minersoc.org.
The George Brown Lecture
The 9th George Brown Lecture of the Clay Minerals Group was delivered
at the Macaulay Institute on 11 March 2009 by Dr Paul Nadeau of Statoil
Hydro. His lecture “Earth’s Energy ‘Golden Zone’: A Triumph of
Mineralogical Research“ will be published in paper form in a forthcoming issue of Clay Minerals. A summary follows.
The impact of diagenetic processes on petroleum entrapment and
recovery efficiency has focused the vast majority of the world‘s oil and gas
reserves into relatively narrow thermal intervals, which we call Earth’s
energy ‘Golden Zone’. Two key mineralogical research breakthroughs
underpinned this discovery. The first is the fundamental particle theory of
clay mineralogy, which showed the importance of dissolution/precipitation
mechanisms in the formation of diagenetic illitic clays with increasing depth
and temperature. The second is the surface area precipitation rate models
for the formation of diagenetic cements, primarily silica, in reservoirs.
E lements
182
Kevin Murphy ([email protected])
Mineralogical Magazine
Under the excellent stewardship of Dr Mark Welch, Mineralogical
Magazine is thriving. We are slowly catching up on the delay in
publication, and manuscript turnaround is now as little as eight
weeks from submission to publication online. Full-colour publication is available free of charge, and authors are given a free
e-print at the time of online publication. Each issue now contains
a top-rank review, including papers arising from Hallimond
Lectures and, in some cases, from Society medallists.
Some long-standing members of the journal’s Editorial Board have
decided to stand down, and we are extremely grateful to them for
their service: A. Brearley, M. Holness and P. W. Scott. The Editorial
Board is currently as follows:
F. CÁMARA
G. CAWTHORN
A. G. CHRISTY
B. A. GEIGER
E. S. GREW
G. D. GATTA
C. HAYWARD
K. HUDSON-EDWARDS
S. KRIVOVICHEV
C. A. POLYA
A. PRING
T. R. RILEY
E. SOKOLOVA
C. STOREY
E. VALSAMI-JONES
C.N.R., Italy
University of the Witwatersrand, South Africa
Australian National University, Canberra, Australia
University of Kiel, Germany
University of Maine, USA
University of Milan, Italy
University of Edinburgh, UK
Birkbeck College, London, UK
St. Petersburg State University, Russia
University of Manchester, UK
South Australia Museum, Adelaide, Australia
British Antarctic Survey, Cambridge, UK
University of Manitoba, Winnipeg, Canada
University of Portsmouth, UK
Natural History Museum, London, UK
It is largely on account of this group and the large band of reviewers,
often times the unsung heroes of journal publishing, that we have
such quick turnaround times. Feel free to speak with any of the
Editorial Board members. They will be glad to help with enquiries
about publishing in MinMag.
J une 2009
MicroAnalysis Processes, Time
INTERNATIONAL
TABLES ONLINE
The early-registration deadline for
the Society’s 2009 annual meeting,
MicroAnalysis Processes, Time, is 8 July.
Please do consider registering and submitting an abstract at www.minersoc.org/
pages/meetings/MAPT/MAPT.html
At the time of writing the following sessions, convenors and invited speakers
have been confirmed:
1 A
dvances in the application of
accessory mineral analysis to
understanding crustal processes
2
Decoding polymetamorphism
in mountain belts: from P-T-t-d
records to geodynamic models
– Keynote: Romain Brouquet
(Potsdam)
Tom Argles (Open University)
Clare Warren (Open University)
Mark Caddick (ETH Zurich)
3
Deep subduction and
exhumation of continental
and oceanic crust
Cees Jan de Hoog (University of Oxford)
Simon Cuthbert (University of West of Scotland)
Gaston Godard (University of Paris 7)
Paddy O’Brien (Potsdam)
4 Mantle processes: insights from
peridotite massifs, xenoliths,
xenocrysts and diamonds –
Keynotes: Frank Brenkner, Ofra
Klein Ben David
5 Deep Earth mineral physics and
experimental petrology I:
probing geochemical and
physical processes (recent
developments from nano-beam
and in situ techniques)
6 Deep Earth mineral physics and
experimental petrology II: the
fate of subducted material from
lithosphere to core
7 Pushing the limits of highprecision radioisotope
geochronology: techniques,
tools and applications
8 LA-ICPMS isotopic and trace
element analysis: techniques and
applications to solid Earth studies
– Keynote: Takafumi Hiirata
Gilles Chazot (University of Brest)
Graham Pearson (University of Durham)
Thomas Stachel (University of Alberta)
Anne-Line Auxende (University of Paris 7),
Chrystèle Sanloup (Universities of Paris 6 and
Edinburgh)
David Dobson (University College London)
Falko Langenhorst (Universität Bayreuth)
• 6000 pages
• 300 chapters
Falko Langenhorst (Universität Bayreuth)
Anne-Line Auxende (University of Paris 7)
Chrystèle Sanloup (Universities of Paris 6 and
Edinburgh)
David Dobson (University College London)
• 680 tables of
fundamental data
Dan Condon (British Geological Survey)
Blair Schoene (University of Geneva)
Simon Kelley (Open University)
• 1100 tables of
symmetry
information
Craig Storey (University of Bristol)
Matt Horstwood (British Geological Survey)
Franck Poitrasson (LMTG Toulouse)
9 Light element isotopes: analysis
and applications to mass fluxes
in the Earth
Simone Kasemann (University of Edinburgh)
Tim Elliott (University of Bristol)
10 Fingerprinting exhumation:
advances in thermochronology
and sediment provenance analysis
Fin Stuart (SUERC, UK)
Cornelia Spiegel (University of Bremen)
11 Recent advances in metamorphic and igneous petrology
Horst Marschall (University of Bristol)
Mark Jessell (LMTG Toulouse)
12 The role of microanalysis and
microtextures in under-standing
magmatic processes
Jon Davidson (University of Durham)
Marian Holness (University of Cambridge)
Dan Morgan (University of Leeds)
13 Electron microscopy,
microstructural analysis and grain
scale processes: insights and
frontiers – Keynotes: Dave Prior;
Carol Trager-Cowan; Rainer Abart
14 New advances in transmission
electron microscopy
characterisation and preparation
of minerals
The definitive resource
and reference work for
crystallography and
structural science
Simon Harley (University of Edinburgh)
Jean-Marc Montel (LMTG Toulouse and
CRNS Nancy)
Lutz Nasdala (University of Vienna)
• interactive
features and
resources
Kate Brodie (University of Manchester)
Alan Boyle (University of Liverpool)
Florian Heidelbach (Universität Bayreuth)
David Mainprice (University of Montpellier 2)
Patrick Cordier (University of Lille 1)
Falko Langenhorst (Universität Bayreuth
Michael Carpenter (University of Cambridge)
15 Mineral microstructures: their
implications and applications
– Keynote: Andrew Walker
Ian Parsons (University of Edinburgh)
Alain Baronnet (Paul Cézanne University and
Centre Interdisciplinaire de Nanoscience de
Marseille)
Rainer Abart (Freie Universität Berlin
16 New advances in mineral
deposit geology – Keynotes:
Marcel Guilong; David Selby
Martin Smith (University of Brighton)
Gawen Jenkin (University of Leicester)
17 Mineralogy of nuclear wastes –
Keynote: B. Grambow
Fergus Gibb (University of Sheffield)
Ian Farnan (University of Cambridge)
E lements
it.iucr.org
183
J une 2009
Geochemical Society
www.geochemsoc.org
Call for 2010 Award Nominations
Goldschmidt 2009 Bloggers
This year in Davos, you may notice a slight increase in
the frequency of attendees pecking away at their laptops during talks. At first glance it may seem that they
have given up on the current speaker in favor of
checking their e-mails or putting in last-minute changes
to their own slides, but reality is quite the opposite.
This year, some attendees will be taking very detailed
notes about some talks because, in addition to all of the normal expectations and stress of attending our annual meeting, they will be contributing to the Geochemical Society’s first-ever Goldschmidt Conference
blog.
Before getting into the details of what this means, it must be acknowledged that a lot of us still don’t quite know what to think of the word
“blog” (a contraction of the term “web-log”). This is completely understandable considering “blogging” is most often associated with technologyenabled teenagers, celebrity gossip, or political punditry. But over the past
few years, blogs have also become powerful scientific communication tools.
There is no standard template for a science blog. For his blog entitled
The Green Grok, Bill Chamaeides (Dean of the Nicholas School of the
Environment at Duke University and Goldschmidt 2009’s “The Earth’s
Future” panel member) draws on years of experience to openly discuss
issues related to sustainability, climate change, and the environment1.
On the other hand, many science blogs are run by science writers/
journalists (they write your press releases, popular science articles,
books, etc.) as additional outlets for writing about exciting research.
From skeptic to student, science bloggers work collectively towards an
important goal: increasing the public dialogue about science.
Once again it is time to ask for nominations for the Goldschmidt Medal,
Clarke Medal, Patterson Medal, Treibs Medal, and GS/EAG Geochemical
Fellow Awards. October 31, 2009, is the deadline for nominations to
be considered for these awards. For information on nomination requirements, visit the Geochemical Society website at www.geochemsoc.org/
awards. Please take the time to highlight the accomplishments of your
valued friends and colleagues by nominating them. With your help,
we can ensure that all of geochemistry is recognized and all deserving
geochemists are considered.
• The V.M. Goldschmidt
Medal is awarded for major
achievements in geochemistry or
cosmochemistry, consisting of
either a single outstanding contribution or a series of publications that have had great influence on the field.
• The F.W. Clarke Medal is
awarded to an early-career scientist
for a single outstanding contribution to geochemistry or cosmochemistry, published either as
a single paper or a series of
papers on a single topic.
• The GS/EAG Geochemistry
Fellow Award is bestowed
upon outstanding scientists who
have, over some years, made a
major contribution to the field
of geochemistry.
The Nominations Committee of the Geochemical Society is seeking
nominees for vice-president and for three seats on the Board of
Directors for terms beginning in 2010. The new vice-president will
become president in 2012. The new board members will replace
retiring directors Yaoling Niu, Seth (Swami) Krishnaswami, and
Marilyn Fogel. One of these directors must reside outside of North
America. Board members should be outstanding geochemists with
a keen interest in the work of the Society and be willing to travel
to the annual board meeting at the Goldschmidt Conference. The
nominees for vice-president should have established reputations
of leadership in geochemistry and be willing to devote considerable time and effort to the work of the Society.
Another objective of the blog will be to increase the visibility of the
Society and attract new members. In the last issue of Elements (April
2009, p. 124), Martin Goldhaber mentioned some recent efforts to increase
membership, especially among young researchers more likely to follow
blogs and other web-based communication methods.
Suggestions may be communicated by July 31, 2009, to any
member of the 2010 Nominations Committee or to the GS business
office. More information regarding the duties and responsibilities
of board positions can be found on the Geochemical Society website.
So this year at Goldschmidt, try not to instinctively sneer at graduate
students typing on their laptop in the back of the room during a talk.
Instead, find them during a break and tell them you appreciate their
efforts. And while you’re at it, maybe you should buy them a beer too
(you’re welcome, students). Finding time to write among other conference
duties is not an easy task, but when the reason is to help communicate
what we do at Goldschmidt and why it’s important, I think we all can
agree it’s well worth the effort.
Geochemical Society Business Office
Seth Davis, Business Manager
Kathryn Hall, Administrative Assistant
Washington University in St. Louis
Earth and Planetary Sciences, CB 1169
One Brookings Drive, Saint Louis, MO 63130-4899, USA
E-mail: [email protected]
Phone: 314-935-4131 – Fax: 314-935-4121
Website: www.geochemsoc.org
Please follow the progress of our conference blog at
http://geochemicalnews.wordpress.com/.
Nicholas Wigginton2
1 The Green Grok: www.nicholas.duke.edu/thegreengrok
E lements
• The Alfred Treibs Medal
is awarded by the Organic
Geochemistry Division for major
achievements, over a period of
years, in organic geochemistry.
Call for Nominations for Officers
and Directors
Our “live” conference blog will be written by not one, but a number
of attendees with broad backgrounds and expertise—from graduate
students to Geochemical Society President Martin Goldhaber. The blog
will cover talks from a wide sampling of scientific themes, as well as
events like field trips, poster sessions, award ceremonies, and pretty
much anything related to Goldschmidt 2009. In the absence of webcasting from the conference (see Martin Goldhaber’s letter on p. 48 of
the February 2009 issue of Elements), the blog will be a less technically
and financially challenging means for non-attending GS members to
follow the week’s events. Conference attendees might also find it useful
to track the blog live from Davos.
2 Nicholas Wigginton is the former editor of Geochemical News. He is currently an
associate editor of Science and can be reached by e-mail at [email protected]
• The C.C. Patterson Medal is
awarded for a recent innovative
breakthrough in environmental
geochemistry of fundamental
significance, published in a
peer-reviewed journal.
Read also Peter Deines’ obituary on page 144.
184
J une 2009
The Clay Minerals Society
www.clays.org
Contents of the April 2009 issue
of Clays and Clay Minerals
The President’s Corner
The year has flown by. Since the high-office term of
the CMS ranges from June to June, I am crafting my
last set of words for Elements. The CMS topics that
have come forward this year have been diverse:
Texas state law as it affects the science text portrayal
of evolution, print journals in a rapidly evolving
electronic world, the ability of geoscience organizations to recruit youthful members, and the economic
condition of the globe. These issues allow me to
understand how important the CMS is in the broader
scale of geoscience study and the global perspective.
Andrew Thomas,
outgoing CMS
president, somewhere
in the Rotliegend
The CMS seeks individuals with youthful attitudes
toward clay science and volunteerism. Derek Bain,
your incoming president, may call upon you to lend him a hand. Agreeing
to help would not only be beneficial to him, but it would be vital to
maintaining and growing the society that we know as the CMS.
The CMS has a new website, for those who haven’t yet seen it. This
website, created through the tireless efforts of Ray Ferrell, gets us a bit
closer to the look and feel that we desire. Hopefully the site also gets
you a bit closer to the CMS data that you need and makes them a bit
quicker to access. A special thanks to Ray for seeing this project through.
It has been my pleasure to work for the Society this year. I have been
fortunate to have thoughtful and dedicated colleagues and committee
members. I look forward to doing more for the Society one day, maybe after
having had a chance to recharge my batteries. There is much yet to do.
The Clay Minerals Society, chartered in 1963, is the largest clay mineral
society in the world. Its diverse membership, which bridges industry,
academia, and government, meets once a year. We invite you to join
us in future meetings, and particulars regarding dates and content can
be found at https://cms.clays.org/meetings/. Our next annual meeting
will be in Spain, June 6–11, 2010, and will be held in conjunction with
the Spanish and Japanese Clay Groups. See you there!
Respectfully,
Andrew Thomas
President, The Clay Minerals Society
Chevron Energy Technology Company, Houston, Texas, USA
[email protected]
H åkon Fischer, P eter G. Weidler,
Bernard Grobéty, Jörg Luster, and
A ndreas U. Gehring. The transformation of synthetic hectorite in
the presence of Cu(II)
Shoji Morodome and K atuyuki
K awamura. Swelling behavior of
Na- and Ca-montmorillonite up
to 150°C by in situ X-ray diffraction
experiments
Motoharu K awano, Tamao H atta,
and Jinyoen Hwang. Enhancement
of dissolution rates of amorphous
silica by interaction with amino
acids in solution at pH4
Tomáš Grygar, Jaroslav K adlec,
A nna Ž igová, M artin Mihaljevi č,
Tereza Nekutová, R ichard L ojka,
and Ivo Sv ětlík .
Chemostratigraphic correlation
of sediments containing expandable clay minerals based on ion
exchange with Cu(II) complex
with triethylenetetramine
Giovanni Valdré, Daniele
M alferrari, and M aria Franca
Brigatti. Crystallographic features
and cleavage nanomorphology of
clinochlore: specific applications
Z haohui Li and Wei-Teh Jiang.
Interlayer conformations of
intercalated dodecyltrimethylammonium in rectorite as determined by FTIR, XRD, and TG
analyses
Bingsong Yu, H ailiang Dong,
Hongchen Jiang, Guo Lv, Dennis
Eberl, Shanyun Li, and Jinwook Kim.
The role of clay minerals in
preservation of organic matter in
sediments of Qinghai Lake, NW
China
Bryan R. Bzdek and Molly M.
McGuire . Polarized ATR-FTIR
investigation of Fe reduction in
the Uley nontronites
Navdeep K aur, M arkus Gräfe,
Balwant Singh, and Brendan
K ennedy. Simultaneous incorporations of Cr, Zn, Cd and Pb in
the goethite structure
A niruddha Sengupta. Anisotropy
of magnetic susceptibility study
of kaolinitic clay matrix subjected
to biaxial tests
A bdelaziz Benhammou, Boumediene
Tanouti, L ahbib Nibou, A bdelrani
Yaacoubi, and Jean-Paul Bonnet.
Mineralogical and physico-chemical investigation of Mg-smectite
from Jebel Ghassoul, Morocco
Journal
Under the guidance
of Editor-in-Chief Joe
Stucki, Clays and Clay
Minerals is undergoing
a facelift and will soon
take on a new look.
Here is a preview.
The All-New CMS Website
Bookmark it, use it, and let us know how to improve it!
E lements
A lexandra A limova, A. K atz,
Nicholas Steiner, Elizabeth
Rudolph, Hui Wei, Jeffrey C.
Steiner, and Paul Gottlieb.
Bacteria-clay interaction: structural
changes in smectite induced
during biofilm formation
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Mineralogical Society of America
www.minsocam.org
From the President
A Mineral by Any Other Name…?
Minerals have been given names since the beginning of recorded history. It was not until 1959,
when the International Mineralogical Association
(IMA) established the Commission on New Minerals
and Mineral Names, that an effort was made to
regulate the nomenclature of minerals on an international level. In 2006, IMA formed the Commission
on New Minerals, Nomenclature and Classification
(CNMNC) by merging the existing Commission
on New Minerals and Mineral Names and the
Commission on Classification of Minerals (see
Elements, volume 2, 2006, page 388). The CNMNC is now in charge of
controlling the introduction of new minerals and mineral names, as
well as reviewing existing systems of mineral classification.
Because of these concerns, MSA urged IMA leadership not to change
existing mineral names unless there were scientifically compelling reasons to do so. Changing a mineral name simply to clarify its composition
or polysomatic character is not viewed as a compelling reason. In addition,
it was recommended that the CNMNC consider implementing a procedure
whereby proposed changes in accepted mineral names are publicly
announced and a mechanism for public commentary and participation
is provided. This would help ensure that the CNMNC represents the
needs and the expertise of the community of professional mineralogists.
MSA respects the enormous contribution that the CNMNC has made
to the science of mineralogy since the Commission’s inception. Dr. Peter
Williams has indicated that the Commission is aware of the concerns
expressed by the community, as is Dr. Tony Kampf, MSA’s representative
on the CNMNC. We are encouraged by these responses and hope that
MSA will continue to be guided by and honor the decisions that the
Commission renders on matters of mineral nomenclature.
MSA has long recognized the vital role that members of the commission have made to validate new minerals. The American Mineralogist
strives to follow the recommendations of the CNMNC, as do all the
major professional mineralogical journals. However, if you subscribe
to the MSA-listserv, you will be aware of a vigorous e-mail exchange
in the past year regarding decisions rendered by the CNMNC that
change the names of previously approved and valid mineral species.
In particular, deep concern has been expressed about the CNMNC’s
decision to rename minerals whose names have deep historical roots
and enjoy widespread usage across the spectrum of physical, chemical,
and biological sciences. I thought it important to report on what
resulted from these concerns expressed by our members.
At its 2008 fall meeting, MSA Council reviewed and approved a letter
that was composed by Past President Peter Heaney and subsequently
sent to Professor Takamitsu Yamanaka, president of the IMA, with a copy
to Dr. Peter Williams who is the new chair of the CNMNC. The letter
outlined many of the concerns expressed by MSA members, namely:
Nancy Ross
MSA President ([email protected])
Notes from Chantilly
• Balloting for the 2009 election of MSA officers and councilors
is underway. The candidates are: for president, John B. Brady; for
vice president, David L. Bish and David M. Jenkins; for secretary,
Mickey Gunter; for councilor (two to be selected), Wendy A. Bohrson,
Sumit Chakraborty, Abby Kavner, and Mark David Welch. Darrell
Henry continues in office as treasurer. Continuing councilors are Peter
C. Burns, Carol D. Frost, Penelope L. King, and Marc M. Hirschmann.
MSA members should have received voting instructions at their
current e-mail addresses. Those who do not wish to vote online
can request a paper ballot from the MSA business office. As always,
the voting deadline is August 1.
• In the judgment of many scientists, the changes that the CNMNC
have proposed are more confusing than the status quo, thus defeating
the presumed rational for renaming.
• The MSA had a booth at the Tucson Gem and Mineral Show,
Tucson, Arizona, USA, 12–15 February 2009. The Dana Medal will
be presented to Ronald E. Cohen at the Goldschmidt 2009 meeting,
Davos, Switzerland, 21–26 June 2008. MSA will have a booth at
the GSA meeting, in Portland, Oregon, USA, 18–21 October 2009.
During that week MSA will also hold its Awards Lunch, the MSA
Presidential Address, a joint MSA–GS reception, its annual business
meeting, a Council meeting, and breakfasts for the past presidents
and associate editors. Do not forget the lectures by the Roebling
Medalist, Alexandra Navrotsky, and the MSA Awardee, Thomas
Patrick Trainor. More information is available on the MSA website.
• When the CNMNC overrules its own recent verdicts, it sends mixed
and conflicting signals to the mineralogical community. For example,
the CNMNC reaffirmed the validity of hydroxylapatite and fluorapatite
as recently as 1998 in an official IMA publication authored by Nickels
and Grice. Now the names are to be changed.
• All 2007 and 2008 MSA members have been contacted by mail,
electronically, or both about renewing their membership for 2009.
If you have not renewed your MSA membership, please do so. If
you have not received a notice by the time you read this, please contact
the MSA business office. You can also renew online at anytime.
• Mineral names embody the rich history of man’s exploration of the
Earth, and the elimination of longstanding usages erases an important
part of our scientific experience.
• If you have not been getting the few e-mail announcements from
MSA about new issues of the American Mineralogist online, voting,
your renewal, or confirmation of your online orders, either we do
not have a working e-mail address for you or your system is
blocking messages from MSA. Consider rectifying the situation.
Otherwise, you will need to keep watch on this column or the
MSA website for news about these matters.
• Certain mineral names are so deeply ingrained in the literature that
efforts to change them will be fruitless. The use of chemical prefixes
for minerals such as fluorapatite and manganotantalite is over a century
old. When the CNMNC issues decisions that are unlikely to be followed
and are inherently unenforceable, it undermines its authority.
J. Alex Speer
MSA Executive Director
[email protected]
E lements
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Other Publications Available from MSA
Diamonds of Siberia:
Photographic Evidence for Their Origin
By Z.V. Spetsius and L.A. Taylor,
and published by Tranquility Base Press
378 pp., hardbound
ISBN 978-0-9795835-0-6
Mineralogy
and Optical Mineralogy
• US$62 (members)
• US$92 (nonmembers)
by Darby Dyar and Mickey Gunter
Illustrated by Dennis Tasa
Handbook of
Mineralogy
• A textbook designed for
college-level courses in rocks
and minerals, mineralogy, and
optical mineralogy
• Covers crystallography, crystal chemistry, systematic
mineralogy, and optical mineralogy
• Organized to facilitate spiral learning of increasingly
complex material
• DVD-ROM (included) with well over a thousand
animations plus full-color images of all figures in text
• Printable, searchable mineral database on DVD-ROM
to allow customized creation of lab manuals
• DVD-ROM has demo versions of CrystalMaker software
to view mineral structures and simulate their power and
single crystal diffraction patterns.
• Ordering info, book and DVD-ROM content at
www.minsocam.org/MSA/DGTtxt
• Non-member price: $90, member price: $67.50
ISBN 978-0-939950-81-2
Five-volume set authored
by John W. Anthony,
Richard A. Bideaux,
Kenneth W. Bladh, and
Monte C. Nichols, and
published by Mineral
Data Publishing
Volumes I to V complete set
• US$441 (members)
• US$588 (non-members)
STILL AVAILABLE AS INDIVIDUAL VOLUMES: Vol. I, Elements,
Sulfides, Sulfosalts, $100; Vol. III, Halides, Hydroxides, Oxides,
$108; Vol. IV, Arsenates, Phosphates, Vanadates, $130; Vol. V
Borates, Carbonates, Sulfates, $130
Shipping additional. For description and table of contents of these
books and online ordering, visit www.minsocam.org or contact
Mineralogical Society of America, 3635 Concorde Pkwy Ste 500,
Chantilly, VA 20151-1110, USA. Phone: +1 (703) 9950;
fax: +1 (703) 652-9951; e-mail: [email protected]
American Mineralogist
Editors: Dana Griffen, Jennifer Thomson, and Bryan Chakoumakos
We invite you to submit for publication the results of
original scientific research in the general fields of mineralogy,
crystallography, geochemistry, and petrology. Specific areas of
coverage include, but are not restricted to, igneous and metamorphic petrology, experimental mineralogy and petrology,
crystal chemistry and crystal-structure determinations, mineral
spectroscopy, mineral physics, isotope mineralogy, planetary
materials, clay minerals, mineral surfaces, environmental
mineralogy, biomineralization, descriptive mineralogy and new
mineral descriptions, mineral occurrences and deposits, petrography and petrogenesis, and novel applications of mineralogical
apparatus and technique. Submit regular papers of any length
and timely, size-limited Letters at http://minsocam.allentrack.
net; contact editors first about Review papers.
In Memoriam
Joseph P. Orosz (Member – 2005)
Willis D. R ichey (Member – 1985)
Detailed information on manuscript preparation available at
http://www.minsocam.org/MSA/AmMin/Instructions.html
Quick Facts
• Average of recent 266 papers—submission-toacceptance time:
140 days (~4.6 months) (s.d. 100 days)
• Average of recent 166 papers—submission-topublication:
308 days (~10 months) (s.d. 104 days)
• See our list of most-read and most-cited papers
via GSW: http://ammin.geoscienceworld.org/
American Mineralogist
Founded in 1916
E lements
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Mineralogical Association of Canada
www.mineralogicalassociation.ca
2009 Award Winners
The Mineralogical Association of Canada (MAC) presented its 2009
awards at its annual luncheon on May 26, 2009, during the Meeting of
the Americas conference in Toronto.
Martin A. Peacock Medal to Don Francis
The Peacock Medal, formerly
the Past Presidents’ Medal, is
the highest honor bestowed
by MAC. This year, it was
awarded to Don Francis of
McGill University, Montreal,
Canada, for his contributions to the elucidation of
the composition of Earth’s
upper mantle and for his
unique ability to integrate
fieldwork with mineralogy
and geochemistry to solve
significant problems in petrology. Don’s research in petrology has not
only impacted our thinking on mantle processes, but it has also greatly
enhanced our understanding of tectonics. In particular, his novel study
of mantle xenoliths in the Canadian Cordillera has shown that the
character of xenoliths changes across major fault boundaries in the
Cordillera, suggesting that the faults are deeply rooted and that terranes
in the Cordillera come complete with their lithospheric mantle.
Don Francis was born in Montreal and grew up in the West Island
where, as a boy scout, he developed a passion for the Canadian North
reading tales of the early explorers. He completed an Honors BSc in
geological sciences at McGill University in 1968, an MSc with Hugh
Green at the University of British Columbia in 1971, followed by a PhD
with Tom McGetchin at MIT. Don returned to McGill as a professor in
1974 and has remained there ever since. Don’s research uses chemistry
to investigate the origin of mafic magmas in the Earth’s mantle. He
and his students have studied magmatic suites spanning the history of
the Earth in field-based projects in northern Quebec, Baffin Island, the
NWT, northern British Columbia, and the Yukon.
Hawley Medal to Anderson, Wirth, and Thomas for the best
paper published in The Canadian Mineralogist in 2008
Anderson AJ, Wirth R, Thomas R (2008) The alteration of metamict zircon
and its role in the remobilization of high-field-strength elements in the
Georgeville granite, Nova Scotia. Canadian Mineralogist 46: 1-18
This paper was unanimously selected by the Hawley Medal selection
committee for its depth of understanding of the structure and composition of metamict zircon from the Georgeville epizonal A-type granite
from the Antigonish Highlands, Nova Scotia. The paper integrates data
from EMPA, SXRF, LA–ICP–MS, Raman microspectroscopy, and TEM
to provide exceptional new insights into the open-system behavior of
alpha-decay-damaged zircon in the presence of subsolidus fluids. For
the first time, detailed micro- and nanoscale element-distribution maps
indicate which elements in metamict zircon can be redistributed during
alteration. This paper questions our assumptions about the chemical
durability of zircon and its suitability for petrogenetic studies, particularly U- and Th-rich zircon from highly evolved granites, aplites, and
pegmatites. It also links the mineral chemistry of zircon with bulk
chemistry of the high-field-strength elements, anomalous Nd isotopic
signatures, and the selective transport and precipitation of the REE
within the Georgeville granite.
E lements
Alan J. Anderson is a professor in the Department
of Earth Sciences at St. Francis Xavier University
in Antigonish, Nova Scotia, where he has been a
faculty member since 1989. He received his BSc
in geology at the University of Windsor, his MSc
at the University of Manitoba, and his PhD at
Queen’s University in Kingston, Ontario. He spent
two years as a postdoctoral fellow at the fluids
research laboratory at Virginia Tech and was a guest
scientist at the German Research Centre for
Geosciences, Potsdam, in 2003. Alan’s research
focuses on the chemical and physical properties of solvothermal fluids
in the Earth’s crust and their role in geochemical processes such as
mass transfer and ore formation.
Richard Wirth is supervisor of the electron
microscopy (FIB/TEM) laboratory at the GFZ
German Research Centre for Geosciences,
Potsdam, Germany. He received his PhD in 1978
at the University Würzburg, Germany. He spent
3 years as a postdoctoral fellow at the Institute
of Metals Physics at the University of Saarbruecken,
followed by research scientist positions at the
University of Cologne, the Institute of Advanced
Materials, Saarbruecken, and Ruhr-UniversityBochum. In 1994 he established the TEM laboratory at the GFZ Potsdam, which he has continued to develop by incorporating modern technologies such as the focused ion beam (FIB).
Rainer Thomas received his master’s degree
in mineralogy, his PhD, and his Habilitation at
Freiberg University of Mining and Technology.
He worked in the semiconductor industry from
1969 to 1988, where he carried out research on
crystal growth by chemical transport reactions,
developed polishing technologies for silicon
wafers, and performed X-ray studies on crystals
using single- and double-crystal topographic
techniques and multiple-diffraction measurements. He began work as a research scientist in
1988 at the Central Institute of Physics of the Earth in Potsdam, and
then joined the GeoForschungsZentrum Potsdam in 1992, where he
remained until his retirement in 2007.
Young Scientist Award to Christopher Herd
The Young Scientist Award is presented to a young
scientist who has made a significant international
research contribution as a promising start to a
scientific career. The winner for 2009 is Chris Herd,
a prolific young scientist who has already greatly
impacted our understanding of how Martian
basalts form and what they record about the red
planet. Chris completed his undergraduate degree
in geological sciences at Queen’s University in
1997. His interest in meteorites from Mars took
him to the University of New Mexico in Albuquerque
for his PhD. In 2001 he moved to the Lunar and
Planetary Institute in Houston, where he worked
as a postdoctoral fellow with access to the facilities at the Johnson
Space Center. He was hired in July 2003 by the Department of Earth
and Atmospheric Sciences at the University of Alberta, where he was
awarded tenure in 2008.
Chris’s early work focused on carefully evaluating the oxidation state
of Martian basalts, and then deciphering the controls on oxidation
state during the petrogenesis of these basalts. He subsequently worked
188
J une 2009
on the partitioning of light lithophile elements in Martian meteorites
to evaluate their behavior and the implications for degassing of magmatic
water and, by inference, water in the Martian mantle. This research has
made him a recognized expert on basalts as probes of planetary interior
redox states.
Chris has also impacted the broader scientific community by cofounding
a new institute at the University of Alberta dedicated to space exploration
and science. By actively promoting the meteorite collection at the
University of Alberta and through dedicated, extensive outreach, Chris
has helped to popularize meteorites and planetary science in Canada.
COUNCILLORS 2009–2012
We welcome Elena Sokolova and Kim Tait as incoming councillors
and thank outgoing councillors Jim Mungall, Paula Piilonen, and
Jim Scoates.
Elena Sokolova is a professor in the
Department of Geological Sciences, University
of Manitoba. She received her BSc, MSc, and PhD
degrees from Moscow State University, Moscow,
Russia, and subsequently worked in the
Department of Crystallography and Crystal
Chemistry. She was awarded a DSc degree
(Doctor of Science) by the same university in
1997. She moved to Canada in 2001. Her research
interests concern primarily the mineralogy
and crystallography of alkaline rocks. In
2004, sokolovaite, a new mica, was named in recognition of her
contribution to mineralogy and crystallography. She is an Academician,
Russian Academy of Natural Sciences, and a Fellow of the
Mineralogical Society of America. She served as an expert in Earth
Sciences (1999–2001) for the Russian Foundation for Basic Research,
as secretary for the All-Russian Mineralogical Society (1995–2001),
and as associate editor of The Canadian Mineralogist (2001–2003).
She is currently an associate editor of Mineralogical Magazine.
Welcoming Andrew Locock as
co-editor of The Canadian Mineralogist
A native of Edmonton, Andrew Locock
obtained both a BSc (Honors in geology)
and an MSc from the University of Alberta.
His MSc thesis focused on the mineralogy
and geochronology of the Ice River alkaline intrusive complex in southeastern
British Columbia. During the course of his
graduate work in Edmonton, he had the
good fortune to assist with the design and
installation of the permanent mineralogy
and geology galleries at what is now the
Royal Alberta Museum. Six years followed
in the fields of diamond exploration and gold exploration in South
America and northern Canada. In 2000, he began his PhD dissertation on the crystal chemistry of uranyl phosphates and uranyl
arsenates under the supervision of Peter C. Burns at the University
of Notre Dame, completing this work in 2004. At present, Andrew
is located at his alma mater in his hometown of Edmonton. He is
eager to be able to assist in the production of The Canadian
Mineralogist and to help maintain its high standards. He started
working with Bob Martin in January 2009.
SECONDARY ION MASS
SPECTROMETRY
IN THE EARTH SCIENCES
Short course volume 41 introduces SIMS analytical techniques and assesses their
applications in the Earth
­sciences. Topics include light
stable and non-traditional
isotope analysis, radiogenic
isotope analysis quaternary
geochronology, and depth
profiling techniques.
Kim Tait received her BSc in 1999 and MSc
in 2002 from the University of Manitoba under
the supervision of Frank Hawthorne and her
PhD from the University of Arizona in 2007
under the supervision of Bob Downs. Her PhD
research was carried out mostly at the Los
Alamos Neutron Scattering Center (LANSCE) in
Los Alamos, New Mexico, USA, where she performed neutron diffraction and inelastic neutron scattering analyses of gas hydrates. She
began work at the Royal Ontario Museum as
associate curator of mineralogy in April 2007 and is head of the
mineralogy section in the Department of Natural History. Kim’s
main interests are new-mineral identification, mineral properties at
extreme conditions (high P, low T), and the high-pressure mineralogy
of meteorites.
ISBN 978-0-921294-50-4
SC 41, 160 pages, 2009
CDN$40 (in Canada)
US$40 (­outside Canada)
(Member Price CDN$32/US$32)
Order your copy at www.mineralogicalassociation.ca
INTERESTED IN GEMS?
We have publications for you!
• SP 10 Pegmatites
– David London (2008)
ISBN 978-0-921294-47-4, 368 pp
• SC 37 Geology of Gem Deposits
– Editor: Lee A. Groat (2007)
ISBN: 978-0-921294-37-5, 288 pages, plus 24 color plates
• SC 40 Laser Ablation ICP–MS in the Earth Sciences
– Editor: Paul Sylvester (2008)
ISBN 978-0-921294-49-8, 348 pages
Order online at www.mineralogicalassociation.ca
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German Mineralogical Society
www.dmg-home.de
Gemstone Short Course and Workshop
Meeting of the Mineral Museums and Collections
Working Group, Freiberg, Germany
The Mineral Museums and Collections Working Group, part of the German
Mineralogical Society (DMG), meets every two years at a German
museum to exchange news and attend two days of talks on a variety
of themes related to mineral museums. This year, 26 members (mostly
curators) met in Freiberg, Saxony, on March 10 and 11.
In addition to the usual program, the group had a unique chance to
attend an in-depth and behind-the-scenes tour through the recently
opened Terra Mineralia museum in the Schloss Freudenstein castle, led
by the conveners of the meeting, Karin Rank and Andreas Massanek.
The exhibit displays minerals of excellent quality, permanently on loan
by Dr. Erika Pohl-Ströher from Switzerland. The castle has been renovated exclusively for this new mineral museum.
Mineral Museums and Collections Working
Group attendees in front of the Mineralogy
Department in Freiberg, Germany.
Photo Renate Schumacher
Schloss Freudenstein, location of
the recently opened Terra Mineralia
museum in Freiberg, Germany.
Photo Renate Schumacher
Gerhard Heide, head of the Mineralogy Department, gave us a warm
welcome and an account of the impact on local geoscience by the
establishment of the new Terra Mineralia museum. Jochen Schlüter,
spokesman for the working group, gave the introductory remarks. Anja
Sagawe from Dresden showed a movie on the application for the M&M7
meeting to take place in Germany in 2012 (see article by Pete Modreski
in Elements, December 2008, p. 426). Further talks on both days of the
meeting addressed topics related to public relations, teaching and special
exhibits (Udo Neumann, Tübingen; Melanie Kaliwoda, Munich; Eckhard
Mönnig, Coburg; Renate Schumacher, Bonn); web-related activities
concerning the catalogue of German type minerals (Jochen Schlüter,
Hamburg); museum and collections management as well as “survival work”
(Birgit Kreher-Hartmann, Jena; Susanne Herting-Aghte, Berlin; Gisela
Lentz, Lütjenburg; Angela Ehling, Berlin); and research activities
(Rupert Hochleitner, Munich; Jochen Schlüter, Hamburg). During break,
attendees had a chance to examine the systematic collections exhibited
in the Freiberg Department of Mineralogy. We also received wonderful
support from the technical staff and were even served home-baked cakes.
A five-day short course and workshop entitled “Non-Destructive Analysis
of Gemstones and Other Geo-Materials” was held on March 2–6, 2009,
at the Institute of Mineralogy and Crystallography, University of Vienna,
Austria. The event was held as a teaching activity in the framework of
the Marie Curie Chair of Excellence for Mineral Spectroscopy and was
organized by the chair-holder, Prof. Lutz Nasdala. The workshop brought
together 44 experts, professionals and students to review the applications,
current state, progress and challenges in the field of gemstone analysis.
Participants came from 12 European countries, Russia, the United States
and Thailand.
Gemstones may undergo various manipulations to enhance their perceived quality. As technology advances, confirming the authenticity of
gemstones becomes more and more difficult, creating a large demand
for non-destructive, time-efficient methods for determining the composition of gemstones and precious metals. Gemstones are geo-materials
whose analysis is not always straightforward. First, the analytical tasks
reach far beyond simple phase identification; they include problems such
as distinguishing between natural and synthetic materials and unravelling different sorts of treatment/enhancement. Second, analyses need
to be done non-destructively, and typical preparation procedures cannot
be applied in most cases.
Key techniques involve X-ray analysis (single-crystal and powder analysis
of unprepared samples) and spectroscopic methods with a main focus on
Raman and luminescence, and also IR and optical absorption spectroscopy.
The short course included both a theoretical basis and practical training
in these analytical methods through a series of ‘hands-on’, expert-led,
interactive teaching sessions (use of analytical systems, data reduction and
interpretation of results), followed by group discussions on instrumentation and tools, development of protocols and technique capability.
Participants were also given the opportunity to analyse their own samples.
Participants on the roof of the Museum of Natural History, Vienna.
In front (sitting) is course co-organizer Dr. Vera M. F. Hammer
We spent the evening (and part of the night) in the impressive new
Terra Mineralia museum, receiving much information on the setup of
the museum. We also had the privilege to visit the not-yet-opened Asia
Hall, with its excellent mineral specimens and informative geoscientific
interpretive panels. Following the talks of the next morning, the group
split up to join one of three excursions: a visit to a crystal-growth lab,
a tour to the show mine Reiche Zeche / Alte Elisabeth, and a visit to a
collection of wooden models related to mining, handcrafted in the 18th
and 19th centuries. The group was impressed by and thankful for the
colourful program, which Karin Rank and Andreas Massanek had
arranged despite their tight schedule setting up the new exhibits at
Schloss Freudenstein. The next meeting, in two years, will take place in
the Museum of Natural History in Coburg.
The organizer’s aim was to put participants in a position to use the above
techniques in their own research. An overview of modern analytical
applications in gemmology was delivered through a number of talks
presented by invited experts in the field and, to a limited extent, by
course participants in 15-minute short talks. The seminars included
invited presentations by Thomas Hainschwang (Gemlab Gemological
Laboratory, Balzers, Liechtenstein), Wolfgang Hofmeister (Institut für
Edelsteinforschung, Idar-Oberstein & Mainz, Germany), Tobias Häger
(Johannes Gutenberg-Universität Mainz, Germany), Michael S.
Krzemnicki (SSEF Swiss Gemmological Institute, Basel, Switzerland) and
Lioudmila Tretiakova (GCAL Gem Certification and Assurance Laboratory,
New York, USA). The workshop also addressed future collaborative opportunities and allowed time for discussion on the development of a more
widespread and rigorous approach to achieving analysis. Such an
approach should leave little room for deception and should apply both
qualitative and quantitative functions that enable one to distinguish
quality gemstones and precious metals from stones and metals that are
counterfeit or have undergone chemical enhancements.
Renate Schumacher, Mineral Museum, University of Bonn
John McNeill, Durham University
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Mineralogical Society of Poland
www.ptmin.agh.edu.pl
4th Mid-European Clay Conference
– Zakopane, Poland
The 4th Mid-European Clay Conference was hosted by the Polish Clay
Group, which is functioning as the Clay Minerals Section of the
Mineralogical Society of Poland, on September 22–27, 2008. The conference gathered 180 participants from 27 European countries, Japan,
Australia and the USA. The conference programme included 6 plenary
lectures, 14 symposia with 64 oral presentations, and 101 posters.
Jan Środoń explaining the diagenetic history of the Podhale flysch
on top of the Wżar Hill (field trip 2)
Participants on field trip 3 in the Tatras covered by the first snow
(Gasienicowa Valley and Mount Kościelec)
Plenary lectures were delivered by Victor A. Drits (“Trans-vacant and
cis-vacant 2:1 layer silicates: Structural features, occurrence and identification”), Tamas G. Weiszburg (“Iron-dominated dioctahedral TOT
clay minerals: From nomenclature to formation processes”), Marian
Janek (“Application of terahertz time-domain spectroscopy for investigation of layered hydrosilicates”), Claude Forano (“Trends in hybrid
layered double hydroxides intercalation chemistry”), Derek C. Bain (“How
to succeed in publishing research in refereed journals”), and Goran
Durn (“Origin of terra rossa soils in the Mediterranean region”).
Participants on field trip 1 rafting through the Dunajec Gorge
Additionally, three post-conference field trips were held: (1) Lower
Jurassic black shales – the oldest flysch deposits of the Carpathians –
and their relation to geology of the Pieniny Klippen Belt (leader: Michał
Krobicki); (2) Diagenetic history of the Podhale flysch basin (leader:
Jan Środoń) and (3) The Tatras – Rocks, landforms, weathering and soils
(leaders: Ireneusz Felisiak, Irena Jerzykowska, Janusz Magiera, Łukasz
Uzarowicz).
During the meeting of representatives of the Mid-European Clay Groups,
held on 24 September 2008, the Deutsche Ton- und Tonmineralgruppe
(DTTG), representing the community of clay researchers and users in
Germany, Austria and Switzerland, was admitted as a new member. It
was decided that the next Mid-European Clay Conference will be held
in 2010 in Budapest (Hungary).
The conference proceedings were published in Mineralogia – Special
Papers, edited by the Mineralogical Society of Poland (free pdf version:
www.mecc08.agh.edu.pl). The field trip materials were published in
Geoturism 2(13), 2008.
Katarzyna Górniak
President of the MECC’08 Organizing Committee
Victor Drits delivering his plenary lecture
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Société Française de Minéralogie
et de Cristallographie
www.sfmc-fr.org
François Fontan Symposium
A tribute to François Fontan (1942–2007)
was held on 15 April 2009 at the Natural
History Museum of Toulouse (MHNT).
François passed away unexpectedly at
the age of 64, only a few weeks before his
retirement. He had been working at the
Laboratoire des Mécanismes et Transferts
en Géologie (LMTG, CNRS) of Paul Sabatier
University and the Observatoire MidiPyrénées in Toulouse for nearly 40 years,
and he had been collaborating with
MHNT since 1984. A rare mineral was
named for him (fontanite; see Deliens
and Piret 1992, European Journal of
Mineralogy 4: 1271).
François was a very generous and passionate person. The large attendance
at his tribute showed how much he is missed, as much as for his scientific
skills as for his kindness. The successful evening session, which proved
that the general public is strongly interested in mineralogy, would have
pleased him.
François’ commemorative day, in recognition of his research and his devotion to
enhancing the mineralogical patrimony
of both the museum and the university,
François Fontan (1942–2007)
was organized by his colleagues at LMTG
and MHNT, under the SFMC auspices.
The opening talk by Bernard Dupré (OMP Head) was devoted to the
varied scientific life of François. This was followed by a very moving slide
show presented by his friend P. Monchoux and an evocation by P. Dalous
of the fruitful collaboration between the museum and François, of his
passion for minerals and of his knowledge of plants, birds and other aspects
of nature.
Scientific lectures given by François’ friends, colleagues, and past students
from around the world underlined his influence in mineralogical
research, conducted mainly on phosphates and REE minerals in pegmatites.
The speakers were R.C. Wang (Nanjing University), A.-M. Fransolet and
F. Hatert (Liège University), E. Roda-Robles and F. Velasco (Basque Country
University), J.C. Melgarejo (University of Barcelona), and B. Moine and
S. Salvi (LMTG). Robert Martin (McGill University, Montreal) presented
the last major work of François, a book referencing minerals discovered
in France or named after French individuals (to be published by the
Mineralogical Association of Canada). Three public talks were presented: Y. Moëlo (IMN, Nantes) on the discovery of new minerals; G.
Calas (IMPMC, Paris) on the mysteries of mineral colours, forms and
properties; and G. Giuliani (LMTG, Toulouse and CRPG, Nancy) on the
fascinating economic and scientific aspects of emeralds.
Frédéric Béjina, Philippe de Parseval,
Pierre Monchoux, and François Martin
L’Or des Amériques, a wonderful exhibition
at the Muséum National d’Histoire Naturelle
in Paris, France • April 8, 2009 – January 10, 2010
The Muséum National d’Histoire Naturelle in Paris is currently
hosting the French-Canadian exposition L’Or des Amériques. While
the exhibition held earlier in Quebec City was more archeologically
focused, the MNHN show emphasizes the natural history of gold.
The quest for gold has left a deep imprint on the history of the
Americas. Five main topics are on display:
• The Nature of Gold,
with spectacular samples from
British Museum, the Paris
Museum of Natural History
the
and private collections
• The Flesh of the Gods,
with pre -C olumbian artifacts
from P eru, E cuador and
Colombia
• Dream Trackers, and the
gold rushes in C alifornia,
the K londike , Yukon and
Brazil
• Gold in French Guyana,
and the impact on geotopes
and biodiversity
• Gold, King of Metals,
with A ldwin ’s gold helmet
and gold -based jewelry, coins
and medicines
The main specimens are Feather of native gold crystals on quartz,
loaned from Museo del Oro Donatia mine, California, possibly
th
in Bogotá; Museo Arqueológico collected at the end of the 19 century
(ca. 12 × 10 × 5 cm, MNHN-155.64). The
Rafael Larco Herrera of Lima, specimen is likely the best of only three
Peru; Museo de América in recovered from this mine and was donated
Spain; Smithsonian in in 1955 by Louis Vésignié, one of the
Washington; Oakland Museum greatest French collectors. ©F. Farges/MNHN
of California; British Museum
in London; Dawson City Museum and other museums in Canada;
and many private collections, such as the Wayne Leicht and Ian
Bruce collections. Exceptional native gold specimens from Nevada,
California, British Columbia, Venezuela, Peru, and French Guyana
are displayed for the first time in Europe. From crystals to wires,
from veins to nuggets, gold presents a spectacular, fascinating
geo-diversity.
For more information, see www.mnhn.fr/museum/front/medias/
dossPresse/18170_OR_DP.pdf
For all SFMC and FFG joint
activities visit the website
http://e.geologie.free.fr.
Dedication to François Fontan at the Natural History Museum of Toulouse.
©F. Chastanet/OMP
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J une 2009
MEETING REPORTS
32nd Annual Winter Meeting
of the Mineral Deposit Studies
Group / Applied Mineralogy Group
This year, the Applied Mineralogy Group of the Mineralogical Society
co-convened the annual winter meeting of the Mineral Deposit Studies
Group. Camborne School of Mines (University of Exeter) hosted the
meeting on the newly built Combined Universities in Cornwall campus
near Falmouth. It attracted 120 delegates from universities and industry
with ~50% being postgraduate students. Following established tradition, the meeting was generously supported by industry (Barrick,
Anglo American, Rio Tinto, Golder Associates, SRK Consulting, Helio
Resources, and Boliden). The highlights of the meeting included
two field excursions, two special sessions, and a workshop entitled
‘The Application of Mineralogical Characterization to Processing and
Exploration’. The conference dinner was held at the National Maritime
Museum Cornwall in Falmouth.
The programme started with an excursion to the classical mining districts of West Cornwall, led by Robin Shail and Peter Scott. This trip
visited some of the most impressive locations within a landscape that
is now protected under the Cornish Mining World Heritage Site. After
a visit to Cape Cornwall, Botallack and Levant, the delegates enjoyed
a Cornish pasty lunch at Geevor mine, which was one of the last operating tin mines in Cornwall. The afternoon offered an opportunity to
go underground at Rosevale mine near Zennor.
Elizabeth Sharman receiving the Anglo American prize for the best
student poster from Chris Carlon
sulphide zinc deposits. Elizabeth Sharman (McGill University) received
the prize for the best student poster (sponsored by Anglo American)
for her study of multiple sulphur isotopes in the investigation of volcanogenic massive sulphides. Rob Thorne (Southampton University)
earned the prize for the best student oral presentation (sponsored by
Rio Tinto and presented by Barry Stoffell) on the Çaldağ nickel laterite
deposit in Turkey.
The main sessions of the meeting were followed by a workshop on the
application of mineralogical characterization to processing and exploration. The workshop offered an opportunity to visit the laboratories for
mineral processing and analysis at Camborne School of Mines. Richard
Pascoe (Camborne School of Mines) opened the workshop with a general introduction to mineral processing. This was followed by a presentation by Sarah Prout (SGS, Lakefield) on the use of mineralogical
characterization for exploration and processing at SGS. The practical
programme included demonstrations of the major industrial mineral
processing technologies (sensor-based sorting, shaking tables, hydrocyclones, dense-media separation, magnetic and electrostatic separation, flotation), as well as an introduction to modern technologies for
mineralogical characterization (including the QEMSCAN®) and analysis
(electron microprobe and chemical analysis).
The final day offered a joint excursion with the Ussher Society, led by
Richard Scrivener (British Geological Survey) and John Cowley (Wolf
Minerals), to the Hemerdon Ball tungsten mine on the edge of Dartmoor
in South Devon. The mine site is under licence to Wolf Minerals and
scheduled to resume production of tungsten and tin in 2010. It was
in production up until 1944 and is considered to contain one of the
largest unexploited tungsten deposits in the world.
Tony Clarke demonstrating the flotation of sulphides to workshop participants
Jens C. Andersen
Member of the Organizing Committee
The highlights of the academic programme were the two special sessions. Robert Schouwstra (Anglo Research, South Africa) gave the keynote address in the ‘Mineralogy in Mineral Processing’ session. His
presentation explored the need for mineralogical characterization in
the extractive industries, with particular examples from the South
African platinum industry. The other presentations served to highlight the profound significance of automated mineral characterization
(via QEMSCAN® or MLA) in modern mining operations (ore and waste
characterization, as well as process optimization). In the ‘Ore Deposits
Related to Acid Magmatism’ special session, Michel Cuney (CNRS,
France) presented the keynote address on uranium deposits related to
granitoids. His talk highlighted the significance of granite petrogenesis
for uranium exploration. The session reflected the broad spectrum of
ore deposits related to acid magmatism. The general sessions included
presentations on a wide variety of mineral deposit types and locations,
from the traditional sulphide-related resources to laterite ores and nonE lements
193

You have a position to fill at your
­department or lab? Advertise it in
Elements or on the Elements website.

Looking for a job?
Check our website
www.elementmagazine.org
J une 2009
MEETING REPORTS
Minerals, Inclusions
and Volcanic
Processes
Mineralogical Society of
America and Geochemical
Society Short Course
Minerals and their inclusions have long been
used to understand magmatic systems (Sorby
1858; Roedder 1965). New interest relative to
volcanic systems was sparked by Anderson and
Wright (1972), Eichelberger (1975), Anderson
(1976), and Dungan and Rhodes (1978), among
others. Recent advances in microanalytical
techniques (e.g. Davidson et al. 1990) have
greatly accelerated this work, highlighting the
potential for improved views of magma
plumbing systems (Marsh 1996). The short
course “Minerals, Inclusions and Volcanic
Processes”, was organized by us to summarize
where these earlier strands of research have
branched, with the hope of initiating new collaborations based on an alliance of complementary techniques. The prospects for such
were perhaps indicated by the broad range of
backgrounds of the 207 attendees at the short
course held on December 13–14, 2008, in San
Francisco.
Fluid inclusions in quartz. Photo C. Schnyder and O. Bachman
Julia Hammer began the session with a review
of crystal kinetics. She illustrated the importance of undercooling in forming various mineral textures—including melt inclusions. She
also noted that crystal growth rates decrease
with time as crystals and liquid approach equilibrium, implying that true instantaneous
growth rates are perhaps only captured in the
earliest moments of dynamic experiments.
Keith Putirka discussed mineral–melt-based
thermometers and barometers, with an emphasis
on tests of equilibrium. Putirka showed that
dynamic experiments can be used to test our
“tests of equilibrium” and that independent
tests or, better yet, independent P–T estimates,
are crucial to narrowing uncertainty. Lawford
Anderson showed applications of thermoE lements
Plagioclase from Arenal Volcano, Costa Rica. Nomarski
image from M. Streck
barometry to granitoids in California. In some
plutons, Ti-in-zircon thermometry yields temperatures ranging from the granite solidus to
the liquidus, but Anderson warned that though
these T ranges may be real, the activities of
trace components are sensitive to mineralogy
and liquid composition and new experiments
are needed. Thor Hansteen and Andreas Klügel
reviewed methods to estimate pressures from
fluid inclusions. These estimates can be very
precise if inclusions are homogeneous and isochoric, and if they remain closed (“Roedder’s
Rules”). But even where closure is violated,
Hansteen and Klügel showed that frequency
plots of P estimates yield peaks that can be
correlated to depths of magma storage. An additional promising result is that fluid inclusions
and mineral–melt equilibria in some instances
yield similar pressure ranges.
Jon Blundy presented a multifaceted study of
Mount St. Helens, performed in collaboration
with Katherine Cashman. There, mineral textures, melt inclusions, and several thermometers and barometers yield an internally consistent picture of the magma plumbing system
and degassing rates. Blundy also showed a P–T
diagram illustrating gradients in crystallinity
and volatile saturation, emphasizing that minerals may record this variability, with T being
a proxy for proximity to a chamber wall.
Malcolm Rutherford summarized magma ascent
rates as determined by experimental investigations. Magma ascent rates from amphibolebreakdown reactions are similar to those from
decompression-induced crystallization (ca. 0.2
m/s at Mount St. Helens), and within an order
of magnitude of estimates derived from seismicity (0.6 m/s at Mount St. Helens). Ascent
rates are also correlated with explosivity, indicating an important petrologic forensic tool.
Nicole Métrich and Paul Wallace examined
volatile contents and showed that fluid inclusions
yield higher pressures than melt inclusions
194
and that inclusions from one sample can yield
a range of saturation pressures. This implies
that inclusion capture is concurrent with
magma rise and that melt inclusions record
shallower-level degassing and crystallization.
Gordon Moore showed that CO2 and H 2O solubilities are sensitive to melt composition and
are interdependent, and he noted that saturation models thus should not be extrapolated.
The models of Newman and Lowenstern (2002)
(VolatileCalc) and Papale et al. (2006) account
for compositional variations in mixed CO2 –
H2O-bearing melts. Both work well for rhyolites, while the Papale et al. model is better for
mafic systems.
Adam Kent began the second day discussing
how melt inclusions capture a wider range of
complexity than revealed by whole rocks. He
showed how Ca/Al ratios can differentiate
whether melt inclusions trap far-field or nearfield melts (Faure and Schiano 2005), and he
concluded that most trap far-field compositions. Frank Ramos and Frank Tepley summarized isotopic microsampling procedures. They
showed examples where individual crystals
yield cores in isotopic disequilibrium and rims
in equilibrium with adjacent glass. Intergrain
heterogeneity may result from age differences
and/or mixing between two components. Ilya
Bindeman surveyed oxygen isotopes from
single crystals and demonstrated how O isotopes are especially powerful for identifying
hydrothermally altered components in magmatic systems. And because O diffuses slowly,
heterogeneity is preserved over long time­
scales. Kari Cooper and Mary Reid reviewed
timescales from U-series crystal ages. At Lacher
See, some flows yield identical mineral and
whole-rock eruption ages, but early evolved
flows (presumably from the top of the magma
chamber) host minerals that are 17 ky older
than recorded by the whole-rock system—perhaps indicating a minimum subterranean life
span of the eruptive system. Fidel Costa provided an overview of timescales from diffusion
profiles. Diffusion profiles yield much shorter
timescales than U-series methods; very young
ages (mostly <100 y) reflect entrainment of
J une 2009
MEETING REPORTS
older crystals and periods of crystal overgrowth.
The Bishop Tuff, for example, yields diffusive
timescales of ∼100 y, reflecting late-stage reheating
and overgrowth.
Martin Streck reviewed mineral textures and
emphasized that genetic terms like“xenocryst”
and “antecryst” lose meaning when individual
crystals are composites of multiple growth (and
dissolution) events. Optical methods reveal
different types of zoning and, at Arenal, yield
a precise enumeration of five magmatic events.
The following discussion, however, indicated
that fewer students are being trained to use a
petrographic microscope. Pietro Armienti
reviewed crystal size distributions (CSDs); he
showed that, properly measured, CSDs are
independent of sampling scale (from 7 cm2 to
>800 cm2 at Mt. Etna). At Mt. Etna, near-vent
samples have CSDs identical to downstream
samples, indicating that crystallization occurred
prior to eruption. Armienti also showed that
peaks in CSDs may indicate degassing.
ReferenceS
George Bergantz presented work done in collaboration with Olivier Bachman on the physical mechanisms of magma mixing. Bergantz
noted that the “Daly gap” in SiO2 is found in
some arcs, while others are strikingly homogeneous (monotonous intermediates of Hildreth
1981). Sluggish convection can create heterogeneities as plumes produce thermal/chemical
gradients, especially if the Reynolds number
is low (Re <1). At high Re (>104), heterogeneities
can also be produced if convection is limited
to a single overturn. Monotonous intermediates
may reflect multiple overturn events, despite
their being SiO2- and crystal-rich (and so resistant
to convection).
Although recent advancements spurred the
organization of the short course and publication of the accompanying volume, there remains
a clear need for additional work. New experimental data are needed to better understand
volatile saturation, equations of state for mixed
fluids, and crystal growth. Many current lines
of investigation are complementary and can
Anderson AT (1976) Magma mixing:
petrological process and volcanological
tool. Journal of Volcanology and
Geothermal Research 1: 3-33
Dungan MA, Rhodes JM (1978)
Residual glasses and melt inclusions
in basalts from DSDP legs 45 and
46: Evidence for magma mixing.
Contributions to Mineralogy and
Petrology 67: 417-431
Anderson AT, Wright TL (1972)
Phenocrysts and glass inclusions
and their bearing on oxidation
and mixing of basaltic magmas,
Kilauea Volcano, Hawaii. American
Mineralogist 57: 188-216
Eichelberger JC (1975) Origin of andesite
and dacite: Evidence of mixing at
Glass Mountain in California and
at other circum-Pacific volcanoes.
Geological Society of America
Bulletin 86: 1381-1391
Davidson JP, de Silva SL, Holden P,
Halliday AN (1990) Small-scale
disequilibrium in a magmatic
inclusion and its more silicic host.
Journal of Geophysical Research
95B: 17661-17675
Faure F, Schiano P (2005) Experimental
investigation of equilibration conditions during forsterite growth
and melt inclusion formation. Earth
and Planetary Science Letters 236:
882-898
Check Geochemical News july 2009
for a longer version of this report.
be used to great effect in concert: U-series ages
appear to indicate the earliest stages of magma
generation, while diffusion-profile ages inform
us of later transport. Mineral–melt barometers
inform us about the deeper parts of volcanic
systems, and volatile-saturated equilibria
inform us of the shallower part; fluid inclusions appear to record both, perhaps with
higher precision. An alliance of methods can
provide key tests of our assumptions and interpretations. To the extent that such tests yield
a coherent picture of a volcanic system, the
advances outlined at the short course and in
the volume illustrate the promise of petrology
and mineralogy for affording fundamental
tests of the evolution of magma storage, transport, and eruption.
Keith D. Putirka
California State University, Fresno,
and Frank J. Tepley III
Oregon State University
Hildreth W (1981) Gradients in silicic
magma chambers: Implications for
lithospheric magmatism. Journal
of Geophysical Research 86: 1015310192
Papale P, Moretti R, Barbato D (2006)
The compositional dependence of
the saturation surface of H 2O+CO2
fluids in silicate melts. Chemical
Geology 229: 78-95
Marsh BD (1996) Solidification
fronts and magmatic evolution.
Mineralogical Magazine 60: 5-40
Roedder E (1965) Liquid CO2 inclusions
in olivine-bearing nodules and
phenocrysts from basalts. American
Mineralogist 50: 1746-1782
Newman S, Lowenstern JB (2002)
VolatileCalc: a silicate melt–H 2O–
CO2 solution model written in
Visual Basic for Excel. Computers
& Geosciences 28: 597-604
Sorby HC (1858) On the microscopic
structures of crystals, indicating
the origin of minerals and rocks.
Geological Society of London
Quarterly Journal 14: 453-500
ELEMENTS IN THE CLASSROOM
I
am an associate professor of geochemistry in a geological engineering school in France, the Institut Polytechnique LaSalle
Beauvais. I enjoy reading Elements magazine and have used it in my
geochemistry class. This semester, I decided to make further use
of Elements in my hydrogeochemistry (master 1) class. I chose four
themes, arsenic, phosphates, nanoparticles, and uranium, that have
been covered by Elements issues “Arsenic”, “The Nuclear Fuel Cycle”,
“Energy”, “The Critical Zone”, “Phosphates and Global Sustainability”,
“Carbon Dioxide Sequestration” and “Nanogeoscience.” Each student
was partnered with a classmate and asked to read an article and make
a short presentation (10 minutes) about it to the whole class.
Students were very pleased with the selected subjects and enjoyed
reading and listening about each broad theme. Even if most of my
students will specialize in Environment and Development, they have
realized how chemistry and even physics are intimately linked with
geology and how they need to be familiar with field geology. Thus,
the subjects of phosphate and arsenic were more amenable to them,
and the nanoparticle theme required a little more preparation. In the
future, I hope to expand such presentations to the entire master 1
level and involve students from the “Energy and Minerals” program.
I have enclosed a photograph of my class.
Olivier Pourret
Institut Polytechnique Lasalle Beauvais, France
E lements
195
J une 2009
OUTREACH
Why Study Mineralogy?
In recent decades, mineralogy has evolved considerably. This is due in
part to the development of new instrumentation of enormous precision
and to the vastly greater powers of computation now available. It is also
due to the expansion of the subject: mineralogy now spills over into the
realm of societal issues, in particular, environmental studies. Here mineralogists have let down their guard, allowing their expertise to become
undervalued and too often overshadowed by the pronouncements of
lawyers, politicians, and administrators.
I open the undergraduate mineralogy course that I now teach wearing
an elegant white vest with red and black trim (see photo). I’ll return to
the significance of this garment shortly. My two-hour lecture commences with the usual introductory topics: What is mineralogy? How
does it relate to the other Earth sciences? And so on. Next I pass directly
to the core of my lecture: Why study mineralogy? To let the cat out of the
bag right off, in my view a central purpose is to offer guidance to lawyers,
politicians, and administrators who widely display remarkable ignorance
of matters mineralogical. This advice allows me to launch into the
asbestos controversy, a topic as bizarre and irrational as the Y2K catastrophe that threatened civilization a decade ago. Remember that one?
For openers, I point out that asbestos does not exist, at least not to a
mineralogist. Asbestos is not a mineral; it is a commercial term for a
variety of unrelated minerals with an asbestiform habit (i.e. in fibers with
a certain degree of flexibility). This allows me to introduce the nature
of polymorphism (e.g. antigorite, chrysotile) to my students. Next comes
white versus blue or brown asbestos: the amphiboles. This presents the
opportunity to bring up the concept of mineral groups and to discuss
the distinctiveness of individual members. Then I dive into the bio-geomedical literature (a wonderful occasion to demonstrate to my students
the importance of journal articles). Here one can read about the stark
contrast in toxicity between asbestiform minerals of the serpentine
group (chiefly chrysotile) and the amphibole group (chiefly riebeckite
and amosite). Further along, the student can learn that chrysotile is
rather harmless. It is resorbed quickly by human tissue, leading to no
buildup of lung burden. Dust from brake shoes and pads contains no
chrysotile; the intense and concentrated heat due to friction upon
braking reduces the mineral to a brown amorphous substance.
My introductory lecture next moves on to talc. To set the scene, I disperse a small cloud of the mineral at the front of the classroom from
a can of “baby powder.” It is an opportunity to point out that talc is
indeed a mineral—an unusual mineral in that it allows little ionic substitution and thus deviates little from its ideal formula. This is a handy
point to elaborate on the definition of a mineral. Also, I here mention
that talc is a phyllosilicate and is thus related to mineral groups (a concept brought up just a bit earlier) such as the micas, clays, serpentines,
chlorites, and so on. This past year, my students were told to keep the
following short article in mind. It appeared in August, 2008, in Le Devoir,
one of Québec’s most prestigious newspapers.
“Beware of talc. A group of doctors, scientists and consumer-defense
organizations yesterday demanded that American health authorities
immediately ban cosmetic products with talc because of the carcinogenic
nature of the mineral as revealed by several scientific studies. According
to the Cancer Prevention Coalition (an arm of the American Association
of Public Health), ‘talc poses a deadly risk of ovarian cancer in women,’
the incidence of which has risen 30% since 1975. With more than
15,000 deaths each year attributed to it, talc must be removed from
drugstore shelves, according to the coalition which, in passing, deplores
that for years the Food and Drug Administration has refused to require
that warning labels be affixed to the packaging of these cosmetics.”
On their midterm exam, the article reappeared, and I asked them to
analyze it (1) from the viewpoint of its logic, and (2) as a mineralogist.
Quite frankly, if by the end of their undergraduate years our students
are unable to assess such mineralogical nonsense and explain clearly
to lawyers, politicians, administrators, and the public at large why such
pronouncements in the media are claptrap, we have failed as teachers
of mineralogy.
E lements
Tomas Feininger in his white vest
At the age of 19, I worked in the asbestos industry, in a shop shaping
and fitting blocks of asbestos to friction bands and clutches for bulldozers,
locomotives, and steam shovels. It was really dirty work. The dust from
my job—grinding the edges of the asbestos blocks flush after riveting
them to their bands and discs—was so dense that one could not see
from one side of the shop to the other, a distance of about 10 or 15 meters.
We wore no masks. It was, in fact, the suffocating dust (and not the
mere presence of chrysotile) throughout the asbestos industry in the
1950s and 1960s, in mines, mills, and product shops, that was the cause
of widespread lung disease. The same held for flour mills, cotton-carding
shops, coal mines, and other dusty industrial venues, where lung disease
was no less rampant than in the asbestos industry.
My interest in these issues began some 20 years ago when my (then)
ten-year-old daughter came to my office and was intrigued by and picked
up a sample of chrysotile with 4 cm long fibers. She asked: “Daddy, this
is beautiful, what is it?” When I told her that it was chrysotile “asbestos,”
she reacted as if faced by a deadly snake. Recoiling, she said something like
“Daddy, how can you keep something so dangerous in your office?” Then
and there I realized that we, as mineralogists, had a battle on our hands.
Toward the conclusion of my lecture, I point out that much of the mediadriven assault against mineralogy is fueled by the notion of the no-risk
society. This is absurd. No such utopia is attainable. Frankly stated, life is
a fatal condition contracted at birth and transmitted sexually. Bon voyage!
Let me now return to my white vest. Excluding the thin coloured trim,
this garment is made entirely of chrysotile. At the close of my lecture,
I ask the students what they think of my vest. The opinions are invariably favourable. I then request that one of them come forward to feel
the cloth. When I ask what is the nature of the cloth, no one in the
room has an answer. When I reveal that it is chrysotile asbestos, I am
met by disbelieving stares of amazement. I go on to recount how this
material has saved many lives and that it promotes our security by
protecting firemen in their work, that New York’s World Trade Center
towers might still be standing if the steel structure had been insulated
with asbestos (as had been recommended by engineers before construction began), and that the Swissair plane that went down in Nova Scotia
in 1998 with terrible loss of life would not have crashed had its wiring
been insulated with chrysotile rather than with the artifical product
used in its place because of the asbestos ban. In short, I refer to chrysotile
as a “Don de Dieu.”
Now, at 73, I have probably taught my last mineralogy class. Enough
is enough. Nevertheless, I take this occasion to ask earnestly that those
who follow take proactive positions on legal, political, and administrative
issues where mineralogy has a role. There are many, and we share a
common responsibility.
196
Tomas Feininger, Université Laval, Québec
J une 2009
BOOK REVIEW
Laser Ablation ICP–MS in the Earth Sciences:
Current Practices and Outstanding Issues*
Laser ablation ICP–MS has been an important
analytical tool in the Earth sciences since the
early 1990s. Eight years ago, a workshop was
held in St. John’s, Newfoundland, Canada, on
the topic. As a result of the workshop, a collection of papers describing the technique and
its application to trace element analysis, along
with a brief consideration of isotope ratio measurements, was published (LA–ICP–MS in the
Earth Sciences: Principles and Applications,
Mineralogical Association of Canada short course
volume 29). The present volume, dedicated to
current practices and outstanding issues, shows
how much this method has matured since
2001. Recent developments in laser ablation
procedures, aerosol formation, isotope fractionation, matrix effects, data acquisition and
reduction for trace element and isotope ratio
measurements are discussed in a well-presented,
pedagogical way. This volume highlights the
versatility of LA–ICP–MS and its applications
in the various fields of geoscience.
The Mineralogical Association of Canada Short
Course Series volume 40, Laser Ablation ICP–MS
in the Earth Sciences: Current Practices and
Outstanding Issues, presents the current state
of knowledge and potential future developments in this versatile analytical technique.
Compared to the previous publication, the new
volume has a greater focus on isotope ratio
measurements, which came to the fore with
the development of multiple collector ICP–MS.
The editor, Paul Sylvester (Memorial University,
Newfoundland), has gathered a collection of
papers from leading scientists that will be
useful to anybody interested in LA–ICP–MS
techniques, from the student to the most expert
researcher in the field.
H. Longerich (chapter 1) inaugurates the new
volume, as he did in the earlier one. He pulls
the instrument apart and takes the reader on
a virtual laboratory tour, explaining the use
of each component. A comparison of the different laser ablation systems and mass spectrometers is made, from the point of view of
the user’s application and budget.
D. Günther and J. Koch (chapter 2) review the
effects of the formation of aerosols generated
by laser ablation and their impact on elemental
fractionation in LA–ICP–MS, and D. Bleiner
and Z. Chen (chapter 3) present the results of
a computer simulation of laser ablation elemental microanalysis. Both of these chapters
show that the ability to visualize aerosol
* Sylvester P (ed) (2008) Laser Ablation ICP–MS
in the Earth Sciences: Current Practices and
Outstanding Issues. Mineralogical Association
of Canada short course volume 40, 364 pages
ISBN 978-0-921294-49-8
E lements
guide to depth profiling and to trace element
and isotope mapping applications. Using trace
element and isotope mapping of speleothems,
otoliths, and feldspars as examples, they show
that the laser ablation system and the sample
cell are critical for high-resolution images.
behavior in the sample cell and the tubing,
which depends on the gas medium and the
laser ablation system, is of critical importance.
Ingo Horn (chapter 4) compares results obtained
using fs and nanosecond(ns) laser interactions
with different geological matrices. Data on an
impressive collection of in situ stable isotope
ratios (Fe, Cu, and Si isotopes), acquired using
an femitosecond(fs) laser ablation system, are
provided, thus giving us a glimpse into our
possible analytical future.
P. Sylvester (chapter 5) highlights the versatility of the technique for measuring trace elements and reviews the operating conditions
necessary to minimize matrix effects. He shows
that, unless high precision is required and providing that the samples and the standard are
reasonably similar, precision and accuracy are
easily better than 10%.
J. Košler (chapter 6) reviews and compares two
laser ablation sampling modes (single spot versus
raster). The use of scanning ablation is preferred, when possible, since it improves data
quality and allows a visual control of the
ablated area. N.J. Pearson, W.L. Griffin, and
S.Y. O’Reilly (chapter 7) point out that many
factors influence accuracy and precision for
precise isotope ratio measurements. After a
detailed review of different methods, they suggest several techniques for mass fractionation
correction, mainly based on Hf isotope ratio
measurements. C. McFarlane and M. McCulloch
(chapter 8) show that it is possible to measure
the in situ Nd isotope composition of various
common LREE-enriched accessory phases,
such as apatite, allanite, and monazite. This
technique is best applied when high spatial
resolution analysis and high sample throughput
are required, such as in provenance studies.
J. Woodhead, J. Hellstrom, C. Paton, J. Hergt,
A. Greig, and R. Maas (chapter 9) present a
197
K.P. Jochum and B. Stoll (chapter 10) review
the available reference materials for trace element and isotope ratio measurements in various matrices. They highlight the general lack
of suitable reference materials for precise and
accurate measurements and promote their very
useful GeoReM website. S. Jackson (chapter 11)
reviews the different calibration techniques for
trace element analysis by LA–ICP–MS. Trace element analyses of diamond and sulfides are presented as examples. He also shows that accurate data can be generated when elements
share the same fractionation index, even with
poorly matrix-matched standards. T. Pettke
(chapter 12) discusses the measurement of elemental and isotope ratios in fluid inclusions.
The main limiting factor in the calibration
technique is the uncertainty of the internal
standard value. P.R.D. Mason, I.K. Nikogosian,
and M.J. van Bergen (chapter 13) review the
different calibration techniques for the analysis of major and trace elements in melt inclusions. They also compare this technique with
more traditional microanalytical techniques,
such as SIMS/EPMA.
A. Simonetti, L. Heaman, and T. Chacko (chapter
14) show the results of in situ U–Pb dating of
zircon, monazite, and perovskite in petrographic thin sections using multiple discretedynode secondary electron multipliers. A.K.
Souders and P. Sylvester (chapter 15) show the
use of multiple continuous-dynode channeltron ion counters for the analysis of common
lead in silicate glass. They review all possible
errors related to the stability and linearity of
ion counters, mass bias corrections, and interference corrections and then show some results
using international standards. M.S.A. Horstwood
(chapter 16) presents a unique paper dedicated
to data reduction strategies and error propagations inherent to LA–(MC)–ICP–MS. This is a
very interesting attempt at a comprehensive
and unifying calculation strategy for isotope
measurements using this technique. Finally
the volume includes nine of the most common
data reduction software programs available for
trace element and/or isotope ratio measurements.
This short course volume is available for a very
modest price compared to the value of its contents. Short course volume 40 should stand on
the shelf beside your favorite analytical system,
and it should be routinely consulted by anybody
remotely interested in laser ablation (MC) –
ICP–MS. The earlier volume, short course
volume 29, is also included on a CD accompanying the volume.
Yann Lahaye
GTK, Espoo, Finland
J une 2009
CALENDAR
2009
September 1–3 The Mineralogical
Society’s Annual Meeting, in conjunction
with the German and French Mineralo­
gical Societies: MAPT – Micro-Analysis,
Processes, Time, Edinburgh, Scotland.
Details: Simon Harley, e-mail: s.harley@
ed.ac.uk; web page: www.minersoc.org/
pages/ meetings/meetings.html
September 1–4 AGU Chapman Confer­
ence on the Biological Carbon Pump of
the Oceans, Brockenhurst, Hampshire,
England. Details: Richard Lampitt; e-mail:
[email protected]; web page: www.
agu.org/meetings/chapman/2009/dcall
September 6–9 3rd International
Symposium on Advanced Micro- and
Mesoporous Materials, Albena, Bulgaria.
Web page: micro2009.bg-conferences.
org/micro2009
September 6–9 4th International
Conference on the Environmental Effects
of Nanoparticles and Nanomaterials,
Vienna, Austria. Web page:
http://nano2009.univie.ac.at
September 6–10 XII Conference on the
Physics of Non-Crystalline Solids (XII
PNCS), Foz do Iguaçu, PR, Brazil. Web
page: www.pncs-crystallization.com.br
September 7–10 MinPet 2009 & 4th
Mineral Sciences in the Carpathians
Conference, Budapest, Hungary. Web
page: www.minpet2009mscc.org
September 7–11 Geoanalysis 2009,
Drakensburg Region, South Africa.
E-mail: [email protected];
web page: www.geoanalysis2009.org.za
September 9–11 Geoitalia 2009
– VII Italian Forum of Earth Sciences,
Rimini, Italy. Details: Lorenza Fascio;
e-mail: [email protected];
web page: www.geoitalia.org
Valley and the Volcanic Tableland,
California (GSA Field Forum), Bishop,
CA, USA. Details: David A. Ferrill; e-mail:
[email protected]; web page: www.
geosociety.org/fieldForums/09calif.htm
October 22–25 Joint Conference: the
Asian Crystallographic Association with
the Chinese Crystallography Society
(AsCA’09), Beijing, PRC. Web page:
www.ciccst.org.cn/asca09
September 13–19 8th International
Carbon Dioxide Conference, Jena,
Germany. Details: Felix Angermüller;
e-mail: [email protected];
web page: www.conventus.de/icdc8/
October 25–29 First World Young
Earth Scientists Congress 2009, Beijing,
PRC. Details: Elyvin Nkhonjera; e-mail:
[email protected]; web page:
www.yescongress2009.org/index.php
September 14–18 13th International
IUPAC Conference on High Tempera­
ture Materials Chemistry, Davis, CA,
USA. Details: Alexandra Navrotsky;
e-mail: [email protected]; web page:
http://neat.ucdavis.edu/HTMC%2D13
October 25–30 Materials Science &
Technology 2009 Conference and
Exhibition – MS&T ’09 combined with
the American Ceramic Society (ACerS)
111th Annual Meeting, Pittsburgh, PA,
USA. Web page: www.matscitech.org/
2008/pastmtgs.html
September 17–18 International
Symposium on Mineralogy, Environment
and Health, Marne-la-Vallée, France.
Details: Stéphanie Rossano (rossano@
univ-paris-est.fr) or Eric van Hullebusch
([email protected]);
web page: www.univ-mlv.fr/master_
geoenv/symposium2009.html
November 10–12 3rd Russian Conference
on Organic Mineralogy with International
Participation, Institute of Geology,
Syktyvkar, Russia. Details: Olga Kovaleva;
e-mail: [email protected];
web page: www.minsoc.ru/confs
September 19–26 The International
Committee for Coal and Organic
Petrology (ICCP) and The Society for
Organic Petrology (TSOP) Joint Annual
Meeting, Gramado/Porto Alegre, Brazil.
E-mail: [email protected]; web
page: www.ufrgs.br/ICCP_TSOP_2009
September 21–23 Geological Society
William Smith Meeting: Environment,
Pollution & Human Health, London,
England. E-mail: e.valsami-jones@nhm.
ac.uk; web-page: www.minersoc.org/
pages/groups/emg/emg.html
December 14–16 Clay Minerals Group
of the Mineralogical Society Annual
Meeting, Newcastle, UK. Details: Claire
Fialips; e-mail: [email protected];
web page: www.minersoc.org/pages/
groups/cmg/cmg.html#fialips
September 21–25 Clays, Clay Minerals
and Layered Materials 2009, Moscow,
Russia. Web page: www.cmlm2009.ru
December 14–18 AGU Fall
Meeting, San Francisco, CA, USA.
E -mail: [email protected]; web
page: www.agu.org/meetings
2010
September 25–27 New England
Intercollegiate Geological Conference
(NEIGC), Lyndonville, VT, USA. Web
page: w3.salemstate.edu/~lhanson/NEIGC
September 9–13 Low δ18O Rhyolites
and Crustal Melting: Growth and
Redistribution of the Continental
Crust, Twin Falls, ID, and Yellowstone
National Park, WY, USA. Details: Peter
Larson; e-mail: [email protected]; web
page: www.geosociety.org/
penrose/09idaho.htm
250th
September 10–13 9th International
Symposium on Crystallization in Glasses
and Liquids (Crystallization 2009),
Foz do Iguaçu, PR, Brazil web page:
www.pncs-crystallization.com.br
September 11 SMMP 2009: The Society
of Mineral Museum Professionals
Meeting, Denver, CO, USA. Web page:
www.agiweb.org/smmp/meetings.htm
September 13–17 5th International
Workshop on Infrared Microscopy and
Spectroscopy with Accelerator Based
Sources, Banff, Alberta, Canada. Web
page: www.lightsource.ca/wirms2009
September 13–17 Annual Meeting of
the German Mineralogical Association
(DMG), Halle/Saale, Germany. E-mail:
[email protected]; web page:
www.DMG-Meeting.de
September 13–18 European Planetary
Science Congress (EPSC) 2009,
Potsdam, Germany. Web page:
http://meetings.copernicus.org/epsc2009
September 13–19 Structure and
Neotectonic Evolution of Northern Owens
September 27–October 4 The
Anniversary of Volcán Jorullo’s Birth in
Michoacán, México, Morelia, Michoacán,
México. Web page: www.geofisica.
unam.mx/vulcanologia/jorullo
September 30–October 2 Alpine
Ophiolites and Modern Analogues, Parma,
Italy. E-mail: [email protected]; web
page: www.alpineophiolite2009.org
October 4–9 Tectonic Development of
the Amerasia Basin, Banff Centre, Alberta,
Canada. Details: Victoria Pease (vicky.
[email protected]) or Lawrence Lawver
([email protected]); web page:
www.geosociety.org/penrose/09banff.htm
October 9–12 Fifth International
Symposium on Mineral Diversity - Research
and Preservation, Sofia, Bulgaria. Web page:
www.agiweb.org/smmp/MinDiv5.pdf
October 18–21 Geological Society of
America Annual Meeting, Portland, OR,
USA. E-mail: [email protected];
web page: www.geosociety.org/
meetings/2009
October 18–23 XII Brazilian Geoche­
mical Congress/VIII International
Symposium on Environmental
Geochemistry, Ouro Preto, Brazil. Web
page: www.12cbgq.ufop.br/12cbgq
E lements
November 15–19 AAPG 2009
International Conference and Exhibition,
Rio de Janeiro, Brazil. Web page:
www.aapg.org/meetings
November 30–December 4 MRS Fall
Meeting, Boston, MA, USA. Web page:
www.mrs.org/s_mrs/index.asp
September 24–27 Magmatism and
Metamorphism in the Holy Cross
Mountains, XVI Meeting of the
Petrology Group of the Mineralogical
Society of Poland and VII Meeting of
the Mineralogical Society of Poland,
Świȩty Krzyż, Poland. Web page: prac.
us.edu.pl/~ptmin2009
September 9–12 XXIX Meeting of the
Sociedad Española de Mineralogía
(SEM), Salamanca, Spain. Web page:
www.usal.es/~sem09
November 11–14 Volcanoes, Landscapes
and Cultures, Catania, Italy.
E-mail: [email protected];
website: www.etnacatania2009.com
January 3–9 2010 Winter Conference
on Plasma Spectrochemistry, Sanibel,
FL, USA. E-mail: [email protected].
edu; web page: http://icpinformation.org/
2010_Winter_Conference.html
January 5–7 Sixth International
Conference on Environmental, Cultural,
Economic and Social Sustainability,
University of Cuenca, Ecuador. E-mail:
[email protected]; web page:
www.SustainabilityConference.com
January 10–15 Gordon Research
Conference: Origin of Life, Galveston, TX,
USA. Web page: www.grc.org/programs.
aspx?year=2010&program=origin
January 24–29 34th International
Conference and Exposition on Advanced
Ceramics and Composites, Daytona Beach,
FL, USA. Web page: www.ceramics.org/
meetings/index.aspx
February 4–7 6th International Dyke
Conference (IDC-6), Varanasi, India.
E-mail: [email protected] or
[email protected]; web page:
www.igpetbhu.com
March 1–5, 41st Lunar and Planetary
Science Conference (LPSC 2010), The
Woodlands, TX USA. Details forthcoming
239th
March 21–25
ACS National
Meeting & Exposition, San Francisco,
CA, USA. Web page: www.acs.org
198
April 5–9 MRS Spring Meeting,
San-Francisco, CA, USA. Web page:
www.mrs.org/s_mrs/index.asp. Details:
Ian Graham, e-mail: [email protected];
April 6–9 13th Quadrennial IAGOD
Symposium 2010, Giant Ore Deposits
Down-Under, Adelaide, Australia. Web
page: www.geology.cz/iagod/activities/
symposia/adelaide-2010
April 18–21 2010 AAPG Annual
Convention and Exhibition, New Orleans,
LA, USA. www.aapg.org/meetings
May 19–28 American Crystallographic
Association (ACA) Annual Meeting,
New Orleans, LA, USA. Web page:
www.AmerCrystalAssn.org
May 31–June 4 Cities on Volcanoes 6
- Tenerife 2010, Canary Islands, Spain.
Details: Dr. Nemesio M. Pérez; e-mail:
[email protected]
June EURISPET: High-Temperature
Metamorphism and Crustal Melting,
Padova, Italy. Details: Bernardo Cesare;
e-mail: [email protected];
web page: www.eurispet.eu
June 6–11 SEA-CSSJ-CMS Trilateral
Meeting on Clays, Madrid, Spain. Web
page: wwwsoc.nii.ac.jp/
cssj2/2010TrilateralClays1.pdf
June 6–11 Gordon Research
Conference: Crystal Engineering,
Waterville Valley, NH, USA. Web page:
www.grc.org/programs.aspx?year=2010
&program=crystaleng
June 6–11 Gordon Research
Conference: Natural Gas Hydrate
Systems: Hydrate-Sediment-Fluid
Interactions at Pore to Regional Scale,
Waterville, ME, USA. Web page: www.
grc.org/programs.aspx?year=2010&prog
ram=naturalgas
June 13–18 Gordon Research
Conference: Environmental Bioinorga­
nic Chemistry: Elements In The
Environment, from Prokaryotes to
Planets, Newport, RI, USA. Web page:
www.grc.org/programs.aspx?year=2010
&program=envbiochem
June 14–18 Goldschmidt 2010,
Knoxville, TN, USA. Web page: www.
geochemsoc.org/news/conferencelinks
June 21–24 11th International
Platinum Symposium, Sudbury, Canada.
Details: Prof. Michael Lesher; e-mail:
[email protected]; web page:
www.11IPS.laurentian.ca
June 27–July 2 Gordon Research
Conference: Research at High Pressure,
Holderness, NH, USA. Web page: www.
grc.org/programs.aspx?year=2010&prog
ram=highpress
June 27–July 8 XXVth IUGG General
Assembly, Melbourne, Australia.
Web page: www.iugg2011.com
July 4–9 16th International Zeolite
Conference, Sorrento, Italy. Details
forthcoming; web page: www.iza-online.
org/ConfSched.htm
July 10 EMU School: High-Resolution
Electron Microscopy of Minerals,
Nancy, France. Web page: www.univie.
ac.at/Mineralogie/EMU/events.htm
July 10–18 Zeolite ‘10, the 8th
International Conference on the
Occurrence, Properties, and Utilization
of Natural Zeolites, Sofia, Bulgaria. Web
page: http://inza.nmt.edu
J une 2009
CALENDAR
July 22–31 American Crystallographic
Association (ACA) Annual Meeting,
Chicago, IL, USA. Webpage:
www.AmerCrystalAssn.org
July 26–30 73rd Annual Meeting of the
Meteoritical Society, New York, NY
USA. Details: forthcoming. Web page:
www.metsoc2010.org/
August 1–6 Gordon Research
Conference: Organic Geochemistry,
Holderness, NH, USA. Web page: www.
grc.org/programs.
aspx?year=2010&program=orggeo
August 8–13 Gordon Research
Conference: Rock Deformation, Tilton,
NH, USA. Web page: www.grc.org/
programs.aspx?year=2010&program=rockdef
August 8–13 Gordon Research
Conference: Water & Aqueous
Solutions, Holderness, NH, USA. Web
page: www.grc.org/programs.
aspx?year=2010&program=water
August 15–20 Gordon Research
Conference: Biomineralization, New
London, NH, USA. Web page: www.grc.
org/programs.
aspx?year=2010&program=biomin
August 22–26 240th ACS National
Meeting & Exposition, Boston, MA,
USA. Web page: www.acs.org
September 1–4 International
Symposium: Geology of Natural
Systems - Geo Iasi 2010, Iasi, Romania.
Web page: http://geology.uaic.ro/
symposium/index.php?act=inf
September 5–10 11th Congress of the
International Association for
Engineering Geology and the
Environment (IAEG2010), Auckland,
New Zealand. E-mail: [email protected].
nz; web page: www.iaeg2010.com
September 29–October 5 European
Crystallographic Meeting ECM-26 and
EPDIC XII, Darmstadt, Germany.
Webpage: www.lcm3b.uhp-nancy.fr/
ecasig5/Activity.php
September 30–October 9 Society for
Economic Geology 2010 Conference,
Keystone, CO, USA. Web page: www.
seg2010.org/
August 8–13 American Geophysical
Union 2010 Joint Assembly, Iguassu
Falls, Brazil. Web page: www.agu.org/
meetings
August 15–20 Gordon Research
Conference: Solid State Studies in
Ceramics, New London, NH, USA. Web
page: www.grc.org/programs.
aspx?year=2010&program=ceramics
August 22–27 20th General Meeting
of the International Mineralogical
­Association, Budapest, Hungary.
Website: www.univie.ac.at/Mineralogie/
IMA_2010
October 17–21 Materials Science &
Technology 2010 Conference and
Exhibition – MS&T ‘10 combined with
the ACerS 112th Annual Meeting,
Houston, TX, USA. Web page: www.
ceramics.org/meetings/index.aspx
October 31–November 3 Geological
Society of America Annual Meeting,
Denver, CO, USA. E-mail: meetings@
geosociety.org; web page: www.
geosociety.org/meetings/index.htm
November EURISPET: Experimental
Petrology and Rock Deformation,
Zürich, Switzerland. Details: Peter Ulmer,
Swiss Federal Institute of Technology
(ETH) Zürich; e-mail: peter.ulmer@erdw.
ethz.ch; web page: www.eurispet.eu
November 14–18 Third International
Congress on Ceramics, Osaka, Japan.
Web page: www.ceramics.org/meetings/
index.aspx
2011
January 23–28 35th International
Conference and Exposition on
Advanced Ceramics and Composites,
Daytona Beach, FL, USA. Web page:
www.ceramics.org/meetings/index.aspx
A.T.M. Broekmans; e-mail: maarten.
[email protected]; website:
www.icam2011.org
August 2011 74th Annual Meeting of
the Meteoritical Society, Greenwich,
England. Details: Gretchen Benedix,
e-mail: [email protected]
August 22-29 XXII Congress of the
International Union of Crystallography,
Madrid. Web page: www.ecanews.org/
iucrs.php.
March 27–31 241st American
Chemical Society (ACS) National
Meeting & Exposition, Anaheim, CA,
USA. Web page: www.acs.org
August 28–September 1 242nd
American Chemical Society (ACS)
National Meeting & Exposition, Denver,
CO, USA. Web page: www.acs.org
May 19–28 American Crystallographic
Association (ACA) Annual Meeting,
New Orleans, LA, USA. Web page: www.
AmerCrystalAssn.org
September 4–7 7th European Conference
on Mineralogy and Spectroscopy
(ECMS 2011), Potsdam, Germany.
E-mail: [email protected]
May 25–27 Geological Association of
Canada /Mineralogical Association of
Canada Annual Meeting, Ottawa, Canada.
Web page: www.gacmacottawa2011.ca
October 9–12 Geological Society of
America Annual Meeting, Minneapolis
MN, USA. E-mail: meetings@geosociety.
org; web page: www.geosociety.org/
meetings/index.htm
June 20 The Mineralogical Society’s
Annual Meeting: Frontiers in
Environmental Geoscience, University
of Aberystwyth, Wales, UK. Details: N.
Pearce; e-mail: [email protected]; web page:
www.minersoc.org/pages/meetings/
frontiers-2011/frontiers-2011.html
June 26–July 1 Euroclay 2011, Antalya,
Turkey. Web page: www.aipea.org/
downloads/EUROCLAY-2011%20flyer.pdf
June 27–July 8 XXVth IUGG General
Assembly, Melbourne, Australia. E-mail:
[email protected]; website:
www.iugg2011.com
August 2011 10th ICAM International
Congress for Applied Mineralogy,
Strasbourg, France. Details: Maarten
October 16–20 Materials Science &
Technology 2011 Conference and
Exhibition - MS&T ‘10 combined with
the ACerS 113th Annual Meeting,
Columbus, OH, USA. Details forthcoming
The meetings convened by the
societies partici­pating in Elements are
highlighted in yellow. This meetings
calendar was compiled by Andrea
Koziol. To get meeting information
listed, please contact Andrea at
[email protected]
Postdoctoral Position
in Environmental Geochemistry
Behavior of Uranium in
Nanoporous environment
University of Wisconsin – Madison
SEM 2009 ANNUAL MEETING
AND WORKSHOP ON SYNCHROTRON
RADIATION IN MINERALOGY
A postdoctoral position is available in the Department
of Geology and Geophysics, University of Wisconsin–
Madison for experimental research on the role of
nanopores in uranium sorption, desorption, and redox
behaviors. The project seeks to understand the nanopore
effects in both model oxide systems and natural subsurface
sediments. A PhD in geochemistry, environmental
chemistry, or mineralogy is required; laboratory
experience in wet chemistry and manipulation of
microorganisms is highly desirable.
9–11 SEPTEMBER 2009, SALAMANCA, SPAIN_
The meeting of the Mineralogical Society of Spain gathers,
once a year, researchers from Spain and abroad specialized
in the broad fields of mineralogy, petrology and geochemistry.
Like in previous events, the meeting will be preceded by
a topical workshop entitled “Synchrotron Radiation in
Mineralogy.” The meeting and seminar will be held in
Salamanca, Spain, from September 9–11, 2009, and is
coordinated by Mercedes Suárez on behalf of SEM. Do
join us in this historic city and privileged destination of
thousands of international students each year. Please,
check the registration fees and full meeting information
at http://campus.usal.es/~sem09
Please submit by email a cover letter and CV with the
contact information of three potential references to
Prof. Huifang Xu ([email protected]) or
Prof. Eric Roden ([email protected]).
A pplication
Abstracts, elaborated with the template
that can be downloaded from
http://campus.usal.es/~sem09/comunicaciones.html
can be submitted directly to the organizing committee
by sending an e-mail to [email protected]
E lements
will be considered until the position is filled.
Department of Geology and Geophysics
University of Wisconsin-Madison
1215 West Dayton Street, Madison, Wisconsin 53706
608/265-5887 – Fax: 608/262-0693 – www.geology.wisc.edu
199
J une 2009
PARTING SHOTS
The Hope diamond.
Photo by Chip Clark,
copyright Smithsonian Institution
Gaga over Gems
From an academic perspective, gems may be some of the most overvalued and most underappreciated objects on the planet. At least that
is what the authors in this issue want to demonstrate—well, at least
the latter part of the statement. Indeed, gems are where mineralogy
and geology intersect culture most sensitively: by their beauty, they
reach our hearts and humanity. Value derives from emotion as much
as from actual need, so gems are the stuff of love, greed, legends, lust,
envy, and lies. Forget about the science for a minute, and let’s explore
some amazing objects and stories.
Perhaps the most popular and well-known object of any museum is
the Hope diamond. Yes, this is the 45.52-carat, intensely blue, cushioncut diamond housed at the Smithsonian Institution in Washington.
You may like the Mona Lisa better, but the Smithsonian knows that
the Hope is priceless, not just because it is unique, irreplaceable, and
superb. It also has the greatest name recognition of any object in all
of the Smithsonian institutions, so everyone wants to see it. And like
any great diamond, it has a story wound around it, a story that our
colleague Jeff Post is wont to correct, but not too strenuously. Although
there are missing pieces of the history, the stone, named after Henry
Philip Hope (1774–1839), undoubtedly was previously part of the crown
jewels of France. Known as the French Blue or Tavernier Blue, this diamond was acquired in India by Jean-Baptiste Tavernier, brought back from
Golconda, and sold to Louis XIV in 1668. As became fashionable for great
diamonds in the 20th century, a death curse has been attributed to the
Hope, the only true part being that each of its owners died, but only as a
result of being mortal.
Pendant, 4.5 cm in length, set with
Australian opals, chrysoberyl,
sapphires, demantoid garnets,
and pearls in gold. Louis Comfort
Tiffany, 1915–1925. Courtesy of
the A merican M useum of N atural
History; photo by Van Pelt Photographers
drop of holy water touches her enchanted opal, quenching its fire and
the woman’s life. Soon thereafter, opal’s popularity plummeted as a
result of this new symbolism (and coincidentally its relative unavailability at the time). New sources in Australia, plus some promotion by
Queen Victoria, helped revive opal’s popularity. New deposits, such
as in Ethiopia, may help its rising fortunes. The currents of emotion
swirling around gems are colorful and run deep.
Many diamonds are the stuff of legends, some fanciful and others not
so. And diamonds carry more names than all other gems combined.
Cullinan (there are more than nine), Orlov, Regent, Sancy, Koh-i-Noor
(“Mountain of Light”), Kasikçi, Shah Jehan; the list goes on and on. Some
names honor owners, others indicate some relation to the finder, and
still others just reflect their fabulousness. Diamond was the symbol of
virtue and power, and was an alleged poison when powdered and consumed. Recently we have had “blood diamonds,” the destroyer of lives
and societies. Diamonds have also been the stuff of Hollywood fantasy
in movies such as Gentlemen Prefer Blonds and Flawless, and in the annual
parade of beautiful, diamond-bedecked women at the Academy Awards.
At the opposite end of the gem property spectrum is opal. While precious opal is transcendent for its iridescence, it is plagued by fragility
and, once, was the object of a curse that rendered it unpopular and
rejected. In Sir Walter Scott’s Anne of Geierstein, published in 1828,
the heroine’s somewhat sinister grandmother, Hermione, dies when a
E lements
200
George Harlow
American Museum of Natural History
Parting Quote
Anyone who keeps the ability to see beauty
never grows old.
Franz K afka (1893–1924)
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J une 2009
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