The Petoskey Stone - Oakland County Earth Science Club

The Petoskey Stone
page 4
March
"January"
"February"
""
"April"County Earth Science Club
Oakland
The Petoskey Stone
January 2011
www.OCESC.com
Geological Timescale gets new Period
Club Meeting
January 5th
7:30
Board Members
meet at 6:15
If January comes, can April
be far behind?
Not with preparations for the April
auction !
We're looking for members, who
can help us sort, wrap, price or
organize specimens for the April
auction. We will meet on Friday
afternoons at 1:00, beginning January
21. If you haven't done this before,
come on by. It's a good way to learn
about rocks and minerals.
-- Katherine Van Hoy
DUES DUES DUES
YES, it is that time of the year when
yearly dues are due. The fee is
$20.00, with no extra charges. I will
be collecting them at the January
meeting so please don't make me run
after you. I'm getting too old. See
you, JANUARY 5th.
Eleanor
SILVER CLASS Delayed
Silver Class was to begin soon, but
Eleanor Snyder has unfortunately
broken her ankle, and must heal
before she can teach the class. Our
best wishes for a fast recovery
Eleanor!
--Laura Sheffer
(Editor’s note: The Ediacaran Period status
as an official geological period was ratified
in 2004 by the International Union of
Geological Sciences (IUGS), making it the
first new geological period declared in 120
years. This extract’s complete 2004 article
link can be found at www.amfed.org, under
“In the News” links.)
The Ediacaran Period covers some 50
million years of ancient time on our planet
from 600 million years ago to about 542
million years ago.
It officially becomes part of the
Neoproterozoic, when multi-celled life
forms started to take hold on Earth.
However, Russian geologists are unhappy
their own title - the Vendian - which was
coined in 1952, was not chosen. The
decision was taken after a fifteen-year long
period of consideration by expert
geologists.
"There's always been a recognition that the
last part of the Precambrian is a special
time before the first shelled animals, when
there are these weird, mesh-like creatures
of uncertain affinity," Professor Jim Ogg,
secretary-general of the International
Commission on Stratigraphy (ICS), told
BBC News Online. “Now it’s part of the
official timescale."
The Petoskey Stone
Upcoming Events (events can be found at www.rockngem.com or www.amfed.org/mwf/Calendar/) For
detailed information, please visit individual club’s website.
OCES Club members Silversmith class- delayed until further notice. Eleanor will make an announcement at
the January meeting.
2011 Refreshments
Jan.
Feb.
Phyllis Keene, Lynnette West, Kathy --Mar.
April
May
June Banquet-Potluck
Sept. K. Van Hoy, E. Snyder, D. &L. Whitehead
Oct.
Rose Woerner, Chris Shull
Nov. Paulette Barterian, Linda Whitehead
Dec. Club Banquet-everyone bring a dish
2011 Programs
Jan.
Chuck Miller, ‘The Rock Cycle’
Feb.
Mar.
April
Silent Auction
May
June -Sept. --How the Earth Formed- Great Lakes
Oct. – Alps – How the Earth Was Formed
Nov. Club Member Swap/Sale
Dec.
--Banquet
(each month needs two volunteers –please consider)
--Betty Cockerham, Program Chair
***** January Birthdays *****
1
JACKIE MIDTGARD
6
GEORGE MATYAS
10
JANE GUNTERMAN
10
JIM RIVES
12
ROSE SEIBERT
26
LAURIE WILKINS
“People find life entirely too time-consuming.”
Stanislaw J. Lec, Unkempt Thoughts
Photo: Lt. Elizabeth Crapo, NOAA Corps
Interesting Sites to Visit:
The USGS (United States Geological Survey) has a number of educational and interesting materials at their
website. One in particular, http://geomaps.wr.usgs.gov/parks/rxmin/, has a nice introduction to general geology.
Charts, color pictures, and links to more in-depth information is available.
The Vug website, http://www.the-vug.com/ is a commercial site, but has a lot of information, pictures, show
info, etc.
National Geographic Magazine’s site always has interesting items, especially on the science page:
http://science.nationalgeographic.com/science/
The Petoskey Stone
OCES BOARD MEETING DECEMBER 8, 2010: No Board Meeting was held.
OCES GENERAL MEMBERSHIP MEETING, DECEMBER 8, 2010: The meeting started with grace
being said and followed by a delicious buffet dinner provided by members with the club providing chicken and
ham. A BIG THANK YOU to Nancy Pfauth and her committee for all of their hard work! After the dinner, the
meeting was called to order at 7:45 pm by President Dan Woerner. Both the Treasurer’s and the Minutes were
approved. Leon Pearson stated that since the By-Laws changes had already been read twice and published
once, they were ready to be approved. Motion to approve By-Law changes was made and approved by
membership. Cathy Roller gave the Oath of Office to the new Board members: Bob Albertson, Nancy
Mathura, Nancy Pfauth, Tom Pierson and Roberta Thomas. Their terms will run for three years. Life
Memberships were given to Kathryn Van Hoy, Eleanor Snyder, Barb and Tom Pierson and Phyllis Keene.
CONGRATULATIONS! Tony West will be going out to Oregon for a field trip and asks that interested
members contact him. Points of interest include Hampton Butte and Davis Creek for obsidian and petrified
wood. Linda and Dave Whitehead passed through Henderson, North Carolina and said that the museum was
worth the trip. Eleanor has name tags for all of our new members. Rose Woerner announced that gem trees
will be the kid’s project in January and passed around a sample tree. Jim and Pat Rives thanked everyone again
for the great food. The meeting was adjourned at 8:10 pm. Respectfully submitted, Chris Shull, Secretary.
HOW TO OPEN A GEODE ( a continuation of the Junior Activities article on the next page)
There are 3 main ways to open a geode.
1. Find someone with a “geode-cracker”.
2. Cut it in half with a diamond or masonary saw.
3. Strike it with a hammer and chisel - the most common way. But don’t just swing wildly. Small geodes will
crush easily.
a. If the selected geode feels light for its size, it probably has an inside pocket which may be lined with
crystals.
b. Wear safety glasses and gloves.
c. If the geode is big enough, use a chisel to gently score all along the circumference.
d. Then put the geode in an old sock and put the chisel in one of the score marks and tap gently in order to not
crush the geode.
e. If the geode does not break, tap harder. Use the minimum of force necessary to open it.
f. The sock will keep the pieces from flying into eyes or getting lost.
g. If the geode is not big enough to score with a chisel, put the geode in an old sock and gently tap it. Again,
tap harder if it does not break, but use as little force as possible in order to not destroy the crystals that may
be inside
h. Be aware that the geode may be totally filled in or simply a solid concretion. Not all apparent geodes will
have desirable things inside.
Sources:
GEODES-Nature’s Treasures, by Brad L Cross and June Culp Zeitner, Gem Guide Book Co., Baldwin Park, CA.
2006.
1001 Questions Answered About the Mineral Kingdom, by Richard M Pearl, Grosset & Dunlap, New York NY 1959.
JUNIOR ACTIVITES by Michele Yamanaka, interim MWF Junior Activities Chairman
Written for the November 2010 Strata Data and the December 2010 MWF News.
HIDDEN BEAUTY: A Look Inside GEODES
WHAT IS A GEODE?
The word geode comes from the Greek word geoides, which means “earth-like”. Geodes are earth-shaped (as in
the planet Earth, therefore somewhat round) natural, organic objects which are or have been hollow. Usually it
has an outer shell of chalcedony, which is in the quartz family. The interior of the object may be lined with
crystals, most often quartz, which point toward the center. There may be secondary mineral growth. It should
show concentric inward growth and may even be completely filled in. Then it is called a nodule.
HOW DO GEODES FORM?
Scientists are still investigating geodes and there are different ideas about where and how they form. The
information
shared here is based on the recently published book, GEODES-Nature’s Treasures, by Brad L Cross and June
Culp Zeitner, Gem Guide Book Co., Baldwin Park, CA. 2006.
Geodes form in sedimentary rock and in igneous rock. Sedimentary geodes are less round than igneous geodes
and contain more calcium carbonate. Some of the possible origins of geodes are:
 gas bubbles in volcanic rock in which silica-rich solutions fill in the bubble area
 expansion of fossil shell and replacement of calcite by silica
 a concretion formed by anhydrite or calcite that is replaced by silica and re-crystallization of calcite
 silica gel filling in a cavity left in sediment by marine life such as sponges or clams
There is no “one” way that geodes seem to have formed. They all have in common that:
1. the exterior surface of the geode is harder and tougher than the rock in which it is found;
2. layers grow inward toward a central area that started as a cavity.
Some geodes are fossil-shaped; some are quartz paramorphs after coral or shells. They can be tiny or several
feet across. The outside and inside can be any color of the rainbow. The crystal formations inside can be welldefined crystal shapes, bubbly, grape-like, or stalagtitic. Many kinds of minerals, such as quartz, calcite, pyrite,
selenite, barite, malachite, fluorite, sulfur, opal and more, can be found inside geodes, including petroleum,
water and gas.
The most exciting thing about geodes is that the outside gives no clue about what is inside. It is an amazing
experience to be the first to see what treasures may be inside!
(see previous page for ‘how to open a geode’ a continuation of this article from the MWF newsletter)
The Petoskey Stone
Lapis Lazuli
Extract of an article from The Living Stones, Nov. 2010, credited to ICA Gem Bureau, Idar-Oberstein
Lapis lazuli is regarded by many people around the world as the stone of friendship and truth. The
blue stone is said to encourage harmony in relationships and help its wearer to be authentic and give his or
her opinion openly.
Lapis lazuli is an opaque rock that mainly consists of diopside and lazurite. It came into being
millions of years ago during the metamorphosis of lime to marble, Uncut, lapis lazuli is mat and of a
deep, dark blue colour, often with golden inclusions and whitish marble veins. The small inclusions with
their golden shimmer, which give the stone the magic of a starry sky, are not of gold as people used to
think, but of pyrites. Their cause is iron. The blue colour comes from the sulphur content of the lazurite
and may range from pure ultramarine to a lighter blue. At between 5 and 6 on the Mohs scale, this stone is
among the less hard gemstones.
The worth of this stone to the world of art is immeasurable, for the ultramarine of the Old Masters
is nothing other than genuine lapis lazuli. Ground up into a powderand stirred up together with binding
agents, the marble-like gemstone can be used to manufacture radiant blue watercolours, tempera or oil
paints. Before the year 1834, when it became possible to produce this colour synthetically, the only
ultramarine available was that valuable substance made from genuine lapis lazuli that shines out at us
from many works of art today. Many pictures of the Madonna, for example, were created using this paint.
6