cultured pearls from vietnam

IN FOCUS: CULTURED PEARLS FROM VIETNAM
CONTENTS
In this issue:
• In Focus: CULTURED PEARLS
FROM VIETNAM
Further topics:
• Pearls at the IGC in Hanoi in
October 2013
• DNA fingerprinting of pearls
• Spondylus pearls
• A Mikimoto “3.5 Momme”
necklace
• Exhibition at the Schwerin
Museum in 2013
Fig. 2. Map of Vietnam. Source: E. Strack, Pearls, 2006, p. 596.
CULTURED PEARLS FROM VIETNAM
A VIETNAMESE LEGEND speaks
of the tears of a princess who had
lost a war against her own husband.
Molluscs collected her tears in the
eastern Sea and transformed them
into colourful pearls. The legend
might refer to the orange pearls of
the marine gastropod Melo melo,
known as baler shell in colloquial
English and as ‘kulon’ in Vietnamese
language. Melo melo occurs along
the coasts of Vietnam in the South
China Sea. Melo pearls are a rarity
and an exclusive luxury item on the
international market (Fig. 1).
The highest price was fetched at
a Christie’s auction in 1999 when
488.000 US dollars were paid in
Hong Kong for an egg-shaped Melo
pearl that measured 23x19.35mm.
Over the centuries, Vietnam has
also produced traditional natural
pearls in bivalve molluscs from the
Fig. 1. Melo pearl, diameter ca. 25 mm.
Private ownership.
Pinctada genus. Both Pinctada maxima, Pinctada margaritifera, Pinctada
chemnitzii (the local equivalent of
the Japanese Pinctada martensii) and
Pteria penguin occur along the entire coast. They are relatively more
abundant in the north where the
Bay of Halong once delivered natural pearls that were equal in importance to those from Hepu and Behai in China, two legendary finding
places not far from the Vietnamese
border. It seems that natural pearls
were nearly exclusively used with
the local nobility but did not necessarily reach the international pearl
market. With the social and political upheavals of the 20th century,
pearl fishing underwent a decline
that has nearly led to a state of nonexistence today. It is still practised,
both in China and Vietnam, to a limited extent only.
MARGARITOLOGIA
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THE PEARL NEWSLETTER BY ELISABETH STRACK
a relatively free economy within a
country that is still officially ruled
by the communist party.
PEARL CULTURE IN
VIETNAM
Fig. 3. Akoya cultured pearls from Vietnam, shown in Las Vegas in 2007 by the Estelle Company.
HISTORY AND PRESENT
SITUATION
The Socialistic Republic of Vietnam stretches over a total length
of 1600 kilometres along the eastern coast of what is geographically
named lower India, bordering on
the South China Sea (Fig. 2). Having
been dominated by China since ancient times, Vietnam gained an independent status only around the
year 1000 with the Li dynasty, ever
since accompanied by constant
struggles for power. Under Napoleon III, France established itself as
a colonial power.
After World War II and the departure of the Japanese who had
occupied the French colonial territory, the French were unable to
hold on to their position during the
so-called First Indo-China war. It
lasted from 1946 till 1954 and ended with the victory of the Viet Minh
under general Vo Nguyen Giap and
the disastrous defeat of the French
during the battle of Dien Bien Phu
in 1954.
Following the Indo-China conference in Geneva in 1954, the coun-
2
try was divided into a northern and
a southern zone. The dispatch of
American military advisors to Saigon in 1962 paved the way for the
second Indo-China war that was to
enter history as the unfortunate
Vietnam War. General Giap was
one of the masterminds behind
the Tet offensive of 1967 that was
to herald the beginning of the end
of the Vietnam war. Giap died on
October 4 in 2013 at the age of 98.
In this context I would like to
mention that the country officially
mourned its legendary general and
national hero on Sunday, October
13, 2013. In the early morning of
this particular Sunday, while we
drove to the airport on the way to
the pearl farm near Nha Thrang
(that is described in more detail
below), we could witness preparations for this historical event in the
streets of Hanoi.
South Vietnam capitulated when
troops from North Vietnam entered in April 1975. The final reunification took part in 1976 under communist leadership. In 1986
followed reforms that allowed for
I saw the first Akoya cultured
pearls from Vietnam at the Las
Vegas show in 2007 where they
were offered by the Estelle Company. The pearls, with a size of up
to 7mm, caught attention by their
creamish colour (suggesting immediately that they had not been subjected to bleaching) and by a certain look that indicated high nacre
thickness to the trained eye (Fig. 3).
A few months later, in October
2007, David Federman wrote in
Modern Jeweler that farmers in Vietnam ‘seem intent on growing pearls
that are throwbacks – in terms of
nacre thickness – to those from the
last years of Japan’s golden age in
the 1950s and 1960s’. Federman
was right. While today nacre thickness with Japanese Akoya cultured
pearls rarely exceeds 0.5 mm, it
may go up to 2 mm with Vietnamese pearls.
The first Vietnamese Akoya cultured pearls in sizes of 2-6 mm
had already been presented at the
great trade fairs in 1999 but they
had apparently not caught too
much attention. In the same year,
a total of about 20 companies had
already set up pearl farms along
the Vietnamese coast, from near
the Chinese border to Phu Quoc
island in the south. Today, production concentrates in three provinces, Quang Ninh, Kien Giang and
Khan Hoa. There seems to be not
more than a handful of companies
involved, but still several hundred
local workers are employed. The
first attempts to produce cultured
pearls in Vietnam go back to the
1960s; they were stopped during
the Vietnam War.
No.1 / 2014
NORTHERN VIETNAM
The second cycle of pearl farming started in the northern Quang
Ninh province that borders on China and the Gulf of Tongking, the
capital is Ha Long city. In 1991, Fujiani Iwaki of the Japanese Ogawa
company opened a pearl farm on
Nhieu Tan island in Halong Bay,
east of Haiphong, the big northern
harbour town. The first pearls were
harvested after only eight months.
Halong Bay, declared a Unesco
world heritage site in 1994, covers
an area of about 1.500 square kilometres, interspersed with nearly
2000 limestone karsts and monolithic islands that rise from the
ocean and are covered with thick
tropical vegetation (Fig. 4). Most of
the few hundred people that make
up the Bay’s population are fishermen and their families who live in
house boat communities. There is
a rich marine life with more than
200 different fish species and
450 species of molluscs, including those of the pearl-producing
Pinctada family.
In October 2013, while I was
in Vietnam for the International
Gemmological Conference in Hanoi, I had the opportunity to visit
a pearl farm near Bo Ton Island
in Halong Bay.
The farm belongs today to the
Vietnamese Ha Long Pearl Joint
Stock Company who took it over in
2005 when the Japanese partner,
Taiheiyo Pearl Company, withdrew.
There are two more pearl farms
in Halong Bay, one is operated by
Spica Pearls and one by Pearls Vietnam Limited, who also owns the
farm near Nha Thrang that is described in more detail below. The
visit was part of a pre-conference
excursion that stood rather under
touristic aspects. Visitors could
however get a good impression of
the principal steps of pearl production. There were demonstrations
of grafting, harvesting and programmes for monitoring molluscs
both before and after nucleus insertion. The farm has a Vietnamese manager and employs several
grafters. Production concentrates
on Akoya cultured pearls of several size ranges, the largest size is
6-6.5 mm. Mother-of-pearl beads
that are used as nuclei are made
from the shells of a local freshwater mussel of the Lamprotula genus
(Fig. 5). The genus is abundant in
East Asia, it occurs also in China
where the shell is reportedly also
used for beads in freshwater cultured pearl production.
A rather large shop on the pontoon is selling cultured pearls of
the farm’s own production under
the brand name Vinapearl, in addition to Akoya cultured pearls
that may not have been produced
locally. The same is definitely true
for those South Sea and Tahitian
cultured pearls that are offered for
Fig. 5. Shell of a Vietnamese freshwater mussel of
the Lamprotula genus, used for making beads on the Bo
Hon pearl farm. Photograph: John Saul.
sale on the farm, complemented
by a great variety of Chinese freshwater cultured pearls. Some necklaces are wrongly labelled as Akoya
pearls.The shop also offered a variety of small gift items made from
shell, including fancy cultured blister pearls that were still attached to
the shells of Pteria penguin (Fig.6).
CENTRAL VIETNAM
The second farm that I visited is in
Khan Hoa province in central Vietnam, about 60 kilometres north of
Nha Thrang, the province’s capital.
The area is a touristic centre with
long beaches and many tiny islands
and coral reefs along the coast.
Flight time from Hanoi is about two
hours, and the journey by car from
the airport to the pearl farm takes
about another hour.
Fig .4. Bo Hon pearl farm near Bo Hon Island. In the foreground, buoys indicate the position of long lines
from where nets and baskets with molluscs are hung into the water. The farm can be seen in the back,
placed on a pontoon. Photograph: Brendan Laurs.
The farm, operated by Pearls
Vietnam Limited, started in the
1990s (the company ’s name was
established in 1997), it is situated in the Van Ninh district of Van
MARGARITOLOGIA
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THE PEARL NEWSLETTER BY ELISABETH STRACK
Phong Bay. A second farm in the
bay belongs to the Saigon Pearl
Company that has its own shop in
Nha Thrang and uses the brand
name Estelle for selling pearls from
Vietnam on the international market (see Fig. 3).
Pearls Vietnam Limited has
a close association, partly family-based, with Oriental Pearl (Bangkok) Ltd. and Baggins of Los Angeles. The latter is now the main
American company that offers
Akoya pearls from Vietnam. Anil
Maloo, Baggin’s president, worked
himself for some years on the farm
in Van Phong Bay that operates
under the supervision of his uncle
Dev Chodhry, who is president of
Oriental Pearl (Bangkok) Ltd. The
farm is a strictly professional one,
efficiently organised, concentrating
on the production of high-quality
Akoya cultured pearls for the world
market (Fig. 7).
There is no shop and there are
no tourists. The deputy general director and the technical manager
are from Japan (the first one comes
directly from Ise peninsula in Mie
prefecture where his parents had
owned a pearl farm) while the staff,
about 200 employees, are Vietnamese. The farm uses only hatchery-produced baby molluscs (as
most farms do since about 2001)
that come from specially selected
wild local parent stock of Pinctada
chemnitzii. The same species occurs along the coast of southern
China, it is closely related to Pinctada martensii that is used for pearl
culture in Japan.
Spawning takes place about ten
to twelve times per year and each
time about one million spat are
produced, this equals 10 to 12 million per year. Immediately after fertilization of the egg cells, the young
larvae have a size of about 1.4 mm.
After 12 hours, larvae have taken
on a D-shape that bears already a
resemblance to the future shape
of the shell and after 24 hours tiny
bivalve shells have already devel-
4
oped. For the first month, they are
kept in basins with seawater.
the sea and is allowed to survive
naturally.
Random checking under a microscope with a magnification between 40x to 180x helps to control if the larvae feed and stay alive
(Fig. 9). After three to four weeks,
they develop cilia (in which state
they are called veliger larvae) and
begin to swim and attach themselves to special nets with mesh
sizes of about 0.5 mm. About 500
to 1000 shells, after having attained a size of about 1cm, are
kept in one net before they will be
brought out to the sea, albeit to
protected places only.
After about one and a half to two
years, when they have attained a
length of approximately 5 cm, the
shells are ready for grafting. The
farm has its own grafting room
Nets are constantly getting
changed, in order to adapt to the
shells’ growing sizes, although
growth speed diminishes after
the first month and growth rates
are irregular. Constant cleaning is
necessary as the nets get quickly covered with mud, seaweed or
sponges. The cleaning procedure
extends well over the whole period
of pearl cultivation Only the best
baby molluscs are selected every
two to three months for further
care, the rest is thrown back into
Fig. 6. A local Pteria penguin shell with a
fancy cultured blister pearl that grew around a snail.
Bo Hon pearl farm.
with a long row of tables that provides room for grafters on either
side. A total of about 350 to 400
molluscs can be operated on in
one day. The farm has about 20
trained grafters (but only about 15
work regularly) who, having been
trained by the Japanese managers, are highly skillful. Nearly all
of them are young women, recruited from villages in the local area
(Fig. 11). The grafting procedure
Fig. 7. View from the farm of Pearls Vietnam Ltd. towards Van Phong Bay
where long-lines stretch at a distance of about 1.8 km.
No.1 / 2014
follows the known basic principle.
In order to prevent the shells from
closing again, a wooden wedge is
inserted into those molluscs that
are chosen for grafting and that
have been anaesthetised.
Strips of mantle tissue are cut
out of the mantle of selected
shells and are consequently cut
into small squares with a scalpel
(Fig. 12). The squares, dipped into a
red disinfectant liquid, are inserted
into the gonad, then follows the insertion of the bead. The farm also
applies a procedure that in Japanese language is termed ‘komo seibo’, it means that the mantle tissue
comes from the same mollusc that
is being used for the grafting process. The method is expected to
improve both colour and lustre of
a pearl.
The Van Phong farm uses only
high-quality beads that come from
professional bead-processing companies in Japan who import the
raw mother-of-pearl from the United States. This means that beads
are more expensive than those
produced from local fresh-water shells. Bead sizes go from below 2mm to 3.8-4 mm, sometimes
5-6mm beads are used. Pearl sizes go from 2-6 mm but 7 mm and
more is possible. Beside of a light
cream colour, more intensive creamish and greyish hues are being
produced (Fig 13). The main pearl
production consists of small sizes
in the range of 2-3.5 mm.Those
so-called ‘baby Akoyas‘ help to fill
the gap in the demand for small
pearls that Japan had not been
able to maintain for many years.
All molluscs usually remain about
one to one and a half year in the
water; with a growth rate of at least
1mm per year; this results in a
nacre thickness of between 1 and
2 mm. The high growth rate is due
to water temperatures and good
environmental conditions. Yearly
production of the farm amounts to
about 150 kilograms.
KESHI PEARLS AND SOUTH
SEA CULTURED PEARLS
Keshi pearls occur as a bye-product of the culturing process, the
amount of pearls harvested is between 1-1.5 to 2-3 per cent of the
total production. The pearls do not
represent a significant sales item
(Fig. 14). Keshi pearls have also
been harvested as a bye-product
of South Sea cultured pearls that
are produced by Pearls Vietnam
Ltd. in the Koto area, also in Van
Phong Bay, near to the Akoya pearl
farm.
The local Pinctada maxima are
about two years old when they are
used for grafting, growth time for
the pearls is also about two years.
Although several harvests have
taken place and the pearls are obviously of superb quality (Fig. 15),
the farm is apparently not yet successful, due to high mollusc mortalities.
have withdrawn meanwhile. Pearls
Vietnam Limited also used to have
a pearl farm on Phu Quoc island
for Akoya cultured pearls. They
were similar to those shown in Fig.
17 and 18 that originate from the
farms of the Spica Pearl Company, also in Vietnam.Pearls Vietnam
Fig. 8. Worker at the farm’s hatchery
THE SOUTH –
PHU QUOC ISLAND
The south-western province of Kien
Giang includes Phu Quoc Island
that is situated in the Gulf of Thailand at a distance of about 40 kilometres from the Vietnamese coast
but only about 12 kilometres from
the coast of Cambodia. The island,
58 kilometres long, has a population of about 70.000 people. During the French and American occupation, it housed the infamous
Coconut Tree Prison, today a tourist attraction.
In Vietnam, the island is famous
for pepper and high-quality fish
sauce. In late 1996, Fujiani Iwaki
(mentioned above) established a
second farm on Phu Quoc Island
that apparently no longer exists
today. There are still a few pearl
farms of varying sizes on the island’ s west coast, south of the
capital Duong Dong but it seems
that most Japanese companies
Fig. 9. Young larvae under the microscope at the farm’s
own hatchery station. Magnification ca. 100x.
Courtesy: Pearls Vietnam Limited.
Limited no longer produces on Phu
Quoc Island, due to high mortality
rates that led to losses of more
than 40 per cent of mollusc populations. Mollusc mortalities seem
to be a constant threat that is menacing pearl farms all over Vietnam.
The largest farm today is Phu Quoc
Beach Pearl Farm, it belongs to the
Phu Ouoc Beach Pearl Joint Stock
Company, that is managed by the
Long Beach group, originating
from the hotel and resort industry.
Foreign partners are from Japan,
French Polynesia and Thailand.
The government issues licences
to foreigners only under the conMARGARITOLOGIA
5
THE PEARL NEWSLETTER BY ELISABETH STRACK
dition that knowledge is passed on
to the inhabitants of the country.
Production on Phu Quoc Island
concentrates on Akoya cultured
pearls, by using the local Pinctada
chemnitzii. Pinctada maxima is used
to a limited extent for the production of South Sea cultured pearls.
The species occurs locally but it
seems that parent stock has been
imported from Australia, as during
the 1990s at least one farm had
been owned by the Australian Asia
Pacific Company.
namese citizen. With his Hoang Gia
Pearl Company, Tuan had originally worked with a group of French
specialists who left the project. It
seems that the surroundings of
the island are especially suitable
for the larger Pinctada maxima and
Pinctada margaritifera molluscs.
of 400-500 kilograms is probably right but some sources speak
of 700-800 or even of 1000 kilograms. The bulk of the production
goes via Japan to the international
pearl market, only a very small part
is sold in the country. Astonishingly enough, unlike Akoya cultured
Most farms have large showrooms that offer locally produced
pearls, albeit to a limited extent
only. To a much larger extent, they
sell imported Akoya, Tahitian and
South Sea cultured pearls and
even Mabe pearls (composite cultured blister pearls) that are locally
worked into jewellery. The majority
of pearls sold are cheap Chinese
freshwater cultured pearls. There
is no government control for the
origin and quality of pearls.
In this context it is worth mentioning the life story of Ho Phi
Thug, Vietnamese owner of the
Ngoc Hien pearl farm who started
as a diver for natural pearls. His
career indicates that fishing for
natural pearls was still practised
at least as recently as twenty-five
years ago when divers apparently,
working at depths of up to 60 meters, expected about one out of
15.000 shells to yield a pearl. Ho
Phi Thug used to sell his pearls to
a Japanese cultured pearl company
whom he joined in 1990 and which
he bought in 1997.
CON DAO ISLAND
Con Dao is an isolated island in the
South China Sea with a dark history
as a place for prisoners. It belongs
to the South Vietnamese province
of Ba Rja-Vung Tau. Apparently,
white, golden and black South Sea
cultured pearls are produced for
the last ten years in a farm that is
owned by Ho Thanh Tuan, a Viet-
6
Fig. 10. Staff sorting out young molluscs for grafting on the farm’s premises. Fig. 11. A grafter at work
Fig. 12. Stripes of carefully cut out mantle tissue, ready to be cut into small squares.
Tuan is apparently planning to
extend pearl farming to the neighbouring coasts of Cambodia.
THE PEARLS
It is difficult to give exact figures
for the country’ s total production
of cultured pearls. An estimate
pearls from China, those from
Vietnam are not mixed up with the
Japanese production and are not
sold as Japanese pearls. They keep
so-to-say their Vietnamese identity. A distinctive characteristic of
all pearls is that they do not, apart
from polishing, get bleached or
processed in any way. As was mentioned already at the beginning,
No.1 / 2014
the high nacre thickness results in
a natural, creamish colour and in a
special, high-quality lustre.
Vietnam has also seen a few
experiments for producing fancy
pearls. Chi Huynh, born in Vietnam
and owner of the Galatea Compa-
were overgrown with an additional pearly layer that enhanced the
drum pattern. Tuan also made experiments with implanting teeth.
Most farms seem to produce a
certain quantity of so-called Mabe
pearls (composite cultured blister
pearls) by using the locally occur-
FRESHWATER CULTURED
PEARLS
Shops all over the country, and
most often those shops on the
pearl farms, sell huge quantities
of cheap Chinese fresh-water cultured pearls, often claiming that
Fig. 14. Collection of several harvests of Akoya Keshi
cultured pearls. Courtesy: Oriental Pearl (Bangkok) Ltd.
Fig.13. Vietnamese Akoya pearl production includes sizes of 2-7mm and light cream to intensely
creamish and greyish hues. Courtesy: Anil Maloo, Baggins, Los Angeles
ny in San Dimas, California, used
the black-lipped Pinctada margaritifera in order to grow small quantities of black cultured pearls in central Vietnam, by implanting beads
of amethyst, citrin or imitation turquoise. The finished pearls were
later carved with floral patterns
that incorporated the colourful
stone beads (Fig. 19). Galatea has
meanwhile become a brand name
for artistic pearl jewellery. While
the pearls are now being produced
in French Polynesia, jewellery manufacturing still takes place in central Vietnam.
Ho Thanh Tuan, already mentioned above with regard to Con
Dao Island, invented another type
of fancy pearls. He had fully grown
pearls engraved with the decorative pattern of the bronze drum,
a Vietnamese cultural icon. The
pearls got implanted again and
ing Pteria penguin. The species,
belonging to the same family as
the Pinctada genus, is also used
for cultivating Mabe pearls on
the neighbouring Chinese island
of Hainan and on the Japanese
Ryukyu Islands. In fact, in Japanese,
the mollusc’s name is ‘mabé’.
Most Vietnamese pearl farms
sell the empty shells to button
companies or local workshops
that make, in pursuing an old Chinese tradition, inlays for furniture.
Pearls of reject quality are used for
powder that is locally worked into
medicine and cosmetics. The molluscs’ inner soft bodies, of which
only the adductor muscle is edible,
are given to the farm workers.
Fig. 15. Both white and golden South Sea cultured
pearls are produced at the farm in Van Phong Bay. Sizes
of the pearls shown are about 10-12mm. Courtesy:
Oriental Pearl (Bangkok) Ltd.
they are of Vietnamese origin. It
seems that Vietnam has presently
no regular production of freshwater cultured pearls but a few pilot
projects seem to be going on in the
northern lakes. Natural fresh-water pearls from the lakes and rivers of northern Vietnam have been
known for centuries. Vietnam has
a similarly large number and iden-
Fig. 16. A selection of South Sea Keshi cultured pearls
from the same farm as the pearls shown in Fig. 15.
MARGARITOLOGIA
7
THE PEARL NEWSLETTER BY ELISABETH STRACK
from the left: Fig. 17 and Fig. 18 show Akoya cultured pearls of exceptional greyish-blue colours and sizes of up to 12mm and beyond. Courtesy: Eliko Pearls, New York.
Fig. 19. Black cultured pearl with a bead of imitation turquoise, produced with the black-lipped Pinctada margaritifera in Vietnam. Courtesy: Galatea
tical species of freshwater mussels than China. Hyriopsis cumingii,
most often used for pearl culture
in China, is one of those species.
In the early 1990s, a pearl farm
existed in Hanoi’s West Lake that
produced about 8000 bead-nucleated pearls in 1993. They did not
make an official appearance on the
western market but were more or
less silently exported both to Asian
countries and the Persian Gulf. It
seems that both Cristaria plicata
and Anodonta yourdyii, a local subspecies of Anodonta woodiana, the
common pond mussel, were used.
Grafters inserted nuclei that were
made of the thick shells of a local
freshwater mussel of the Lamprotula genus. It is endemic in northern
Vietnam and is also used by some
Akoya pearl farms in the country,
as was already mentioned above.
The pearl farm ceased to exist in
early 1996, when it had to give way
to an exclusive sport club.
OUTLOOK
A number of factors speak in favour of pearl farming in Vietnam.
Water conditions are good and
there is still nearly no pollution.
General costs and labour costs are
still low in comparison with Japan.
The local staff is keen to learn and
works in a highly disciplined way.
Yet, it seems that the promising
outlook of seven to eight years ago
cannot be fulfilled and that many
Japanese companies have withdrawn since. It was an outlook that
saw Vietnam going ahead of Japan
as a producer of Akoya cultured
pearls of higher qualities and better prices. Concerning South Sea
cultured pearls, it seems that not
one farm, after initial good harvests, has so far been successful in
the long run.
Bibliography
Bosshart, G. et al., 1993, Freshwater pearl
cultivation in Vietnam. Journal of Gemmology, 23, 6, 326-332.
Chodhry, Dev, 2013, Personal Communication. Oriental Pearls (Bangkokg) Ltd.
Federman, D., 2007, Vietnamese Akoya
Farms?, Modern Jeweler, October 2007.
Lhong Thu Huong, 2013, VN Pearls have the
world as their oyster. Viet Nam News, August
18, 2013.
Strack, E., 2006, Pearls, Rühle-Diebener-Verlag, 2006, 707p.
Various personal communications.
Photographs
All photographs, if not otherwise mentioned, are by E.Strack.
Acknowledgements
Acknowledgements go to Anil Maloo and to
Dev Chodhry of Oriental Pearls Bangkok)
Ltd., for making possible the visit to the
pearl farm in Van Phong Bay and for generously providing information.
PEARL TOPICS AT THE INTERNATIONAL GEMMOGICAL
CONFERENCE IN HANOI, 12-16 OCTOBER 2013
EIGHT LECTURES WERE devoted
to pearl topics.
Shigeru Akamatsu of Mikimoto
and the Central Gem Laboratory in
Tokyo spoke of the Akoya cultured
pearl situation in Japan. He sees it,
similar to the last years, still loaded
with problems as low quality molluscs, low quality mother-of-pearl
8
beads and cheap labour all add
to a decline of pearl quality. This
problem is counterbalanced but
not solved by ever more sophisticated types of ‘processing’, treatments that improve the outward
appearance of pearls only. Moreover, Akoya mortality rates continue
to be high due to environmental
problems.
Akamatsu presented ‘technique
intensive pearl culturing’ as a method that could save the Japanese
cultured pearl industry. It would
aim at the production of small
amounts of high-quality pearls. It
seems that the Mikimoto company,
120 years after its founder harvested the first cultured blister pearl in
1893, is leading the way again. The
No.1 / 2014
company started pearl culturing at
Aino-Shima in Fukuoka prefecture
on Kyushu Island in southern Japan.
The new method pays special attention to natural resources. Only
naturally grown Akoya spat from
the area is used. All waste material
from the pearl farm (mollusc droppings and waste from shell cleaning) is disposed of on land in order
to allow for the self-purification
ability of the sea. Growth time for
pearls is two years again, resulting
in high nacre thickness and other
high quality factors.
The farm environment (water
temperatures, salinity, oxygen demand and the amount of chlorophyll) are monitored by scientists,
accompanied by constant research
in order to be able to guard against
or take early counter-measures
against diseases and other imponderables.
Terrence S. Coldham of the
Gemmological Association of Australia spoke of natural pearls within
freshly opened Pinctada maculata
from what he calls the Tongareva
Atoll (otherwise known as Penryhn
island) in the Cook Islands. Pinctada maculata is the smallest species
of the Pinctada genus; it is endemic on the Cook Islands where it is
locally known as Pipi. Coldham,
while staying on the remote atoll,
was able to watch the harvesting
of about six hundred Pipi shells.
About a dozen contained pearls,
totalling to about 40 pearls.
The largest pearl was 6.50 mm
in diameter. Shapes were mostly round and light to dark golden
colours dominated. Only about
three pearls were of a dark colour.
One photograph showed a freshly
opened shell with three pearls situated inbetween the internal and
external mantle epithelium that
looks transparent. Both the number and size of the pearls (the largest pearl had about 5 mm) evoke
astonishment, as the length of the
mollusc’s shell is only about 6 cm.
A report on ‘Galatea’ pearls, presented by Professor Henry Hänni
for the authors Laurent E. Cartier, Michael S. Krzemnicki and
John Rere, described the use of
gemstone beads for producing cultured pearls that are subsequently
artistically carved to display both
the colourful gemstone nucleus
and the nacreous layers.
Pearls of this type have been
produced by the American Galatea Company of San Dimas, California, since 2007. The owner of
the company, Chi Huynh, is born in
Vietnam where the first pearls were
produced (see above, p.7) with the
black-lipped Pinctada margaritifera. This has changed meanwhile,
at present all pearls are produced
at a farm in the Gambier Islands of
French Polynesia, using the local
black-lipped Pinctada margaritifera
cumingii. Jewellery workshops have
remained in Vietnam.
By collecting wild spat and nursing it until the young molluscs are
about three years old, the farm
follows the proceedings that are
common in French Polynesia. For
the first operation, a plastic bead
is used. The resulting pearls are
harvested after about six months.
They are not for sale but the purpose behind is to create a larger
pearl sack for inserting the gemstone beads. 10 to 12 months later,
the new pearls are being harvested. Retention rate is apparently
high with these second-generation
pearls while the molluscs tend to
reject gemstone beads when they
are implanted right from the beginning. Nacre thickness falls within the required 0.8 mm minimum
limit set by the Tahitian authorities.
A production of 100.000 pearls is
expected for 2014.
Stefanos Karampelas of the
Gübelin Laboratory (co-authors
are Enrique Arizmendi, Douglas
McLaurin, Manuel Nava, Pierre
Hardy and Lore Kiefert) spoke on
the current situation of pearl cultivation at Guaymas in Mexico. At
present, about twelve people work
for the Perlas del Mar de Cortez
Company. Wild adult molluscs cannot be used for the cultivation process as their fishing is still banned,
therefore wild spat is collected
and reared in the waters of the
farm. Only Pteria sterna molluscs
are used, about 250.000 young
molluscs are produced every year.
The cultivation period lasts from
18 to 20 months, and an average
of 4.000 pearls of saleable quality
are harvested per year, including
about 300 keshi pearls. The diameter of the smallest beaded pearls
is about 8 mm and the average size
is 9 mm, while it was below 9 mm
in 2004.
A diameter of above 12 mm is
rare. 14 mm is the maximum size.
Only about one per cent of all
pearls are nearly round and so far,
only about nine necklaces were
produced from harvests over the
last 14 years.
All pearls from Pteria sterna
show a strong red fluorescence
under long wave ultra violet light
(366nm). The authors applied
different methods to study 10
pearls in detail, applying both Raman and UV-Visible-NearIR spectroscopy and X-radiography and
examining the pearls with a standard gemmological microscope.
Steve Kennedy of The Gem &
Pearl Laboratory in London gave a
report on his testings of the Pearl
of Asia, one of the largest and most
famous pearls.The report of which
no details are to be published due
to the wishes of the present owner
of the pearl, included details of the
pearl’s history and conjecture on
its origin.
A contribution by Kenneth Scarratt of GIA Thailand dealt with additional data on natural and culMARGARITOLOGIA
9
THE PEARL NEWSLETTER BY ELISABETH STRACK
tured pearls from Pinctada maxima
in Australia. A selection of pearls
was studied: natural pearls from
wild shell from the 80 mile beach,
natural pearls from shells from
the 80 mile beach that had been
grafted for cultured pearl production, natural pearls from grafted
hatchery-produced shells and both
cultured pearls with and without
a bead, grown both in shells collected from the wild and in hatchery-produced shells.
All pearls were photographed
while still in their pearl sacks in order to register their position within
the molluscs. They were then examined by using Real-Time microradiography and X-ray computerized microtomography as well as
Laser Ablative Inductively Coupled
Plasma-Mass Spectrometry.
Pearls located in the area of
the mantle closest to the gills and
the widest point of the adductor muscle revealed characteristic
structures of natural pearls. Beadcultured pearls from the gonad revealed clear images of the beads.
Non-beaded cultured pearls from
the gonad revealed two distinct
growth structures that are now
associated with saltwater keshi cultured pearls. Trace element chem-
istry confirmed that the colour and
chemistry of the bead-cultured
pearls are linked with the implanted mantle tissue as opposed to the
mantle tissue of the host.
Sutas Singbamroong (co-author is Nazar Ahmed) of the Dubai
Central Laboratory explained how
a digital SLR camera can be applied
to photograph x-ray luminescence
of pearls. Chinese freshwater cultured pearls display, caused by the
presence of manganese, a distinct
greenish-yellow luminescence. Dull
surface areas may show an orange
luminescence.
The vast majority of beaded
salt-water cultured pearls reveal,
due to the fresh-water origin of
the mother-of-pearl beads, variable luminescence reactions. Visibility of those reactions depends
on nacre thickness; a high nacre
thickness may mask visibility. Naturally dark-coloured pearls or dyed
pearls may inhibit luminescence
reactions.
ural and non-beaded salt-water
cultured pearls. They can be difficult to interpret as their formation
depends on different factors. 10
salt-water cultured pearls without
a bead from Pinctada maxima and
10 salt-water natural pearls from
Pinctada radiata were studied by
using X-radiography and/or microcomputer tomography. Some
of the samples in sizes from 3 to
8 mm, going from near round to
baroque shapes, were cut in half.
Cavities observed in natural
pearls are darker in colour and more
irregular in shape, and they align to
a certain extent with the external
shape of the pearls. Cavities visible
in samples of cultured pearls have
a more distinct outline, are more
linear, and may show a tail, they
are not flowing with the external
shape of the pearl.
Bibliography
IGC 2013 Vietnam, Abstract Proceedings,
33rd International Gemmological Conference, October 2013, Hanoi, Vietnam.
Abeer Tawfeeq Al-Alawi of the
Gem & Pearl Testing Laboratory
of Bahrain (co-authors are Stefanos Karampelas and Osama
Taqi) compared the appearance
of ‘cavities’ on x-ray images of nat-
DNA FINGERPRINTING OF PEARLS FOR ORIGIN
DETERMINATION
THE PUBLICATION of October 2013
in PLOS ONE presented for the first
time truly new research results on
pearls. One might even speak of
exciting news. It is the result of the
cooperation between the SSEF in
Basel (and its former director Henry A. Hänni), the Swiss Federal Institute of Technology in Zürich and
institutes at the Universities of Basel and Lausanne.
The authors report on the first
successful extraction of oyster
10
DNA from a pearl. It was used to
identify the source oyster species
for the three major pearl-producing oyster species Pinctada margaritifera, P. maxima and P. radiata.
18 pearls of unknown origin
were examined. A micro-drilling
technique was developed to obtain
small amount of DNA while maintaining the commercial value of
the pearls. The DNA fingerprinting
method could be used in the future
to document the source of historic
pearls and to provide transparency
as to the origin of pearls.
(Explanatory note: The word ‘oyster’ is used in
this short review with regard to the authors’
use of the word within the original text).
Bibliography
Joana B. Meyer, Laurent E Cartier, Eric A.
Pinto-Figueroa, Michael S. Krzemnicki, Henry A. Hänni, Brucecc A. McDonald, 2013,
DNA Fingerprinting of Pearls to Determine
Their Origins, PLOS ONE, Vol. 8, Issue 10,
October 2013, e75606. Online available.
No.1 / 2014
SPONDYLUS PEARLS
WHEN, IN PREPARATION of my
pearl book in the late 1990s, I was
writing on pearls from ‘other marine bivalve molluscs’ (meaning
other genera than Pinctada and
Pteria), it was rather for the sake of
completeness and for referring to
all those species that do occasionally produce pearls.
in the past. Spondylus americanus,
the so-called American spiny oyster, has a pinkish-white shell and
occurs on the Atlantic coast from
the south-eastern United States
down to Brazil. Spondylus princeps
occurs on the American Pacific
coast as far down as Panama and
also in the Gulf of California.
iterranean Sea and along the Atlantic coast of northwestern Africa,
was reported as having produced
white, light green and pinkish
pearls. While pearls from Spondylus have so far only been reported
on and were difficult to trace and
to actually see, a few pearls were
presented in Tucson 2013. The
These pearls are extremely rare
but until not more than five years
ago they represented rarities in
the sense of oddities or curiosities, objects that one would have
expected to find in the Wunderkammer collections of Renaissance
potentates and their followers. The
pearls were not seen as rarities in
the sense of costly jewellery objects. In fact, they were hardly ever
to be seen at all.
Interestingly enough, the natural
pearl boom that started about ten
years ago on an international level
(and on a small international level
only) brought about a new focus. It
seems that all of a sudden the pearl
market does not only notice those
‘other’ pearls but assigns a high
monetary value to them, treating
them as equals to traditional natural pearls and largely ignoring their
often obvious lack of beauty.
Pearls from the genus Spondylus
L., 1758, belonging to the Spondylidae family, can be seen as a good
example. The rather domed shells
of the bivalves show large spines
on their outside which account for
the names ‘thorny oyster’ or ‘spiny
oyster’ in colloquial language. The
spines attract algae and sponges that provide an almost perfect
camouflage for the shells. The
more than 25 species in the family are difficult to distinguish from
each other, and most reach a
length of more than 10 cm.
White and pale pink pearls have
been reported from both Spondylus
americanus and Spondylus princeps
Fig. 1. A ‘spiny oyster’ of the Spondylus genus.
Fig. 2. Red Shell’ spiny oysters and Indian jewellery offered for sale in Tucson. Courtesy: Red Shell Company.
Fig. 3 and 4 show ‘red shell’ jewellery, made from the shells of Spondylus princeps Courtesy: Red Shell Company.
The shells of Spondylus princeps
may show different colours. Those
with white shells live in a depth of
18-30 metres and those with a red
shell live in deeper waters of about
30-50 metres. Fig. 2 shows a selection of ‘spiny oysters’ that are
usually offered for sale in Tucson.
Following an Indian tradition, the
red shells are still today worked
into jewellery, both into individual
cabochons and necklaces that are
quite popular in the United States
(Fig. 3 and Fig. 4).
In Costa Rica, Spondylus calcifer, living in shalllow waters, has
become known for occasionally
also producing pearls. Spondylus
gaederopus, occurring in the Med-
pearls had allegedly been bought
directly from the fishermen in Baja
California in Mexico.
Fig. 5 shows six pearls of round
to off-round and egg-like shapes,
Fig. 5. six pearls from Spondylus princeps,
Baja California. Length of largest pearl ca. 14mm.
Courtesy: E. Rodriguez.
MARGARITOLOGIA
11
THE PEARL NEWSLETTER BY ELISABETH STRACK
with one pear shape, the length of
which is 14 mm. Two pearls have
off-white colours, mottled with
light brown while four pearls have
a dull greyish-green colour with
brownish and greenish circles. Lustre is dull, with the exception of the
smaller off-white pearl that has a
porcelain-like lustre.
Fig. 6 shows a nearly perfectly
round, white pearl, ca. 12 mm, with
a dull to faintly porcelain-like lus-
tre. It resembles a Tridacna pearl,
showing a weak, difficult to recognize flame structure.
The pearls were not examined in
detail so far and they most probably do not have outer nacreous
layers (layers of aragonite platelets
in a brick-type arrangement) that
make up the structure of pearls
from the Pinctada genus.
All photographs are by E. Strack
Fig. 6. Pearl from Spondylus princeps, Baja California.
Diameter ca. 12mm. Courtesy: E. Rodriguez
A MIKIMOTO ‘3.5 MOMME’ GRADUATE
ONLY ABOUT 100 PEARL FARMS
in Japan had survived World War
II and in the early 1950s Mikimoto was the only large producer.
His emphasis was on pearl quality and the women who worked
in the sorting rooms did not select
more than six necklaces per day.
In those years, nacre thickness was
about 1mm; it equalled the standard of before World War II.
While a nacre thickness of between 0.6 mm and 1mm was consid-
ered normal until into the 1970s, it
has since gone down tremendously. In the 1950s, necklaces were
almost all still graded, in a way imitating natural pearl necklaces. The
pearls’ diameters ranged from 3 to
5mm, the centre pearl was 7 mm.
The trade called these necklaces
‘3.5 momme graduates’ as they
usually had a weight of 3.5 momme.
1 Momme equals 3.75 grams. In
1946, the High Commander of the
Allied Forces in Japan had initially
Fig. 2. The Mikimoto logo from the original box.
issued a number of rules that prohibited the sale of pearls within the
country and allowed only sales to
the Central Office of the American
supplies. All pearls were sent to
the United States or they were sold
within Japan to the families of the
American military forces. Nearly all
sales continued to go to the United
States, after exports were allowed
again in 1948. It was later thought
that the roots for the popularity of
Japanese cultured pearls in America go back to this time.
Fig. 1 shows an early Mikimoto
necklace. It is still in the possession
of an American lady whose fiancé
and later husband had bought it in
1955 while he stayed with the military in Japan. The necklace is still
kept in its original box.
Bibliography
Strack, E., 2006, Pearls, Rühle-Diebener-Verlag, 2006, 707p.
Fig.1. An early ‘3.5 momme graduate‘ necklace, bought in 1955 in Japan. Courtesy: Marian Havlik.
12
Acknowledgements
Acknowledgements go to Marian Havlik
No.1 / 2014
SCHIMMERN AUS DER TIEFE: MUSCHELN – PERLEN – NAUTILUS
EXHIBITION AT THE STAATLICHES MUSEUM SCHWERIN IN
MECKLENBURG, GERMANY, JUNE 14 – SEPTEMBER 15, 2013
SHELLS AND PEARLS WERE an
integral part of early princely collections that included both objects
of natural origin and man-made
artefacts. Influenced by the great
discoveries of the 15th to 17th
centuries, those collections endeavoured to explain the world.
Moreover they served to enhance
their owners’ prestige and position
in the world.
The exhibition of last summer
at Schwerin, capital of the Grand
Duchy of Mecklenburg-Schwerin till
1918, allowed the State Museum to
focus on objects that were collected by the princely family. Several
topics were addressed, beginning
with the use of shell in both representational and liturgical objects.
The fanciful use of mother-of-pearl
was for example demonstrated by
a selection of colourful fans from
the 18th and 19th century.
A large part of the exhibition was
dedicated to pearls. However, the
presentation of princely pearl jewellery was by necessity confined to
painted portraits of the duchesses and princesses of (mainly) the
Mecklenburg dynasty as the original jewellery is no longer available.
A range of portraits from the
16th to 19th centuries conveyed
to the viewer an impression of
both the beauty and importance of
pearls as objects of high value and
symbols of power. Luckily enough,
drawings of pearl jewellery, done
in the middle of the 19th century,
have survived, as have black-andwhite photographs made in 1907
and 1925/1935. Small pieces of
sentimental jewellery from the late
18th and the 19th century, later
acquisitions of the museum from
private individuals, were shown to
demonstrate the purely decorative
use of small pearls.
Further aspects included the use
of shells in the goldsmith’s art, for
example by working Nautilus and
Turban shells into fanciful goblets.
Moreover, shells became much
sought-after objects for being represented in above all still life paint-
ings. It was a pleasant surprise to
see in this context a painting by
Sigmar Polke of 1988 that shows
a Nautilus goblet in transparent
yellow acrylic paint in front of a red
and white background. The painter claims that he was inspired by a
photograph in an art book.
In the context of 20th century
art, the exhibition paid homage to
the photographer Alfred Ehrhardt
by showing his series of black-and
white photographs of shells that
he made in the 1940s. They go far
beyond the reproduction of natural objects and provide an aesthetic pleasure to the viewer. A possible influence by the 19th century
scholar Ernst Haeckel’s Kunstformen der Natur was traced.
Exhibition catalogue by Michael
Imhof-Verlag. 2013, 367 pages,
with numerous high-quality photographs. D-36100 Petersberg.
IMPRESSUM
margaritologia – THE PEARL NEWSLETTER– is published by
Elisabeth Strack
Gemmologisches Institut Hamburg
Poststraße 33
Business Center
20354 Hamburg
Tel. 0049-40-352011
Fax. 0049-40-343419
E-Mail: [email protected]
www.strack-gih.de
ISSN No. 2199-7845 English edition
margaritologia is published since 2014 in both English and German languages.
MARGARITOLOGIA
13