Gemstones & Pearls:Gemology
Come to the Circus
With her reliable set of "performers," Gina Latendresse
offers retailers an education in cultured pearl anatomy
Pearls, cultured and the very rare naturals, are compelling gems, sure
to arrest your customers' visual senses. There's something about their velvety
yet shimmering appearance that begs for the human touch.
Once enjoyed only by kings, sheiks or maharajah, pearls became more democratic
after the discovery they could be cultivated in the very mollusks that once
produced them naturally.
Today, almost all pearls are cultured. But there are lot of misconceptions
about a cultured pearl's anatomy, says Gina Latendresse, president of American
Pearl Co., Nashville, TN, which is known for producing superb Tennessee
River cultured freshwater pearls. To answer her own questions about the
anatomy of pearls, Latendresse assembled a formidable collection of natural
and cultured saltwater, freshwater, mabé, blister and keshi pearls,
as well as cross-sections of the various types. She began when she was child
and still adds to the collection to depict advances in pearl culturing and
She affectionately calls the collection her "cultured pearl circus,"
and is happy to demonstrate and explain its many "performers"
to anyone interested in knowing what cultured pearls are about. Her aim
is to educate, which she feels will improve their popularity and sales potential.
Latendresse recently allowed Professional Jewelerto photograph
some of her circus members. Here's how she describes them.
American cultured "coin" pearl
"This cross section of a cultured pearl exhibits
very thick nacre on the shell nucleus. Nacre does not coat evenly: one side
is 2+mm thick, the other is 1+mm.
No enhancements or treatments have been used." [Nacre
refers to the layers of an organic substance a mollusk exudes to coat irritants
that invade its shell. This substance gives pearls their soft appearance
and luster. The thicker the nacre, the better the pearl.]
American cultured pearls
"Notice the color tone differences and beautiful
luster. No enhancements or treatments have been used." [See the For
Your Staff section in this issue for a description of common cultured pearl
Adult and baby snail-type mollusks
"These are possible natural irritants that cause
pearls to form; they are exaggerated sizes. The microscopic larvae of these
mollusks are theorized to be the possible irritant."
American natural pearls
"Note the growth rings in the dissection. This
is similar to tree ring growth. The dark layers could be conchiolin or caused
by dirty water from floods or rain. These pearls formed naturally in the
Tennessee River. No enhancements or treatments have been used." [Conchiolin
is an organic substance that cements calcite and aragonite in pearls and
"Mabé pearls," broken in half
"Notice the paint on the interior of the product.
Also the product is filled with a kind of hard plastic. There's no evidence
of a shell bead [nucleus], only that it's an assembled product. I've dissected
several "mabé" pearls and found there are many ways to
do this. The correct terminology for this product should be "mabé
assembled pearl." The word "cultured" should be included,
Japanese cultured pearl
"All Japanese pearls are bleached, tint-dyed and
enhanced to achieve the beautiful matching colors. The importance of this
dissection is the very thin nacre coating less than 0.5mm thick. In
buying pearls, be aware nacre thickness affects durability and longevity.
Retailers and consumers must be allowed to make an educated choice whether
to buy a product that will become a family heirloom or one that lasts just
a few years. Every cultured pearl has a place in our market no matter
how low the quality because price is a big factor for many buyers.
However, quality must be explained in terms of durability and longevity."
American natural pearls in the shape of wooly
"These pearls have not been carved or enhanced.
Natural pearls are rarely rounded; symmetrical shapes with nice color, luster
and blemish-free surfaces are considered very valuable. Baroque or asymmetrical
pearls, meanwhile, have been used in many different designs such as mermaid's
tails, fish and feathers."
Cultured "corn" and "button"
"This shows the appearance of a possibly natural
pearl. The white pearls are most likely bleached and tint-dyed, but the
pink is naturally colored. The mother mollusk is most likely pink or very
colorful. Various species in the U.S. are naturally pink, purple or lavender,
though many are on the endangered species list." [There's no way to
tell for sure whether a pearl has been bleached. But one tell-tale sign
of tint-dyeing is color concentrations in the nacre near the drill hole.)
All photos by Robert Weldon; pearls courtesy of American Pearl Co.
Copyright © 1998 by Bond Communications.