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Are
all Tahitian pearls black? What’s the difference between
a cultured pearl and a natural pearl? Are freshwater
pearls inferior to saltwater pearls? Are South Sea
pearls really golden?
Good
questions. With all the different pearl colors and types
out there, it can be difficult to know just what you’re
looking at. For those interested in buying pearls, or
for gem enthusiasts who wish to learn more, here are
answers to some of the most commonly asked questions
about pearls.
Are
All Tahitian Pearls Black?
Not
only are Tahitian cultured pearls not exclusively black,
they’re also not grown in Tahiti. Called “black" because
of their exotic dark colors, Tahitian cultured pearls
can also be gray, blue, green and brown. And they’re
grown in the lagoons of small islands that are part of a
group known as
French Polynesia.
Tahiti, the largest island, serves as the group’s center
of commerce, and not as a pearl growing mecca.
Tahitian pearls are cultivated for about two years in
Pinctada margaritifera cumingi, a large mollusk
native to French Polynesia. One of the ways this unique
oyster differs from other species is its interior shell
color, which is dark. This so-called “black lipped"
oyster also has black mantle edges—the “lips" that give
this animal its descriptive name.
Today, the most sought-after Tahitian cultured pearls
are dark green-gray to blue gray with rosé or purple
overtones. Pearl colors are determined by several
factors, including variations in the host oyster, color
variation of the implanted donor mussel tissue, the
number and thickness of nacre layers, and variations in
growing environment such as temperature and water
quality. Tahitians are most often variations of gray,
black, green and blue, but other colors exist.
At an
average size of 8mm-14mm, Tahitian cultured
pearls—especially those specimens that are gem-quality
and round—are very expensive. According to the latest
information from the Gemological Institute of America,
up to 40 percent of implanted black-lipped oysters
produce a gem-quality cultured pearl, but only about 5
percent of the pearls they produce are round. And only
1-2 percent of the entire crop will result in round
cultured pearls of the finest quality. No wonder a
Tahitian pearl strand is so costly! If you want to wear
Tahitian cultured pearls, one way to do so without
breaking the bank is to choose a pendant-style necklace
with a single pearl, pearl stud earrings, a single pearl
ring, or baroque (non-symmetrical) pearls. These designs
are every bit as exotic and a lot more affordable than a
matched strand.
What’s the difference between a cultured pearl and a
natural pearl?
Natural pearls are formed when an irritant, such as a
parasite, makes its way into a pearl-producing animal
such as an oyster or mollusk. To protect itself, the
animal coats the irritant in nacre—a combination of
organic substances that also makes up what we call
mother-of pearl. Over time, the layers of nacre build up
around the intruder and eventually form the organic gem
we all know as the pearl.
Cultured pearls are formed in the same way as natural
pearls, with one big difference: they get their start
not by chance, but deliberately, when man intervenes
with nature. To produce cultured pearls, a skilled
technician, called a nucleator, induces the
pearl-growing process by surgically placing an
irritant—a mother-of-pearl bead and a piece of mantle
tissue, usually—into a mollusk. The animal is then
placed back into the water and monitored, cleaned, etc.
until the pearl is ready to be harvested.
The
Chinese have been culturing freshwater blister pearls
(pearls that grow underneath the mantle on the inside of
the animal’s shell) since the 13th century,
but Kokichi Mikimoto, a Japanese man, is credited with
developing modern pearl culturing techniques. By the
early 1920s, Mikimoto was selling his cultured pearls
worldwide.
Natural pearls can be very beautiful, but due to
overfishing, pollution and other factors, they are a
rare find indeed. Thus, nearly all pearls sold today are
cultured pearls. There are two main types: freshwater
and saltwater. South Sea cultured pearls, Tahitian
cultured pearls and akoya cultured pearls are all types
of saltwater pearls. Cultured pearls of all types can be
found in jewelry stores worldwide.
Are
saltwater pearls better than freshwater pearls?
It
depends on who you ask, but many pearl experts today
agree that freshwater cultured pearls can rival the
beauty of their saltwater cousins. Due to improvements
in culturing techniques, freshwater pearl farmers are
producing beautiful, round, lustrous pearls that are a
vast improvement over the wrinkled, rice-krispie-shaped
gems that typified the freshwater pearl crop of the
not-so-distant past.
Produced mainly in China, freshwater pearls are often
nucleated, or implanted, with mantle tissue only (rather
than a mother-of-pearl bead). Because they do not
contain a starter bead, tissue-nucleated freshwater
pearls are 100% nacre. This gives them a beautiful
luster and a durable surface that won’t easily flake or
peel to reveal the inner bead. By contrast, pearls that
are bead-nucleated and harvested too soon often have
only a thin coating of nacre that will flake or peel.
This is a major problem: Unlike many other gemstones,
pearls cannot be polished back to perfection.
Freshwater cultured pearls come in many beautiful
natural pastel colors including cream, white, yellow,
orange, pink and lavender. (Universally flattering
lavender pearls are very popular right now.) White
pearls are bleached to enhance their natural shine.
Black freshwater cultured pearls are treated with dye or
heat to produce their inky color.
Overall, freshwater pearls are more plentiful than other
pearl types, thus they are generally more affordable.
Are
South Sea pearls really golden?
Yes.
Pearls produced in the aptly named “gold-lipped" oyster
(P. maxima) can be a gorgeous creamy yellow,
referred to as “golden" in the trade. (The silver-lipped
variety of P. maxima produces beautiful silver or
white pearls.) Grown in the
South Seas—which stretch from the southern coast of
Southeast Asia to the northern coast of Australia—these
pearls are grown in one of the biggest oysters used in
pearl culturing. Because they can accept a larger
bead and secrete nacre faster than their smaller
counterparts, these big oysters produce large pearls of
exceptional luster and beauty. South Sea pearls’ thick
coating of nacre gives the gems a wonderful luster, or
glow, that appears to come from deep within the pearl.
The warm waters, abundant food supply and low pollution
levels of the South Seas also help these oysters produce
beautiful cultured pearls.
Although Australia produces 60 percent of the world’s
South
Sea
cultured pearls, Indonesian farmers work more with the
gold-lipped oyster, and thus produce more golden pearls.
The silver-lipped variety produces equally beautiful
pearls that come in white to silver and often have rosé,
blue or green overtones. Aside from giving them a light
wash, pearl farmers do not treat South Sea pearls after
harvest.
Copyright
© 2007 by Amy Hourigan. All rights reserved.
A
graduate of the Gemological Institute of
America’s
Graduate Pearls program, Amy Hourigan is a fashion
writer and accessories buyer for Moon River Pearls.com,
an Internet-only jewelry store based in scenic Old Lyme,
Conn. Visit the store at
http://www.moonriverpearls.com. A pearl expert
and jewelry lover, Amy welcomes your jewelry questions.
Reach her at
ahourigan@moonriverpearls.com; visit her blog at
http://www.amysstylecafe.com. |
