The Culture of Freshwater Pearls
Jacqueline Kennedy epitomized the glamor to which women could
aspire with a strand of quality pearls.
© by Fred Ward
A great irony of pearl history is that the least expensive cultured pearl
product in the market today rivals the quality of the most expensive natural
pearls ever found. The price-value anomaly is obvious to consumers as they
hasten to buy Chinese freshwater bargains. Indeed, pearls from freshwater
mussels lie at the center of the liveliest activity in pearling
Natural freshwater pearls occur in mussels for the same reason that saltwater
pearls occur in oysters. Foreign material, usually a sharp object or parasite,
enters a mussel and cannot be expelled. To reduce irritation, the mollusk coats
the intruder with the same secretion it uses for shell-building, nacre. To
culture freshwater mussels, workers slightly open their shells, cut small slits
into the mantle tissue inside both shells, and insert small pieces of live
mantle tissue from another mussel into those slits. In freshwater mussels that
insertion alone is sufficient to start nacre production. Most cultured
freshwater pearls are composed entirely of nacre, just like their natural
freshwater and natural saltwater counterparts.
The Chinese were the first to culture a product from freshwater mussels,
though their centuries-old Buddhas are not true pearls but shell mabes. The first
cultured freshwater pearls originated in Japan. Quite soon after their initial
success with cultured saltwater pearls, Japanese pearl farmers experimented
with freshwater mussels in Lake Biwa, a large lake near Kyoto. Initial
commercial freshwater pearl crops appeared in the 1930s. The all-nacre Biwa
pearls formed in colors unseen in saltwater pearls. Almost instantly appealing,
their lustre and luminescent depth rivaled naturals because they, too, were
Throughout most of this century, the Japanese
dominated the cultured-pearl industry.
Even though World War II interrupted the flow of Lake Biwa pearls, by the
1950s strands sold in Japan as less expensive, colorful alternatives to the
mainstay material, cultured saltwater pearls. Biwas' success and publicity were
so effective that until a few years ago, all freshwater pearls were routinely
referred to as "Biwas," no matter their origin or that such references are
illegal in the U.S. unless the pearls are actually from Biwa. When I first
visited Lake Biwa in 1973, freshwater pearl production still thrived. But,
although the lake supplied most of the world's freshwater pearls, there were
warning signs as development pressed toward its shores. On a return trip in
1984, I observed that Biwa's pearl farms were barely surviving, because of
pollutants washing in from farms, resorts, and industries around the lake.
As Biwa production diminished, China filled the vacuum. China has all the
resources that Japan lacks: a huge land mass; countless available lakes,
rivers, and irrigation ditches; a limitless and pliable work force that earns
less than a dollar a day; and an almost desperate need for hard currency. In
1968, with no recent history in pearling, China startled the gem world with
prodigious amounts of ridiculously inexpensive pearls.
saltwater pearls from Japan have now met their match in cultured freshwater
pearls from China.
Unfortunately for China's reputation as a producer and for the impression left
with the public, the initial Chinese offering, what I call the First Chinese
Pearl Wave, in the 1970s and 1980s, appeared trivial. Immediately dubbed "Rice
Krispies," the oddly shaped material with a crinkly surface dyed any number of
"pop" colors could in no way compete with the best from Lake Biwa. The Second
Wave barely rippled the market but was an important evolutionary step. Between
1984 and 1991, China learned fast and well, mastering techniques and producing
better shapes and colors. Buying expertise from Japan and the U.S., the Chinese
China's Cultured Pearl Revolution
Black pearls from the South
Pacific also come in a range of colors.
Now China is in what I call its Third Pearl Wave. Starting in the 1990s, China
surprised the market with products that are revolutionizing pearling. The
shapes, luster, and colors of the new Chinese production often match original
Biwa quality and sometime even surpass it; certainly the new orange and
peach-colored pearls are unique. As testimony to China's achievement, their
freshwater pearls are round enough and good enough to pass as Japanese akoya.
China already sells round white pearls up to 7mm for perhaps a tenth the price
of Japanese cultured saltwater pearls.
Bleaching, dying, and polishing do occur. Except for the old Arabic practice
of sun-bleaching in the Persian Gulf, naturals were practically never
processed. Chinese pearls that are nearly white or mottled are usually bleached
to make them whiter and more uniform. With the same methods perfected by the
Japanese, the Chinese use a mild bleach, bright fluorescent lights, and heat.
They polish surfaces by tumbling pearls in pumice or similar substances. The
idea, as always, is to facilitate matching pearls for strands. Many Chinese
pearls used to be dyed in the 1980s to bright red, blue, lavender, yellow or
even black. In response to contemporary preferences, they now offer a selection
of subtle natural colors.
The Chinese have also begun to nucleate some of their freshwater mussels with
shell nuclei implants in both the creatures' bodies as well as in their
mantles. Such practices, once perceived as "saltwater culturing techniques,"
are a new cultural revolution. How will buyers react who had been told that
cultured freshwater pearls were all-nacre products? Will they buy Chinese
pearls if the roundest examples are nacre-coated shell beads instead? How will
such new products be positioned in the market? Will anyone, including gem
testing labs, be able to tell the difference between tissue-nucleated and
bead-nucleated freshwater pearls?
Nucleating an oyster.
Those are serious new considerations. Even more disquieting is the second
innovation. The Chinese are nucleating mussels with their own tissue-cultured
freshwater pearls, which result in all-nacre round or almost round pearls.
Aiming for an even higher percentage of rounds, the Chinese are even reshaping
reject freshwater pearls into spheres, then nucleating mussels with them.
When combined, those two nucleation innovations are astounding developments.
Once again the Chinese have radically altered freshwater culturing, making
saltwater and freshwater techniques indistinguishable. They have also
introduced a new type of culturing, nucleating with small tissue-nucleated
pearls. Some of China's new pearls are all-nacre, some have nacre-coated
nuclei, all are unmarked. After one experimenter used small off-round naturals
as nuclei, he sent the resulting freshwater pearls to a gem lab and received a
report identifying them as "naturals." If pearl farmers can grow cultured
pearls that test as naturals, the market may be in for a wild ride.
"If pearl farmers can grow cultured pearls that test as naturals, the market
may be in for a wild ride."
Fred Ward is a gemologist and author of the book Pearls (Gem Book
Publishers, Bethesda, Maryland, 1998), from which this article was adapted.
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© | Updated November 2000