I’ve never seen a nice definitive discussion of what the definitions
of various pearl types are, and of the diferences between related
types. There must be someone out there who can untangle these
strands!
I know pearls are formed by molluscs in response to an irritant in
the mantle - the irritant can be naturally-introduced (grain of
sand, etc) or something placed by human hands for the critter to
deposit a covering of nacre - a bead of glass or shell, a shape,
maybe even a low-quality pearl. But the labeling of the results has
me confused. Really valuable pearls are mostly natural and marine,
right?
What is the difference between “fresh-water pearls” and “cultured
fresh-water pearls”? “Fresh-water” and “biwas” pearls? Aren’t
almost all of the lower-priced pearls these days cultured and
fresh-water? Are all those irregularly-shaped, low-priced pearls on
temporary strands fresh-water, even if called just “cultured”? Are
there any un-cultured fresh-water pearls around? And I know the
fancy colors are mostly dyed or irradiated, but how about the creams
and peaches and other sort-of natural pastels? Can one tell?
For lots and lots of about pearls, you might consider
checking out Antoinette Matlins book on pearls, “The Pearl Book”
available from Amazon.com. Fred Ward has also written a book about
pearls, and although I haven’t read it myself, my general experience
with Fred’s books are that they’re all good.
Virtually all pearls in the marketplace today are cultured. The
term “cultured” refers to the fact that the pearl has been induced by
man; either through the insertion of a round shell bead nucleus,
created from shells of freshwater mollusks from the United States,
into a salt water oyster or through the insertion of a piece of
mantle tissue into a freshwater mussel (although some people now
claim that freshwater pearl growers are using freshwater pearls that
they have rounded off as starters for freshwater pearls as well).
Cultured pearls can be both inexpensive and expensive. Strands of
black Tahitian South Sea cultured pearls can run into the tens, and
sometimes even hundreds, of thousands of dollars. Strands of very
fine cultured Japanese cultured salt water pearls also are regularly
thousands of dollars, as are whatever the largest new freshwater
pearls that are in the market (It seems that every year they produce
larger and rounder freshwaters and when the new, larger size is
introduced they are always expensive. The price usually drops after
a few years when they have managed to step the size up another
notch.) On the other hand there are cultured low quality freshwater
pearls that can sell for a few dollars a strand.
There are virtually no natural pearls available anywhere in the
world today, except at auctions. Usually the pearls have aged quite
dramatically and are no longer nearly as attractive as they once
were. There are natural seed pearls available (very small pearls)
and occasionally someone will find a few naturals (I own one that
someone found off the coast of Baja CA) but they are virtually
unheard of for the most part. We used to be able to get Mississippi
River pearls, that I believe to be natural (from old stocks) that are
always wing shaped. These show up on and off in the marketplace and
quite often in antique jewelry.
All pearls are enhanced in some form, either through bleaching
processes, dying or irradiation. The dyed and irradiated pearls are
usually easy to recognize because the colors are so vividly intense
that it is quite obvious they aren’t natural. However there is some
material of a lighter tone that is dyed (check the silk for color)
and there are not many ways to tell if pearls have simply gone
through some bleaching process. Natural colors of pearls come from
a variety of factors, including but not limited to, the color of the
mollusk and the actual area where the starter is placed in the
mollusk.
You might want to look into taking a GIA course on pearls as a way
to vastly expand your knowledge of pearls and their differences.
Daniel R. Spirer, GG
Spirer Somes Jewelers
1794 Massachusetts Ave
Cambridge, MA 02140
617-491-6000 @spirersomes www.spirersomes.com
We used to be able to get Mississippi River pearls, that I believe
to be natural (from old stocks) that are always wing shaped.
Natural river pearls often, but not always, wing-shaped are still
being collected and are available from the American Pearl Company.
Take a look a t the following page and the 2 or 3 that follow it: http://americanpearlcompany.com/pearl_guide/6.htm