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PRECIOUS STONES
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Varieties of Pearl
The Oriental pearl is distinguished by its mellow skin and the soft tones which appear, whatever the color.
The
fresh-water pearl, even at its best, is characterized by a slightly
chalky appearance, and harshness as compared with the Oriental.
Pink
or conch pearls, pink to pale yellow and white, having a peculiar wavy
sheen, are distinguished by a hard china-like lustre. They are found in
the Gulf of California, and off the coasts of Mexico and West India
Islands.
Round,
pear, and egg-shape pearls are formed within the oyster, and are not
attached to the shell, the nucleus of their successive skins of nacre
being within themselves.
Button pearls are those having a flat underside.
Baroques are irregular and odd-shaped pearls.
Wing pearls are long and slim, resembling the closed wing of a bird, and are attached at some point to the shell during formation.
Blister
pearls are excrescences raised on the inner side of the shell by the
oyster in its effort to exclude a parasite which has intruded or bored
its way through the shell.
In all cases, pearls are successive layers of nacre deposited by the oyster over a nucleus of foreign substance.
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