Buying pearl jewelry can be fun, exciting and confusing. Whether
you’re considering a gift of pearl jewelry for someone special
or as a treat for yourself, take some time to learn the terms
used in the industry. Here’s some information to help you get
the best quality pearl jewelry for your money, whether you’re
shopping in a traditional brick and mortar store or online.
Pearls Natural or real pearls are made by oysters and other
mollusks. Cultured pearls also are grown by mollusks, but with
human intervention; that is, an irritant introduced into the
shells causes a pearl to grow. Imitation pearls are man-made
with glass, plastic, or organic materials.
Because natural pearls are very rare, most pearls used in
jewelry are either cultured or imitation pearls. Cultured
pearls, because they are made by oysters or mollusks, usually
are more expensive than imitation pears. A cultured pearl’s
value is largely based on its size, usually stated in
millimeters, and the quality of its nacre coating, which give it
luster. Jewelers should tell your if the pearls are cultured or
imitation. Some black, bronze, gold, purple, blue and orange
pearls, whether natural or cultured, occur that way in nature;
some, however, are dyed through various processes. Jewelers
should tell you whether the colored pearls are naturally
colored, dyed or irradiated.
Clams, oysters, mussels and many other mollusks with limy shells
are known to produce pearls. But very few kinds yield gem pearls
of jeweler’s quality. The pearl is an abnormal growth of
mother-of-pearl, or nacre, imbedded in the soft bodies of these
shellfish. It is built up, layer upon layer, in the same way as
nacre is added to the lining of the growing shell and always has
the same color and luster. For example, over the country,
hundreds of good-sized pearls are found each year in the oysters
we eat. Unfortunately these have no commercial value regardless
of whether they have been cooked or not because they are dull
opaque white or purple like the shell of the parent oyster. In
recent times almost all pearls of gem quality come from the
oriental pearl oyster which has a bright shimmering translucent
nacre.
A pearl starts growing when some irritating foreign substance
such as a sand grain, bit of mud, parasite or other object
becomes lodged in the shell-producing gland called the mantle.
Pearls formed in the soft flesh where nacre can be added on all
sides are most likely to be spherical and the most highly
prized. By far the great majority are flattened or variously
distorted and have little value. Size, color, luster and freedom
from flaws are other essential qualities. Unlike other gems,
such as diamonds, pearls have an average life of only about 50
years. In time the small amount of water in a pearl’s make-up is
lost and its surface cracks. Because they are mostly lime,
necklaces which are worn often are injured by the acid
secretions of the human skin.