A pearl is a hard, roundish object produced within the soft tissue of a living shelled mollusk. Just like the shell of mollusks, a pearl is composed of calcium carbonate in minute crystalline form, which has been deposited in concentric layers. The ideal pearl is perfectly round and smooth, but many other shapes of pearls occur.

The finest quality natural pearls have been highly valued as gemstones and objects of beauty for many centuries, and because of this, the word pearl became a metaphor for something very rare, very fine, very admirable and very valuable.

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I would like to share something on colors with you also, many white pearls have overtone colors referred to as tint. Pink or rose overtones are rare and expensive. Creamier overtones are also rare but not quite so expensive. Pearls with silver overtones are also highly coveted.

Pearls

A specific type of sea mollusk or oyster produces a Natural Pearl. Available in an infinite variety of colors, depending on the variety of oyster, the water temperature, the presence of minerals in the sea water, the degree of salinity and in the case of a cultured pearl, the choice of the mantle added during the culturing process.
Pearls, like any other products of nature, are never exactly alike. Although thought of as basically round, actually only about one percent is perfectly round. Pearls are available in an infinite variety of shapes from the irregularly shaped Baroque, Biwa and Mabe to the more round natural and cultured pearl.

Natural Pearl
A natural pearl is formed when an irritant, a small grain of sand of other minute object, finds its way into an oyster (not the edible variety of oyster). The irritant (nucleus) settles into the soft portion of the mollusk’s body between the shell and mantle. The oyster secretes a substance, nacre, as a protective measure, surrounding the nucleus in concentric circles building up lustrous layers of nacre that results in a pearl.

Cultured Pearl
A cultured pearl is grown in a mollusk/oyster that has been surgically implanted with an irritant known as the nucleus. Cultured pearls are genuine pearls as cultivated by man, accounting for their uniformity in both size and shape.

Most of the world’s cultured pearl production occurs primarily in Japan, as well as in Australia and the South Seas.

Baroque Pearl
A cultured pearl that is asymmetrical and free form in shape.

Biwa Pearl
A cultured pearl cultivated in a freshwater mussel in Lake Biwa, Japan. The term has been allowed to refer to any pearl cultivated in a freshwater mussel in Japan.

Mabe Pearl A dome-shaped cultured pearl cultivated on the inner shell of a mollusk rather than in its body. An assemblage of a cultured half-pearl and mother-of-pearl available in round, oval and pear shapes.

South Seas / Tahitian Black Pearl
The South Seas or Tahitian Black Pearl, as it is also known, is found in the Polynesian Islands, particularly in Tahiti. These pearls are produced by black-lipped oysters in a culturization process similar to that employed to produce Japanese cultured pearls. Tahitian Black Pearl are known for their high luster and color, ranging from light to dark gray, with bluish and/or greenish overtones, and of course their larger sizes.

Abalone Pearl
A naturally cultivated pearl from an Abalone, which is a univalve mollusk.

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Hope this article helps you guys!