Pearl-producing Mollusks

There are two types of pearl-producing mollusks: saltwater oysters and freshwater mussels. They belong to a subgroup of the mollusks, in which the shell consists of two hinged parts, known as bivalves. The shells of mollusks are secreted by a part of the body which is termed the mantle.

The most important pearl producers are bivalves of the genus Pinctada, from the highly prized saltwater pearls are obtained. Species of Pinctada tend to live in well-defined localities: different species predominate in different pearl fisheries.

Smaller white pearls are produced by the Japanese white-lipped Akoya oyster. Larger white and colored pearls, collectively known as South Seas pearl, come from larger species of oysters reared and the South Pacific and China. Black and grey iridescent pearls are produced by black-lipped oysters from Tahiti and the Cook Islands.