The oyster itself is small for the size of the shell.
This specimen is found on the coast of Ceylon, Persian Gulf, Japanese, Mexican and California coasts, the western shores of South America, Brazil, West Indian Islands, Panama, Sooloo Archipelago, and the northeast and northwestern coast of Australia.
The fresh-water or unio margaritifera is an even, egg-shaped mussel found in brooks, rivers, and lakes in temperate zones in nearly all parts of the world.
Some fine river pearls have been found in the United States, but most of the American pearls are of a button or elongated shape, or are baroques or fancy-shaped.
In China many people engage in the business of making small pellets of clay or metal images, which in the month of May are introduced into the river mussels (mytilus cygneus).
The mussels are replanted, and in November they are taken up again. Some of the oysters die, but most of them are found to have been actively at work covering the little pellets or metal figures with nacre, and while no strictly first-class pearls are formed in this way, many curious little pearl figures or gods are made and sold to the curious or devout.
Pink or conch pearls are found in the Gulf of California and coasts of Mexico, Bahama Islands, West Indian Islands, and in some rivers in South America.
They seldom occur in regular shapes, and although they are termed pink pearls, they range in color from red to pale yellow, and are often found of a china-white color.
The pink pearl displays a wavy appearance and a peculiar sheen, something like watered silk. As the pink pearl is seldom found perfectly round and of a good color, such a specimen is very valuable.