Saltwater cultured pearls, originating from the oyster family of mollusks, are grown in Australia, China, the Cook Islands, French Polynesia, Indonesia, Japan, Korea, Malaysia, Mexico, the Philippines, Thailand and Vietnam. The most well known are Japanese Akoya white pearls and the larger South Sea pearls. The best-known "black" cultured pearls come from Tahiti and the Cook Islands. Pearl coloring varies based on the mollusk's genetics, minerals in the water and the plankton that it absorbs. Saltwater oysters are known to produce one or two pearls.

Freshwater cultured pearls, originating from the mussel family of mollusks, are cultivated in lakes, rivers and ponds. The United States, Japan, and China are the leading producers of these pearls. Freshwater mussels produce more than thirty pearls simultaneously. This is the most important factor affecting the price difference between saltwater and freshwater cultured pearls. Recent techniques have even made some saltwater and freshwater pearls indistinguishable.

Of all the pearl varieties, round pearls are the most rare. Baroque pearls - pearls that are not round - command lower prices, but also have beautiful irregular shapes. They are more common than round pearls and can be produced by both saltwater and freshwater mollusks. Symmetrical pearls have non-round symmetrical shapes like the teardrop or oval.

Akoya pearls tend to be the most well known saltwater cultured pearl variety. They are more perfectly round than most other pearls, and have a higher luster. They rarely exceed 10mm (millimeters) in diameter.

South Sea pearls are very large white pearls usually starting at 10mm in diameter and averaging between 11mm and 14mm. They are cultivated in the waters of Australia, Indonesia, and the Philippines. The pinkish white variety is the most prized, followed by the silvery-white variety.

Black pearls occur in sizes over 8mm and average 11mm to 12mm. These pearls are cultivated in the South Pacific and fine specimens are very rare and costly.