A wide variety of pearl styles, colors and shapes exists, depending on where the pearl is sourced. Pearls are either sourced in freshwater – rivers, ponds, lakes – or the ocean’s saltwater.

Freshwater

Source: China, Japan, United States
Freshwater cultured pearls are easily cultivated from freshwater mussels rather than saltwater oysters. Freshwater culture pearls are produced in great abundance and are generally the most moderately priced of all cultured pearl varieties. Their unique shapes and pastel colors make them perfect gems for those on a budget.

Akoya

Source: China, Japan

Akoya pearls are the classic cultured pearls of Japan. They are the most lustrous of all pearls found anywhere in the world. In recent years, China has been successful in producing Akoya pearls within their own oceans but without the brilliant lustre of high-quality Japanese Akoya cultured pearls. They are known for their pure white or cream color, some with yellow, pink or blue hues. 

Mabe & Keshi Pearls

Source: Japan, Australia, French Polynesia, Indonesia, and the Philippines
Two types of pearls that don't develop into full spherical pearls are the Mabe and Keshi cultured pearls. Mabe are hemispherical pearls grown against the inside shell of an oyster rather than within the oyster's body. They are generally used in ring, earring and pendant settings which cover their flat backs or reverse side. Keshi cultured pearls are formed by accident entirely of nacre, with no “nucleus.” Their unusual shapes often lend them to clusters for bracelets or layered pearl necklaces.

South Sea

Source: Australia, French Polynesia, Indonesia, Mynamar
South Sea cultured pearls are grown in large tropical or semi-tropical saltwater oysters. They are the largest -- ranging in size from 10mm to 20mm -- and command premium prices because of their relative rarity. The most common colors are white, silver and gold.

Tahitian

Source: French Polynesia
The Black Tahitian pearl, found in the saltwater of French Polynesia, are extremely rare because only one out of 10,000 oysters contains a pearl. The oysters that create black Tahitian pearls, the Black Lipped oyster, once faced extinction and are now raised in the protected waters of pearl farms. Black Tahitian pearls range in size from 8mm to 25mm in diameter; those 12mm in diameter or larger are considered rare. Most Black Tahitian pearls are not black, but silver, gray, bronze, green with pink tones, and iridescent peacock.