Pearl type
The two common Pearl Types are freshwater pearls and saltwater pearls. As their names indicate, freshwater pearls are produced by mussels living in freshwater areas such as lakes, rivers and streams. Saltwater pearls are produced by mollusks living in saltwater, such as oceans and marine bays.
Cultured pearl types can also be described by the four main types of pearls that are produced by freshwater and saltwater mollusks—these four types are: Freshwater pearls, Akoya pearls, Tahitian pearls, and South Sea pearls. Other cultured pearls do exist but are produced on a much smaller scale such as Cortez pearls from Baja California and Abalone mabe pearls from New Zealand and California.
Freshwater Pearls
Freshwater pearls are found naturally in rivers, lakes and other freshwater bodies of water. With a total production of 1,500 tons in 2006, China holds a monopoly over the pearl industry today. Freshwater pearls are cultured in all the surrounding provinces including: Zhejiang, Anhui, Jiangsu, Hubei, Hunan, and Jianxi. The largest marketplace for these freshwater pearls is the world's pearl trading hub, Hong Kong.
Akoya Pearls
Akoya pearls are the first type of commercially cultured and harvested whole pearls. Akoya pearls are cultured in the Pinctada fucata martensii, also known as the akoya oyster. Akoya pearls are currently farmed in Japan, China, Vietnam, South Korea and Australia in the Pinctada fucata martensii and Pinctada chemnitzii oyster. Many Japanese factories now import their smaller akoya requirements from China. The pearls are treated and strung in Japan so that they may still carry the mark 'Product of Japan'. It has been reported that more than 80% of the pearls 7 mm and smaller have come from Chinese farms regardless of whether or not they are sold by Japanese suppliers as Japanese pearls.
Tahitian Pearls
Tahitian pearls are produced in the black-lipped oyster ‘Pinctada margaritifera’, in and around Tahiti and the French Polynesian islands. Tahiti is the commercial center and trading hub for the bulk of the industry, however Tahiti does not have any pearl farms actually located on the island. The farms are instead scattered throughout French Polynesia, as far east as the Gambier Islands, and beyond French Polynesia to the west into the Micronesian Islands. Australia, the Seychelles and Vietnam have all produced black pearls as well, but those cannot be referred to as Tahitian pearls.
South Sea Pearls
South Sea pearls are cultured in the largest of all nacreous, pearl-bearing mollusk, the Pinctada maxima. South Sea pearls are farmed in Australia, Indonesia, the Philippines, Myanmar and Vietnam. Cultured South Sea pearls are known for the large size. There are four reasons South Sea pearls can grow to such large sizes. They are: the large size of the Pinctada maxima, the size of the implanted bead, the length of time the pearl is left to grow in the oyster, and the oyster’s environment. Due to the size of the oyster, it is able to accept a large bead. The gonad of the Pinctada maxima is several times larger than that of the akoya. Because of this larger gonad, the South Sea oyster is able to deposit nacre around the nucleus at a much quicker rate. South Sea pearls are considered to be the most valuable variety of cultured pearl.