Types of Pearl
Common Types of Pearls
Akoya pearls are cultured saltwater pearls which are cultivated from the oyster species Pinctada fucata martensii, primarily in Japan and China. Renowned for their luster, Akoya pearls are the pearls most often used in necklaces. They are generally white or cream colored, and have overtone colors of rose, yellow, or green.
After the development of modern pearl culturing techniques by Kokichi Mikimoto in the early part of the 20th century, akoyas from Japan became the first pearls to be cultured on a large scale.
The akoya oyster is the smallest pearl-producing oyster, so Akoya pearls also tend to be small, ranging in size from about 2 to 11 millimeters. They also tend to be the most consistently round and near-round pearls, making them ideal in terms of matching for multi-pearl jewelry such as strands, bracelets, etc.
Freshwater pearls are often somewhat less lustrous than their saltwater counterparts. However, they appear in a wide variety of shapes and colors, and they tend to be less expensive than saltwater pearls, making them quite popular. Freshwater pearls are also quite durable, resisting chipping, wear, and degeneration.
Freshwater pearls differ from other cultured pearls in that they are not bead-nucleated. Freshwater mollusks are nucleated by creating a small incision in the fleshy mantle tissue and inserting a piece of mantle tissue from another oyster. The result is a pearl composed of solid nacre, and the mantle tissue is eventually dissolved or drilled out, but without a bead nucleus to guide the growth process, the pearls are rarely round.
Black Tahitian pearls are produced by the black-lipped oyster (Pinctada margaritifera) in the islands of French Polynesia. The oyster itself is quite large -- sometimes up to 12 inches across and weighing as much as 10 pounds -- which often results in much larger-than-average pearls. The pearls are unique because of their natural dark colors.
South Sea pearl
South Sea pearls are among the largest commercially harvested cultured pearls in the world. The average size of a South Sea pearl is 13mm, with most harvests producing a range of sizes from 9mm up to 20mm.
The South Seas lie between the northern coast of Australia and the southern coast of China. These waters are the native habitat of the large oyster, the Pinctada maxima. This oyster grows up to 12 inches in diameter, and can be nucleated with a much larger bead than other saltwater oysters such as the Akoya.