The Tahitian pearl is a particular type of bead-nucleated black pearl produced by the black-lip oyster (Pinctada margaritifera), which can be found in the waters of the South Pacific particularly in and around Tahiti and the French Polynesian islands. Although commonly referred to as a black pearl, the color of a Tahitian pearl actually ranges from different shades of gray, bronze, black, and green. These natural dark colors give the pearl its exotic beauty. A truly black pearl exists, but is extremely rare.
The black-lip oyster (Pinctada margaritifera) naturally secretes a black pigment which gives a Tahitian pearl its dark color. This mollusk can weigh as much as 10 pounds (4.5 kg) and is also known for its ornamental shell. Most Tahitian pearls available in the market are cultured pearls – produced in pearl farms. Natural black pearls are so rare that only a single pearl can be harvested out of 2,000 pearl oysters. The International Confederation of Jewelery, Silverware, Diamonds, Pearls and Stones (CIBJO) officially defines natural pearls as those created without human intervention. Tahitian cultured pearls are produced by the black-lip pearl oyster cultured in the lagoons of Tuamotu-Gambier Archipelago, a series of islands in French Polynesia.
The process involved in the formation of natural and cultured pearls is essentially the same. Pearl development begins when the oyster is irritated by the presence of a foreign particle such as a grain of sand or a piece of rock in its body. The oyster then employs its first line of defense which is to lay down an iridescent substance called nacre thereby forming pearl. In the case of cultured pearls, the irritant is inserted into the mollusk by pearl farmers themselves, whereas in natural pearls, the irritant gets into the mollusk by accident. Pearl quality depends on nacre quantity. The thicker the nacre becomes, the greater value the pearl gets. Pearl characteristics, such as luster and color, depend on the characteristic of the nacre itself. Likewise, a smooth surface means higher pearl quality. A round pearl of perfect quality with a diameter of 3.2 inches (18mm) cost as much as $10,000 US Dollars (USD).
Tahitian pearls are produced in pearl farms scattered throughout French Polynesia. Tahiti does not have black pearl farms actually located on the island, but it is where the trading hub for the bulk of the industry is located, hence the name Tahitian pearl. Tahiti is 28 miles (45 km) at it widest and is also famous for its black beaches.
Kokichi Mikimoto is credited with the first black pearl culture using the black-lip oyster at his pearl farm in Okinawa, Japan. Mikimoto's pearl farm was established in 1914. Jean-Marie Domard started the cultivation of the black-lip oyster to produce the Tahitian pearl in 1962. He established the first farm in the Hikuero Atoll in the Tuamato Islands in French Polynesia.