Tahitian Pearls
Tahitian pearls are found in a number of colours including grey, green and blue and colour variations are sometimes given exotic names such as Peacock, Moon Grey and Tahitian Gold. However the most famous is without doubt the black variety - to many people the phrase Tahitian pearl is synonymous with black pearl. You can buy a large variety of jewelry made with Tahitian cultured black pearls including necklaces, earrings and pendants.
Production
"Tahitian" pearls are produced not just in Tahiti itself but across many of the French Polynesian islands where they are farmed in the famed lagoons. Initially only natural pearls were available, however these were (and still are) extremely rare. Today almost all Tahitian pearls are cultivated using the Mikimoto method whereby an artificial nucleus is inserted into the oyster. The oyster cultivated is usually the black-lipped pearl oyster Pinctada margaritifera and they have been farmed since 1965. The oysters can easily grow up to a foot in diameter and weigh as much as 11 pounds. They can live for up to 30 years and are often "nucleated" several times during their life. Each successive pearl produced by a single oyster tends to be slightly larger than the one before but possibly slightly lower in quality.
Grading
As with many pearls, colour and lustre are the main qualities looked for when judging and valuing Tahitian pearls. For every 100 oysters nucleated, only around 30 produce pearls and maybe only a couple of these will be considered of top quality. Pearls can be rejected for a number of reasons including insufficient lustre, inadequate layer of nacre, visible internal nucleus and imperfections. Large, round pearls with good colour and lustre and few imperfections fetch the best prices.