The black lipped oyster, pinctada margaritifera, produces the saltwater gems known as Tahitian black pearls. They are produced in the warm waters of French Polynesia.
What’s in a name
P. margaritifera is the only mollusk that produces these pearls, and they do so in places besides Tahiti. So, the name, Tahitian black pearls, is a bit misleading. For the oyster to thrive and for production to occur, the major requirement is that the water be warm. That being so, Tahitian black pearls can be found also in the Philippines, Hawaii, Fiji, Panama, and the Gulf of Mexico. But the “Tahitian” name sticks, no matter where p. margaritifera conducts its production.
A large oyster makes a large pearl
The Tahitian black pearl is a large pearl as pearls go. That’s because the black lipped oyster is a pretty big oyster as oysters go. The mollusk can grow to sizes approaching a foot across and ten pounds in weight. Its large infrastructure provides the growing room for pearls to grow large, with average pearl diameters from 8 to 14 mm, with larger ones produced on occasion too. The record holder is 21mm.
While the black lip is the only mollusk that produces black pearls, not all black lipped oysters produce pearls at all. A mere 30% of cultivated p. margaritiferas produce a pearl.
The black lipped oyster is encouraged to produce a pearl by the cultivation process. Cultivation consists of nucleating the oyster with a bead. The bead is usually round and made of mother-of-pearl or similar hard shell-like substance. A person nucleates the oyster by prying the bi-valve shell open and inserting the bead.
The bead is an irritant to the oyster. For its own comfort, the oyster internally exudes a saliva called nacre, which soothes the irritating effect of the nucleating bead. Layers upon layers of nacre build up, and for time periods up to two years, the bead is covered with the slimy secretions that result in a lustrous pearl. Two years! And there’s only one pearl! And remember, only three out of ten oysters so cultivated produce one pearl in those two years.
While Tahitian black pearls cannot be called rare, neither can they be regarded as all that common. Because p. margaritifera produces one pearl at a time, taking two years to do it and doing it only after a human being has intervened, Tahitian black pearls are uncommonly uncommon.
Give reverence to that mother of pearls, the black lipped oyster, and value the beauty of its dark gems of the sea.