Black pearls are rare. They are produced by the black-lip oyster (Pinctada margaritifera) and can be black, silver, charcoal or a deep peacock green. In the wild, black pearls are hard to find, because the black-lip oyster does not often produce pearls. Cultivated black pearls are more common than natural ones, but still rare. Many black pearls are dyed.
Black pearls are often larger in size than white pearls. The most common colors are silver and gray. A true black and peacock green are the rarest in the color spectrum.
Although every shelled mollusk has the potential to produce pearls, many do not. In the wild, only 1 oyster in 15,000 contains a black pearl. For white pearls this average ratio is 1 oyster in 10,000.
The pearl's color is because of a dark liquid secreted by the oyster.
Black pearls can be either natural or cultivated. Cultivated pearls have been "seeded" by a human-introduced irritant. Most black pearls are cultured in lagoons across the Indo-Pacific.
Cultivated black pearls are allowed to grow for 2 to 5 years. A black-lip oyster that has produced a high quality pearl can be seeded 2 times.
Small, cultured black pearls start at about $100. An 18 mm pearl of high quality can cost as much as $10,000. In comparison, small, cultured white pearls start around $40.