The black pearl is a rare type of pearl which has a medium to dark gray color instead of the usual iridescent, whitish appearance of regular pearls. Black pearls are produced by the black-lip oyster (also called the Tahitian pearl oyster), Pinctada margaritifera, which is found in the southwestern Indian Ocean & Persian Gulf, southwestern Pacific Ocean, the Gulf of Mexico, and off the coast of Baja California, usually in relatively shallow waters (such as lagoons). The most common area where they were found is the southern Pacific Ocean, though. The black pearl is rare because the species that produces it has a smaller population than those which produce common pearls and the species which produces it tends to rarely produce pearls naturally. As a result, it is more expensive than standard pearls (the black pearl is not as valuable as the south sea pearl though).