Mother of Pearl  (M.O.P.)   
Pinctada is the scientific name given to pearl oysters, distinguishing them from edible oysters known as Ostreidae. The larger South Seas oysters, Pinctada maxima, the silver- or gold-lipped pearl oyster.  The Tahitian pearl comes from Pinctada margaritifera of the variety cumingi, the black-lipped pearl oyster. Other varieties of Pinctada margaritifera are found throughout the tropical Indo-Pacific as far east as the Persian Gulf and as far west as the Gulf of California.