Cultured pearls are produced by both freshwater and marine mollusks. Most of the world’s cultured pearls (known as freshwater pearls) are produced by freshwater mussels belonging to the family Unionidae. Most saltwater pearls are produced by three species of oysters belonging to the genus Pinctada, including Pinctada imbricata, Pinctada maxima, and Pinctada margaritifera.