Watch Terminology Dictionary

Also known as MOP. A type of shellfish used to grow natural or cultured pearls. It primarily refers to pearl oysters such as Akoya pearls, Black-lipped pearl oysters, and White-lipped pearl oysters. In watches, thin slices of mother-of-pearl are attached to a metal base plate to decorate the dial. Colorful mother-of-pearl is often attached after the base plate has been painted.