Mother of Pearl

Mother-of-pearl is the iridescent inside lining of a mollusk shell. It is most commonly found in three types of mollusks—pearl oysters, freshwater mussels, and abalone. To protect the inside of their shells from parasites and foreign irritants, the mollusk coats it with nacre—an organic substance that gives mother-of-pearl its iridescent effect and distinct beauty. This multicolored iridescence is caused by the way light reflects on the layers of nacre on the shell.