Mother of Pearl is the name given to the iridescent coating on the inside of mollusk shells. When an object gets inside the shell of a mollusk, it will protect itself by coating the invading object with the same material it uses to coat pearls (nacre). This is where the name creator (mother) of pearls comes from. Nacre is found in pearl oysters, freshwater mussels and abalone. In China, mother of pearl was used to treat heart palpitations, high blood pressure, said to stimulate imagination and help with decision making. It is also used as a symbol of faith and innocence.
Note* Never use alcohol around mother of pearl because it will eat right through the coating, causing irreparable damage.