na·cre | ˈnā-kər
noun
The shiny, iridescent substance secreted by a mollusk as a response to an irritant (like a piece of sand), which over time builds up to become a pearl
Nacre is the composite material, made of partially organic and partially inorganic compounds on the inside of a mollusk’s shell. Secreted by the mollusk, the shiny material is produced often because of an irritant that has gotten inside, like sand or debris. The nacre can build up over time to form pearls inside of the shell. The nacre itself is also sometimes known as mother-of-pearl and can be harvested and used as an inlay for furniture, accessories, and some kinds of jewelry. Nacre is found in a number of different types of mollusk shells including clams, snails, tusk shells, and chiton shells.
