|Also called: nacre a hard iridescent substance, mostly calcium carbonate, that forms the inner layer of the shells of certain molluscs, such as the oyster. It is used to make buttons, inlay furniture, etcRelated: nacreous|
The hard, smooth, pearly layer on the inside of certain seashells, such as abalones and certain oysters. It is used to make buttons and jewelry. Also called nacre.