www.edipeni.com - unique handicraft from Bali Indonesia, coconut shell, red coral handicraft, blicar shell handicraft, cinnamon

Nacre , also known as mother of pearl , is an organic-inorganic composite material produced by some mollusks as an inner shell layer. It is strong, resilient, and iridescent . For more information on shell structure see: Mollusc shell .

This substance is called "mother of pearl" because it is literally the "mother", or creator, of true pearls .

Nacre is found in certain ancient lineages of bivalves , gastropods and cephalopods . However, the inner-shell layer in the great majority of shelled mollusks is porcellaneous and non-nacreous, frequently resulting in a non-iridescent shine like that of a porcelain plate or, in some species, presenting non-nacreous iridescent effects such as 'flame structure' (e.g. conch pearl).

Pearls and the inside layer of pearl oyster shells and freshwater pearl mussel shells are made of nacre. Many other families of mollusks also have an inner shell layer which is nacreous, including marine gastropods such as the Haliotidae , the Trochidae and the Turbinidae .