Nacre

**Definition:** A biomineral consisting of layers of crystalized ARAGONITE, separated by interlamellar layers of organic matrix containing beta-CHITIN, and surrounded by an intercrystalline organic membrane of silk fibroin. Nacre is the iridescent substance better known as mother-of-pearl that is secreted by MOLLUSCS.

**Tree numbers:** - D01.146.275.500 - D01.200.275.150.150.500 - D01.578.200.500

**Synonyms:** - Mother of Pearl