Lepidocrocite, an Apatite Mineral, and Magnetite in Teeth of Chitons (Polyplacophora)

Abstract

X-ray diffraction patterns show that the mature denticles of three extant chiton species are composed of the mineral lepidocrocite and an apatite mineral, probably francolite, in addition to magnetite. Each of the three minerals forms a discrete microarchitectural unit of the chiton denticles. This is the first indication that lepidocrocite is precipitated by marine organisms and an apatite mineral by chitons.