apatite

ap·a·tite

noun \ˈap-ə-ˌtīt\

Definition of APATITE

: any of a group of calcium phosphate minerals occurring variously as hexagonal crystals, as granular masses, or in fine-grained masses as the chief constituent of bones and teeth and of phosphate rock; especially : calcium phosphate fluoride Ca₅F(PO₄)₃