ap·a·tite 
(ăpə-tīt′)
(ăpə-tīt′)n.
1. Any of a group of natural, variously colored calcium phosphate minerals containing fluorine, chlorine, or hydroxyl. These compounds form hexagonal crystals and are components of bones and teeth, are a source of phosphorus for plants, and are used in the manufacture of fertilizers.
2. See fluorapatite.
[From Greek apatē, deceit (from its often being mistaken for other minerals).]