Apatite: group of minerals with a chemical composition corresponding to the formula Ca5[(F,Cl,OH)(PO4)3]. Ranges from transparent to opaque, with a luster from vitreous to greasy, and color from white to colorless, although other colors can also occur. Crystallizes in the hexagonal bipyramidal system and typically appears as polyhedral crystals with abundant flat surfaces, tabular or columnar crystals, as well as coarse granular or radial aggregates. Found in both magmatic and metamorphic rocks, as well as in phosphate rocks.
