Apatite / Fluorapatite
Apatite is a calcium phosphate with some fluorine, chlorine, and other elements. It describes a group of like isomorphous hexagonal phosphate minerals. The primary Apatite group includes Fluorapatite, Chlorapatite, and Hydroxylapatite. The extended Apatite super-group describes additional minerals such as Pyromorphite, Mimetite, and Vanadinite.
Apatite is named for the Greek word apate, which means "deceit", since Apatite is similar in appearance to many other minerals.
It can be difficult to tell the difference between individual members of the primary Apatite group. A designation of the specific Apatite type is not usually made, being called simply "Apatite" by collectors and dealers. However, most of the fine crystals and collector specimens are of the Fluorapatite type, which is by far the most common form of Apatite.