The three are usually considered together due to the difficulty in distinguishing them in hand samples using ordinary methods. An irony of the name apatite is that apatite is the mineral that makes up the teeth in all vertebrate animals as well as their bones. Anyway, the name apatite comes from a Greek word meaning to decieve in allusion to its similarity to other more valuable minerals such as olivine , peridot and beryl . Large well formed crystals though can be found in certain contact metamorphic rocks. Very gemmy crystals of apatite can be cut as gems but the softness of apatite prevents wide distribution or acceptance of apatite as a gemstone.
Color is typically green but also yellow, blue, reddish brown and purple.
Luster is vitreous to greasy and gumdrop. Crystals are transparent to translucent. Also accicular, granular, reniform and massive. A cryptocrystalline variety is called collophane and can make up a rock type called phosphorite and also can replace fossil fragments. Cleavage is indistinct in one basal direction.