Apatite is "any group of calcium phosphate minerals occurring variously as hexagonal crystals, as granular masses, or in fine-grained masses as the chief constituent of phosphate rock and of bones and teeth; especially: calcium phosphate fluoride," according to Merriam-Webster's dictionary. It is a common phosphate mineral. It is found in igneous, sedimentary and metamorphic rock, in phosphorite and in some hydrothermal veins and in iron rich igneous deposits along with feldspar, quartz and iron ores. There are three minerals that actually contribute to Apatite, which is the reason for the varied colors and shades of this stone. Apatite is Calcium Phosphate combined with fluorine, chlorine or hydroxyl. These three minerals are usually found in every specimen but some specimens have been known to have 100% of one or the other. It is often hard to spot the difference between the three minerals in hand samples of this stone. Therefore, they are often considered together in Apatite.