Rocks and Minerals Information Sheet R009
The most common mineral which forms the bones and teeth of most animals is calcium phosphate which is the same material as Apatite. Being rich in phosphates Apatite is much used in the manufacture of fertilisers and in the pharmaceutical industry.
The name comes from the Greek meaning "to deceive" as it is often mistaken for other minerals. Apatite occurs in small amounts in most igneous and metamorphic rocks - it does also occur in sedimentary rock such as limestone.
It is distinguished from quartz by its lack of pointed crystal terminations and occasionally it is found to include rare earth elements. It is also sometimes used as a gemstone because some specimens when cut exhibit a "cat's-eye" effect.