About Apatite
The primary use of apatite is in the manufacture of fertilizer - it is a source of phosphorus. It is occasionally used as a gemstone. Green and blue varieties, in finely divided form, are pigments excellent covering power. Apatite is seldom found in jewelry stores and virtually unknown by the public, but collectors love the stone because of the many different colors, where the neon blue is the most favorite color. The stone is not that hard (5 on the scale of Mohs), which means it can easily be scratched by dust. This makes the stone suitable for earrings and pendants, but should be protected when used in rings.
Nice to know: Moon rocks collected by astronauts during the Apollo program contained traces of apatite.