Apatite is rare gemstone which is found in a great variety of colors and transparency, but it's generally soft gems to make a satisfactory jewelry. The most common colors including yellow, green, blue, green, and violet, but there seems to be no red apatite. Apatite is sometimes contain massive fibrous structure which led to producing chatoyancy or cat's eye effect when cut in cabochon. Apatites occure worldwide, however, gem material comes mostly from Brazil, Mexico, Madagascar, Sri Lanka, and Myanmar.
This mineral is composed of calcium phosphate and it may interest you to know that the dentine of teeth is mainly apatite.