Apatite is a phosphate mineral that has a hardness of 5 on the Moh's scale, making it too soft to be widely used as a gemstone for jewelry. Apatites are transparent to translucent, most commonly green, but can also be colorless, yellow, blue to violet, pink or brown. Transparent stones with good color, as seen here, can be faceted into gemstones. Major sources for gem quality apatite are Brazil, Burma, Madagascar, and Mexico. The beautiful intense blue color of this 23.25ct gem results from heat treatment of a naturally green stone. It is the largest faceted apatite from Madagascar in the National Gem Collection.