Fluorite (also called fluorspar) is the mineral form of calcium fluoride. It belongs to the halide minerals. It crystallizes in isometric cubic habits, although octahedral and more complex metric forms are not uncommon.
The Mohs scales of mineral hardness, based on scatch hardness and comparison, defines value as fluorite.
Pure fluorite is colourless and transparent, both in visible and ultraviolet light, but impurities usually make it a colorful mineral and the stone has ornamental and lapidiary uses. Industrially, fluorite is used as a flux for smelting, and in the production of certain glasses and enamels. The purest grades of fluorite are a source of fluoride for hydrofluoric acid manufacture, which is the intermediate source of most fluorine-containing fine chemicals. Optically clear transparent fluorite lenses have low dispersion, so lenses made from it exhibit less chromatic abberation, making them valuable in microscopes and telescopes. Fluorite optics are also usable
