Fluorite (also called fluorspar) is the mineral form of calcium fluoride. It belongs to 

the halide minerals. It crystallizes in isometric cubic habit, although octahedral and 

more complex isometric forms are not uncommon.  

The Mohs scale of mineral hardness, based on scratch hardness comparison, 

defines value 4 as Fluorite. Fluorite is a colorful mineral, both in visible and 

ultraviolet light, and the stone has ornamental and lapidary 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 aberration, making them valuable in 

microscopes and telescopes. Fluorite optics are also usable in the far-ultraviolet 

and mid-infrared ranges, where conventional glasses are too absorbent for use.