Fluorite (also called fluorspar) is a halide mineral composed of calcium fluoride, CaF2. It is an isometric mineral with a cubic habit, though octahedral and more complex isometric forms are not uncommon. Crystal twinning is common and adds complexity to the observed crystal habits. The word fluorite is derived from the Latin root fluo, meaning ''to flow'' because the mineral is used as a flux in iron smelting to decrease the viscosity of slags at a given temperature. This increase in fluidity is the result of the ionic nature of the mineral. The melting point of pure calcium fluoride is 1676 K. In 1852 fluorite gave its name to the phenomenon of fluorescence, which is prominent in fluorites from certain locations, due to certain impurities in the crystal. Fluorite also gave the name to...'
Contributions by Vsmith, PeterGHughes, and Arpingstone.