Fluorite (lat. fluor = flow), fluorspar, fluoride-class mineral, chemical composition CaF2. Sometimes Ca in small quantities is replaced with Y (yttrium-fluorite) rare-earth elements (TR), Sr, Mn, Na, U. It crystallizes in cubical system, forming so called fluorite structure. The crystals are in the form of a cube, octahedron etc.; the units are compact, macrocrystalline, grainy, earthy, (ratofkite). Hardness on mineralogical scale is 4, density 3180=3200 kg/m2, in yttrium-fluorite up to 3300 kg/m2, fusion point is 1360°C. Various coloration (yellow, green, violet etc.)It is quite often zonal, spotted due to formation of color centers. Luminescence under the influence of ultra-violet rays is typical for fluorite caused by foreign color centers in dark –blue-violet spectrum area (ions Eu2+) and in yellow-green area (ions Yb2+). Thermoluminescense is observed caused by ions Mn2+, TR3+. Isotropen has small dispersion, low refractive exponent (1,434), transparency in wave-length range 0,0125=10 mkm that makes fluorite a valuable optical raw material.

Fluorite is a widespread mineral of various origins. It is deposited in a wide temperature interval, hydrothermal and metasomatic as a rule. It is sometimes found in sediment (ratofkite). A very important typomorphic mineral of genetic mineralogy.

It is used in metallurgy as flux; in chemical industry for obtaining of hydrofluoric acid, cryolit; in ceramic production for manufacture of enamels, glaze. It is used as a feed stock for synthetic crystal growth F.; clear, transparent, colourless or faintly coloured sorts of F. It is widely used in optics for lens, object-glass and telescope manufacture as well as in the production of prisms for vacuum and X-ray spectrographs. Activated TR and U, synthetic fluorite laser material.