CaF2

Calcium fluoride (CaF2), commonly known as fluorite or fluorspar, is an inorganic compound and mineral composed of calcium cations and fluoride anions in a 1:2 ratio. It forms cubic crystals and occurs in a wide range of colors depending on impurities. Fluorite is the principal source of fluorite and is widely distributed in hydrothermal veins and sedimentary rocks.

Physical and optical properties: chemical formula CaF2; molar mass about 78.08 g/mol; crystal system is isometric with a cubic structure; Mohs hardness 4; density about 3.18 g/cm3; perfect octahedral cleavage in four directions; transparent to translucent with a glassy luster. It transmits light from the near ultraviolet through the visible spectrum and well into the mid-infrared, approximately 130 nm to 8 μm, and is notable for ultraviolet fluorescence in many specimens.

Occurrence: fluorite forms in hydrothermal veins in limestones and dolostones, as well as in skarn and replacement deposits. It is commonly associated with quartz, sphalerite, barite, and calcite. Major producing regions include China, Mexico, Spain, Germany, and the United States.

Uses: it is used as a flux in steelmaking and as a source of fluorine compounds for various chemical processes; in ceramics, glass, and enamel production. Synthetic CaF2 crystals are widely used as optical materials for ultraviolet and infrared windows and lenses in spectroscopy, lithography, and laser systems due to their wide transmission and low dispersion.

Safety and handling: fluorite is relatively low in toxicity, but dust should be avoided to minimize inhalation. It is insoluble in water but can release hydrogen fluoride when reacted with strong acids; standard mineral-handling precautions apply.