Which compound is the mineral fluorite, with the chemical formula CaF₂?

The mineral fluorite, with the chemical formula CaF₂, is calcium fluoride.

Calcium fluoride is an ionic compound made of calcium ions and fluoride ions in a 1:2 ratio. In nature, it occurs mainly as fluorite, a mineral that can appear purple, green, yellow, blue, or colorless because of impurities and defects in its crystal structure. Pure calcium fluoride is colorless and transparent.

Fluorite has been important as a source of fluorine and as a flux in metal processing. Its crystals also have useful optical properties, including transmission of a broad range of wavelengths, so synthetic calcium fluoride is used in some optical components and specialized instruments.

Calcium fluoride is not the same as sodium fluoride, which has the formula NaF and is used in some dental products. Fluorite should also not be confused with fluoride in water or toothpaste: “fluoride” refers to the fluoride ion or its compounds, while fluorite is the naturally occurring mineral name for CaF₂.