It occurs as the mineral fluorite (also called fluorspar), which is often deeply coloured owing to impurities.
[5] Although perfectly packed crystalline samples are colorless, the mineral is often deeply colored due to the presence of F-centers.
[6] It has been proposed that this is due to the fluoride ligands interacting with the electron core[7][8] or the d-subshell[9] of the calcium atom.
High purity CaF2 is produced by treating calcium carbonate with hydrofluoric acid:[10] Naturally occurring CaF2 is the principal source of hydrogen fluoride, a commodity chemical used to produce a wide range of materials.
[11] Hydrogen fluoride is liberated from the mineral by the action of concentrated sulfuric acid:[12] Calcium fluoride is used to manufacture optical components such as windows and lenses, used in thermal imaging systems, spectroscopy, telescopes, and excimer lasers (used for photolithography in the form of a fused lens).