Where is fluorine found in nature on Earth?

Elemental fluorine is too reactive to persist naturally on Earth for long, so it is found only in compounds. One of the best-known fluorine-bearing minerals is fluorite, also called calcium fluoride, while cryolite and apatite are other important sources. Fluorine compounds are widespread in rocks, groundwater, and biological systems in trace amounts. The element was first isolated in 1886 by Henri Moissan, a landmark achievement in chemistry. Today, fluorine compounds are used in toothpaste, pharmaceuticals, refrigerants, and industrial chemistry.