Fluorite has many industrial uses: as a flux in the manufacture of steel; in the production of hydrofluoric acid; and as a catalyst in the manufacture of high-octane fuels. It is used in the manufacture of artificial cryolite, for the refining of aluminum, lead, and antimony, in the formation of opalescent glass and in iron and steel enamelware. Fluorite is also a source of fluorine, which is used for the fluoridation of water and in Teflon coating, where the fluorine helps to provide the “nonstick” surface on Teflon cooking pans.
Blue john is a variety of fluorite with curved bands of blue, purple, violet, yellow, and white. These distinctive colors were made millions of years ago either by the inclusion of manganese or oil. Blue john is fragile and may be bonded with resins to help protect against damage. The only source in the world for Blue john is Castleton, in Derbyshire, England. It was used by the ancient Romans for ornamental objects. It became very popular in the late 18th and 19th centuries, when it was used to fashion vases, urns, and dishes.
Fluorite is found worldwide. Major sources are found in the United States in Halliburton County; Hastings County; in Ontario, Canada; Trigo Mountains, La Paz County, Arizona; San Juan County, Colorado; Cave-in-Rock, Hardin County, Illinois; Franklin, New Jersey and Socorro County, New Mexico. Also in South Australia, and Alsace, northeast France.
Fluorite can be confused with many gemstones, due to its richness of color.