it is refined into metal. As such, large amounts of fluorite are extensively used in open-hearth steel and steel enamelware production, the smelting of aluminum, as well as lead and antimony refining. It is also used in the manufacture of some types of glass, enamel, and porcelains.
The element fluorine has many uses in our industrial society, and fluorite is our major source of fluorine. Consequently large amounts of fluorite are used in the production of hydrofluoric acid and the manufacture of high-octane fuels, as well as the manufacture of flat panel displays and semiconductors. The first large scale manufacture of fluorine occurred during WWII, when it was used to separate and enrich the uranium needed for the Manhattan Project’s atomic bomb program. For better or worse, fluorine helped usher us into an atomic age and is still used to enrich uranium for nuclear power plants and weapons. Fluorine is also used to create a variety of non-reactive fluorocarbon resins that are used to line pipes, tanks and even cooking utensils. One of the latter is best known under the trade name of Teflon.
At one time, fluorite was also used in the manufacture of chlorofluorocarbons (CFC’s) that were used as refrigerants and in aerosol sprays, but more recently this use has been curtailed because of concerns over the role of CFC’s in the reduction of the Earth’s ozone layer. On a more beneficial side, fluorite is the source of fluoridated water and the fluoride compounds used in toothpaste and mouthwash that help to reduce dental cavities.
You might wonder exactly how fluoride treatments help prevent tooth decay and the answer lies in the effect of fluorine on another mineral called apatite. Apatite is a phosphate mineral that makes up much of our bones and teeth. When the bacteria that live in plaque on teeth are exposed to sugar, they produce weak acids that can dissolve some of the apatite present in enamel to create a porous tooth surface. If this process continues, eventually a ‘cavity’ forms. Apatite occurs in three main varieties and the one that naturally makes up the enamel layer of our teeth is called hydroxyapatite. If fluorine is present in your saliva, which it is after using fluoride toothpaste or drinking fluoridated water, then the apatite of the tooth enamel can alter to fluorapatite. Fluorapatite crystals are larger than hydroxyapatite crystals, so their relative surface area is less and they do not dissolve as easily as hydroxyapatite crystals. Hence teeth with enamel composed largely of fluorapatite will have far fewer cavities!
Fluorite is too soft to be used as jewelry, but the Romans mined a massive crystalline variety of fluorite, later known as Blue John or Derbyshire spar, that exhibited a distinctive color banding of blues, violets and purples. This banded fluorite was carved to create bowls, vases and ornamental objects that were extensively traded across Europe and the Mediterranean area. Although the Derbyshire deposits are now largely mined out, other varieties of fluorite are still among the most actively traded and collected mineral samples, as they occur in a wide range of colors and forms. As an example, for centuries the Chinese mined a green variety of fluorite, erroneously called ‘green quartz’, for carvings and figurines.
Clear fluorite is among the rarest of the many fluorite varieties and was once used in the manufacture of optical lenses. Modern fluorite lenses, though, are usually from commercially manufactured fluorite, rather than natural clear crystals.
In Our Future: The Environmental Implications of Fluorite Use
Fluorine taken from fluorite is an extremely reactive chemical. In small quantities it can provide medical benefits such as reduced dental cavities, but in larger quantities fluorine can be quite dangerous. Fluorine gas is a deadly poison. Combined with hydrogen, fluorine makes hydrofluoric acid, an acid so powerful that it is used to etch glass.
Perhaps fluorine’s most potent threat though, comes from its use in compounds that can be handled with little to no risk. Fluorine is u