Introduction of Fluorite

Fluorite, a mineral that melts easily, derives its name from the Latin word "fluere" meaning "to flow" or "to flux" and refers to its use as a flux in the steel and aluminum smelting process. The word "fluorescent" comes from the word Fluorite, as Fluorite crystals were some of the first fluorescent specimens to be studied. Its fluorescence is thought to be due to Yttrium, Cerium or organic matter in the crystal structure.   

Fluorite was originally known as Fluorospar or Fluor Spar and has been called "the most colorful mineral in the world" as its colors are many; the most common being purple, blue, green, yellow, pink or clear, but it is not uncommon to find specimens in white, red-orange, black, brown and every color and shade in between. It is also not uncommon to find multi-colored Fluorite (sometimes called Rainbow Fluorite) that possess several different bands of color (called "zones") that intermingle, producing a more highly sought after variation of the stone. One older locality that is the sole source of the well-known and well-loved banded purple-blue variety of Fluorite called "Blue John Fluorite" is found in Castleton in Derbyshire, England. This area has been mined since ancient Roman times and is now depleted. Other notable localities of Fluorite mines are found in Germany, Norway, Austria, Switzerland, Canada, China, Italy, and the United States. 

Fluorite is calcium fluoride and forms at shallow depths in relatively cooler conditions than what many other types of crystals form at. It usually occurs as transparent or translucent cubic or octohedronal crystals and is most commonly found in metallic hydrothermal vein deposits, especially those pegmatite cavities containing Lead, Zinc, Silver, Galena or Sphalerite. Fluorite can also occur in sedimentary rocks, or may be found in Granites or Limestones or as a component of other metamorphic rock. 

Fluorescent minerals are popular with collectors, and Fluorite tops the list there. Along with the crystal's magnificent color display under an ultra-violet (UV) light, many specimens are also thermoluminescent, meaning they will glow when heated. One particular variety, Chlorophane (meaning "to show green"), will exhibit this property when even simply held in one's hand, being activated by merely body heat. It will glow green to blue-green, once and only once, as the glow eventually fades away no longer able to be activated. Limited quantities of this type of Fluorite are found in Franklin, New Jersey; the Bluebird Mine, Arizona; Amelia Court House, Virginia; Mont Saint-Hilaire, Quebec, Canada, and Nerchinsk, Ural Mountains, Russia. 

Minerals associated with Fluorite are Calcite, Quartz, Barite, Galena, Willemite and many more. Fluorite is second only to Quartz as being the most popular mineral for collectors, but is not popular as a gemstone for, unlike Quartz, it can be easily scratched or broken. Purple Fluorite can be hard to tell apart from Amethyst, but a simple hardness test will reveal which is which. Fluorite is much softer than Amethyst, being only a 4.0 on the Mohs Scale.