Cleavage marks are present on most crystals. Cleavage fragment s from large crystals are also prevalent; in octahedra, the cleavage fragments are flat, triangular shaped pieces, and cubic cleavage fragments are flat, three dimensional rectangles. Crystals frequently form penetration twin s, where one cube is intergrown in another " fluorite twin s". Also occurs as clusters of intergrown cubes, grainy , botryoidal , as spherical balls, and massive.
Transparent to translucent. Specific Gravity. Other ID Marks. Commonly fluorescent in a variety of colors. Complex Tests. In Group. Striking Features. Perfect cleavage , low hardness , and crystal habits. Hydrothermal ore vein s, sedimentary deposits, metamorphic environments, and pegmatite dike s.
Rock Type. Igneous , Sedimentary , Metamorphic. Popularity Prevalence Demand Antozonite - Variety of Fluorite containing uncombined fluorine ion s. Blue John - Banded purple and white or purple and yellow variety of Fluorite. Chlorophane - Variety of Fluorite that is thermoluminescent , emitting bright green light when heated.
Yttrocerite - Variety of Fluorite in which the element s cerium and yttrium partially replace the calcium in the chemical structure. The last fluorspar mine in Illinois closed in December Fluorspar is no longer mined anywhere in the United States. The General Assembly made fluorite the State Mineral in , when flourspar mining was a multimillion- dollar-per-year industry in Illinois. Over the years, much more fluorite has been mined in Illinois than in any other state.
Native Americans carved fluorspar to make artifacts, but the first recorded use of Illinois' fluorite was in , when fluorspar mined near Shawneetown in Gallatin County was used to manufacture hydrofluoric acid.
The chlorine in the compound is thought to damage the protective ozone layer that shields the earth from ultraviolet radiation. Click here for Ordering Information. Richard C. Berg, Director E. Peabody Champaign, IL info isgs. Newer equipment has rubber tires and is diesel operated, including the muckhaul units—which have buckets ranging in size from 0.
Drilling is done by diesel-propelled jumbos in the bedded ore mines, but the jackleg drills are still used in narrower working places and drifts. Vertical raises are used to facilitate ventilation requirements. Most drilling uses tungsten carbide bits, or the throwaway- type hardened steel bits.
In blasting, the trend is increasingly toward the use of ammonium nitrate—fuel oil mixtures. Mine crews, supervisors, and mechanics are usually provided with diesel personnel vehicles to facilitate mobility. Wherever widths of ore bodies, depths of overburden, economic stripping ratios, and the strength of the sidewalls permit, it is common practice to mine by open-pit methods, as is the case in Kenya and South Africa. This optimizes the obvious advantages to be gained by using lower cost explosives, large-scale earth-moving equipment, and economical quarry bench mining methods.
HF is a key ingredient for the production of all organic and non-organic chemicals that contain the element fluorine. Some specimens are known to glow a cream or white color. Many specimens do not fluoresce. Fluorescence in fluorite is thought to be caused when trace amounts of yttrium, europium, samarium, or other elements substitute for calcium in the fluorite mineral structure. Most fluorite occurs as vein fillings in rocks that have been subjected to hydrothermal activity.
These veins often contain metallic ores which can include sulfides of tin, silver , lead , zinc , copper , and other metals.
Fluorite is also found in the fractures and vugs of some limestones and dolomites. Fluorite can be massive, granular, or euhedral as octahedral or cubic crystals. Fluorite is a common mineral in hydrothermal and carbonate rocks worldwide. Fluorite unit cell: Illustration showing the relative size and position of fluorine and calcium ions in the isometric unit cell of fluorite.
Public domain image by Benjah-bmm Fluoride products: Most people are familiar with fluoride products used in the prevention of tooth decay. Fluoride is added to drinking water as a systemic fluoride therapy and added to toothpastes, mouthwashes and dental rinse as a topical fluoride therapy.
These uses of fluoride have been controversial. The best way to learn about minerals is to study with a collection of small specimens that you can handle, examine, and observe their properties. Inexpensive mineral collections are available in the Geology. Fluorite gemstone: Fluorite can be a beautiful gemstone when faceted.
It is mainly a gemstone for collectors because it has a hardness of 4 on the Mohs scale and because it cleaves easily in four directions. Fluorite has a wide variety of uses. The primary uses are in the metallurgical, ceramics, and chemical industries; however, optical, lapidary, and other uses are also important.
Fluorspar, the name used for fluorite when it is sold as a bulk material or in processed form, is sold in three different grades acid, ceramic, and metallurgical. Acid grade fluorspar is a high-purity material used by the chemical industry.
Most of the fluorspar consumed in the United States is acid grade even if it is used in lower grade applications. It is used mainly in the chemical industry to manufacture hydrofluoric acid HF. The HF is then used to manufacture a variety of products which include: fluorocarbon chemicals, foam blowing agents, refrigerants, and a variety of fluoride chemicals.
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