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Chemical Formula | CaF2 | ||||||||||||||||||||||||||
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Composition | Calcium fluoride | ||||||||||||||||||||||||||
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Color | Occurs in all colors. Multicolored specimens also exist. | ||||||||||||||||||||||||||
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Streak | White | ||||||||||||||||||||||||||
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Hardness | 4 | ||||||||||||||||||||||||||
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Crystal Forms and Aggregates |
(Isometric) Most commonly octahedrons and cubes. Seldom occurs in dodecahedral crystals. Crystals are frequently combinations of octahedrons and cubes, and dodecahedral growths are sometimes present, forming complex and interesting crystals. Cleavage marks are present on basically all crystals. Cleavage fragments from large crystals are also found. From octahedrons, the cleavage fragments are flat, triangular shaped pieces. Cubic cleavage fragments are flat, three dimensional rectangles. Crystals frequently form penetration twins, where one cube is intergrown in another. Also occurs as clusters of intergrown cubes, grainy, and massive. | ||||||||||||||||||||||||||
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Transparency | Transparent to translucent | ||||||||||||||||||||||||||
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Specific Gravity | 3.0 - 3.3 | ||||||||||||||||||||||||||
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Luster | Vitreous | ||||||||||||||||||||||||||
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Cleavage | 1, all sides - octahedral (even on cubic faces) | ||||||||||||||||||||||||||
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Fracture | Conchoidal | ||||||||||||||||||||||||||
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Tenacity | Brittle | ||||||||||||||||||||||||||
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Other ID Marks | Commonly fluorescent in a variety of colors | ||||||||||||||||||||||||||
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Other Names |  Fluorspar,  Fluor |
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Varieties | 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. Yttrofluorite
- Variety of Fluorite in which yttrium partially replaces
the calcium in its structure. Formula = (Ca,Y)F2 Yttrocerite
- Variety of Fluorite in which cerium and yttrium
partially replaces the calcium in its structure. Formula
= (Ca,Ce,Y)F2 Antozonite
- Variety of Fluorite containing uncombined fluorine ions.
When fractured or cleaved, this variety gives off a peculiar odor. |
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In Group | Halides | ||||||||||||||||||||||||||
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All About | Fluorite comes in basically every color,
although pure Fluorite is colorless. The color variations
are caused by various impurities, which are usually hydrocarbons. The hydrocarbons, and thus the
coloring, can be removed from a specimen by heating. Fluorite has interesting cleavage habits. The perfect cleavage parallel to the octahedral faces can sometimes be "peeled" off to smooth out a crystal into a perfect octahedron. Fluorite is one of the more famous fluorescent minerals. Many specimens strongly fluoresce, in a great variation of color. The word "fluorescent" is derived from the mineral Fluorite. The name of the element fluorine is also derived from Fluorite. |
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Uses | Fluorite is the only mineral for which
significant quantities of the important element fluorine
can be obtained. Fluorite is also used as a flux
in the manufacture of steel and other metals to eliminate
impurities. There is a great demand for Fluorite in
the optics field, and to meet it synthetic crystals are
grown to produce special lenses. It is used in the
production of certain glass and enamel. Ornamental objects have been found carved from Fluorite. It is soft and creates beautiful ornaments if a large enough chunk is found. Fluorite very often occurs in unflawed crystals in beautiful colors, but its softness prevents it from being a gemstone and it is only faceted for collectors. Fluorite is a very popular mineral among collectors, and millions of crystals are sold each year to collectors. |
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Striking Features | Perfect cleavage, hardness, and crystal habits | ||||||||||||||||||||||||||
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Complex Tests | Red and green fluorite become phosphorescent if heated higher than 212º F (100º C) | ||||||||||||||||||||||||||
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Popularity (1-4) | 1 | ||||||||||||||||||||||||||
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Prevalence (1-3) | 1 | ||||||||||||||||||||||||||
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Demand (1-3) | 1 | ||||||||||||||||||||||||||
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Distinguishing Similar Minerals |
Calcite - slightly softer (3), different
crystal forms Quartz - much harder (7), no cleavage Apatite - harder (5), different crystal form Halite - softer (2 - 2½), has a salty taste |
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Commonly Occurs With |
Calcite, Quartz, Barite, Galena, Pyrite | ||||||||||||||||||||||||||
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Noteworthy Localities |
Fluorite occurs throughout the world, but
only a handful of localities have produced large
quantities of high quality Fluorite. England has produced
some of the finest specimens, in areas such as Durham
(especially in Weardale), Cornwall, Cumberland, and
Derbyshire. Pink octahedrons were found in Göschenen,
Switzerland, and are in great demand. Fine crystals were
also found throughout Spain, Peru, Russia, Kazakhstan,
Germany; Hunan Province, China; and Tuscany, Italy. Canada has produced some fine crystals, in Wilberforce, Haliburton Co., Ontario, and deep green crystals in Hastings Co., Ontario. Mexico has also produced choice specimens, in Mapimi, Durango (colorless cubes), and Niaca and Musquis, Chihuahua (violet cubes). The U.S. also has many fine occurrences. Hardin Co., Illinois, has produced more collectible specimens than anywhere in the U.S., in places like Rosiclare, Cave In Rock, etc. There are numerous other noteworthy deposits: Marion, Crittenden Co., Kentucky; Clay Center, Ottawa Co., Ohio; Rimer, Putnam Co., Ohio; Pea Ridge Mine, Sullivan Co., Missouri; Carthage, Smith Co., Tennessee; Grant Co., New Mexico; Barstow mine and Silverton, Ouray Co., Colorado; Penfield, Monroe Co., New York; and Walworth, Wayne Co., New York. Green octahedrons are found in Westmoreland, New Hampshire. |
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Picture Icon Links |
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Picture Links | 1. Three
transparent Fluorite specimens 2. Colerless cubes on matrix 3. Yellow Fluorite cubes 4. Dark purple Fluorite mass 5. Three individual octahedral crystals 6. Purple Fluorite in Calcite 7. Multicolored cleavage fragment 8. Pale blue Fluorite cube 9. Black Fluorite |
