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Fluorite

Fluorite crystals on display at the Cullen Hall of Gems and Minerals
General
Category mineral
Chemical formula calcium fluoride CaF2
Identification
Color Colorless, white, purple, blue, blue-green, green, yellow, brownish-yellow, pink or red
Crystal habit Occurs as well-formed coarse sized crystals also massive - granular
Crystal system Isometric 4/m bar 3 2/m
Cleavage [111] Perfect, [111] Perfect, [111] Perfect
Fracture Uneven
Mohs Scale hardness 4
Luster Vitreous
Refractive index 1. A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes Calcium (ˈkælsiəm is the Chemical element with the symbol Ca and Atomic number 20 Fluoride is the reduced form of Fluorine. Both organic and Inorganic compounds containing the element fluorine are considered fluorides In Mineralogy, shape and size give rise to descriptive terms applied to the typical appearance or habit of Crystals The many terms used by mineralogists A crystal system is a category of Space groups which characterize Symmetry of structures in three dimensions with Translational symmetry in three directions The cubic crystal system (or isometric) is a Crystal system where the Unit cell is in the shape of a Cube. Cleavage, in Mineralogy, is the tendency of crystalline materials to split along definite planes creating smooth surfaces of which there are several named types In the field of Mineralogy, fracture is a term used to describe the shape and texture of the surface formed when a Mineral is broken The Mohs scale of mineral hardness characterizes the scratch resistance of various Minerals through the ability of a harder material to scratch a softer material Lustre (or luster) is a description of the way light interacts with the surface of a Crystal, rock, or Mineral. The refractive index (or index of Refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves is reduced inside the medium 433–1. 435
Streak White
Specific gravity 3. The streak (also called powder color) of a Mineral is the Color of the powder produced when it is dragged across an unweathered surface Specific gravity is defined as the ratio of the Density of a given solid or liquid substance to the density of water at a specific temperature and pressure typically 18
Fusibility 3
Solubility Slightly in water
Other Characteristics sometimes phosphoresces when heated or scratched. Fusibility is the ease with which a material will Melt. Materials such as solder require a low melting point so that when heat is applied to a joint the solder will melt before Solubility is the characteristic Physical property referring to the ability of a given substance the Solute, to dissolve in a Solvent. Phosphorescence is a specific type of Photoluminescence related to fluorescence. Other varieties fluoresce

Fluorite (also called fluorspar) is a mineral composed of calcium fluoride, CaF2. Fluorescence is a Luminescence that is mostly found as an A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific Calcium fluoride (CaF2 is an insoluble Ionic compound of Calcium and Fluorine. Calcium (ˈkælsiəm is the Chemical element with the symbol Ca and Atomic number 20 Fluorine, fluorum meaning "to flow" is the Chemical element with the symbol F and Atomic number 9 It is an isometric mineral with a cubic habit, though octahedral and more complex isometric forms are not uncommon. The cubic crystal system (or isometric) is a Crystal system where the Unit cell is in the shape of a Cube. Cubic crystals up to 20 cm across have been found at Dalnegorsk, Russia. [1] Crystal twinning is common and adds complexity to the observed crystal habits. Crystal twinning occurs when two separate crystals share some of the same Crystal lattice points in a symmetrical manner In Materials science, a crystal is a Solid in which the constituent Atoms Molecules or Ions are packed in a regularly ordered repeating

The word fluorite is derived from the Latin root fluo, meaning "to flow" because the mineral has a relatively low melting point and was used as an important flux in smelting. Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. In the various subfields of Physics, there exist two common usages of the term flux, both with rigorous mathematical frameworks Fluorite gave its name to its constitutive element fluorine. Fluorine, fluorum meaning "to flow" is the Chemical element with the symbol F and Atomic number 9

Contents

Occurrence

Fluorite may occur as a vein deposit, especially with metallic minerals, where it often forms a part of the gangue (the worthless "host-rock" in which valuable minerals occur) and may be associated with galena, sphalerite, barite, quartz, and calcite. Tailings (also known as slimes, gangue, tailings pile, tails, leach residue, or slickens) are the materials left over Galena is the natural mineral form of Lead sulfide. It is the most important Lead Ore mineral Sphalerite (( Zn, Fe) S) is a Mineral that is the chief Ore of Zinc. Baryte ( Ba[[Sulfur S]] O 4 is a Mineral consisting of Barium sulfate. Quartz (from German) is the most abundant Mineral in the Earth 's Continental crust (although Feldspar is more common in Calcite is a carbonate mineral and the most stable polymorph of Calcium carbonate ( Ca[[carbon C]] O 3 It is a common mineral in deposits of hydrothermal origin and has been noted as a primary mineral in granites and other igneous rocks and as a common minor constituent of dolostone and limestone. Hydrothermal circulation in its most general sense is the circulation of hot water 'hydros' in the Greek meaning water and 'thermos' meaning heat Granite (ˈɡrænɪt is a common and widely occurring type of intrusive, Felsic, igneous rock. Igneous rocks (etymology from Latin ignis, fire are rocks formed by solidification of cooled Magma (molten rock Dolostone is a sedimentary Carbonate rock that contains a high percentage of the Mineral Dolomite. Limestone is a Sedimentary rock composed largely of the Mineral Calcite ( Calcium carbonate: CaCO3

Fluorite is a widely occurring mineral which is found in large deposits in many areas. Notable deposits occur in Germany, Austria, Switzerland, England, Norway, Mexico, and Ontario in Canada. Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe. Austria (Österreich ( officially the Republic of Austria (Republik Österreich Switzerland (English pronunciation; Schweiz Swiss German: Schwyz or Schwiiz Suisse Svizzera Svizra officially the Swiss Confederation England is a Country which is part of the United Kingdom. Its inhabitants account for more than 83% of the total UK population whilst its mainland Norway ( Norwegian: Norge ( Bokmål) or Noreg ( Nynorsk) officially the Kingdom of Norway, is a Constitutional The United Mexican States ( or commonly Mexico (ˈmɛksɪkoʊ () is a federal constitutional Republic in North America. Ontario (ɒnˈtɛrioʊ is a province located in the central part of Canada, the largest by population and second largest after Quebec Country to "Dominion of Canada" or "Canadian Federation" or anything else please read the Talk Page Large deposits also occur in Kenya in the Kerio Valley area within the Great Rift Valley. In the United States deposits are found in Missouri, Oklahoma, Illinois, Kentucky, Colorado, New Mexico, Arizona, Ohio, New Hampshire, New York, Alaska and Texas. The United States of America —commonly referred to as the Missouri ( or) is a state in the Midwestern region of the United States bordered by Iowa, Illinois, Kentucky, Tennessee Oklahoma ( is a state located in the South Central region of the United States of America. The State of Illinois ( roughly ill-i-NOY is a state of the United States of America, the 21st to be admitted to the Union. The Commonwealth of Kentucky ( is a state located in the East Central United States of America. The State of Colorado ( or chiefly by nonresidents) is a state located in the Rocky Mountain region of the United States of America. New Mexico ( is a state located in the southwestern region of the United States of America. The State of Arizona ( is a state located in the southwestern region of the United States. Ohio ( is a Midwestern state of the United States. As part of the Great Lakes region, Ohio has long been a cultural and geographical crossroads New Hampshire ( is a state in the New England region of the northeastern United States of America. New York ( is a state in the Mid-Atlantic and Northeastern regions of the United States and is the nation's third most populous Alaska ( Аляска Alyaska) is a state in the United States of America, in the northwest of the North American continent Texas ( is a state geographically located in the South Central United States and is also known as the Lone Star State. Illinois has historically been the largest producer of fluorite in the United States, however, the last of the mines closed in 1995. The State of Illinois ( roughly ill-i-NOY is a state of the United States of America, the 21st to be admitted to the Union. The Illinois general assembly passed a resolution in 1965 declaring fluorite as the official state mineral.

Blue John

Vein of Blue John in Treak Cliff Cavern
Vein of Blue John in Treak Cliff Cavern

One of the most famous of the older-known localities of fluorite is Castleton in Derbyshire, England, where, under the name of Derbyshire Blue John, purple-blue fluorite was extracted from several mines/caves, including the famous Blue John Cavern. This article is about the English village in Derbyshire For other uses see Castleton. History The area that is now Derbyshire was first visited probably briefly by humans 200000 years ago during the Aveley Interglacial as evidenced by a Middle England is a Country which is part of the United Kingdom. Its inhabitants account for more than 83% of the total UK population whilst its mainland The Blue John Cavern is one of the four Show caves in Castleton, Derbyshire, England. During the 19th century, this attractive fluorite was mined for its ornamental value. The name derives from French "bleu et jaune" (blue and yellow) characterising its color. Blue John is now scarce, and only a few hundred kilograms are mined each year for ornamental and lapidary use. A lapidary (the word means "concerned with stones" is an Artisan who practices the craft of working forming and finishing stone, Mineral, Mining still takes place in the nearby Treak Cliff Cavern. Recent deposits in China have produced fluorite with coloring and banding similar to the classic Blue John stone.

Fluorescence

Yellow fluorite (~ 4 cm in height)
Yellow fluorite (~ 4 cm in height)

Many samples of fluorite fluoresce under ultra-violet light, a property that takes its name from fluorite. Fluorescence is a Luminescence that is mostly found as an Ultraviolet ( UV) light is Electromagnetic radiation with a Wavelength shorter than that of Visible light, but longer than X-rays Many minerals, as well as other substances, fluoresce. Fluorescence involves the elevation of electron energy levels by quanta of ultra-violet light, followed by the progressive falling back of the electrons into their previous energy state, releasing quanta of visible light in the process. Fluorescence is a Luminescence that is mostly found as an Ultraviolet ( UV) light is Electromagnetic radiation with a Wavelength shorter than that of Visible light, but longer than X-rays In fluorite, the visible light emitted is most commonly blue, but red, purple, yellow, green and white also occur. The fluorescence of fluorite may be due to impurities such as yttrium or organic matter in the crystal lattice. Fluorescence is a Luminescence that is mostly found as an Yttrium (ˈɪtriəm is a Chemical element with symbol Y and Atomic number 39 It is not surprising, therefore, that the color of visible light emitted when a sample of fluorite is fluorescing appears dependent on where the original specimen was collected, different impurities having been included in the crystal lattice in different places. Neither do all fluorites fluoresce equally brightly, even from the same locality. Therefore ultra-violet light is not a reliable tool for the identification of specimens, nor for quantifying the mineral in mixtures. Ultraviolet ( UV) light is Electromagnetic radiation with a Wavelength shorter than that of Visible light, but longer than X-rays For example, among British fluorites, those from Northumberland, County Durham and Eastern Cumbria are the most consistently fluorescent, whereas fluorites from Yorkshire, Derbyshire and Cornwall, if they fluoresce at all, are generally only feebly fluorescent. Northumberland is a county in the North East of England. The non-metropolitan county of Northumberland borders Cumbria to the west Boundaries and divisions Cumbria is neighboured by Northumberland, County Durham, North Yorkshire, Lancashire, and the Lieutenancy Yorkshire is a historic county of Northern England and the largest in Great Britain. History The area that is now Derbyshire was first visited probably briefly by humans 200000 years ago during the Aveley Interglacial as evidenced by a Middle Cornwall ( Kernow ˈkɛɹnɔʊ is the most southwesterly county of England, on the Peninsula that lies to the west of the River Tamar

Fluorite also exhibits the property of thermoluminescence. Some mineral substances such as Fluorite store energy when exposed to Ultraviolet or other Ionising radiation.

Uses

Deep purple cubes of fluorite with galena (gray) and calcite (white) from Illinois, USA
Deep purple cubes of fluorite with galena (gray) and calcite (white) from Illinois, USA

There are three principal types of industrial use for fluorite, corresponding to different grades of purity. Metallurgical grade fluorite, the lowest of the three grades, has traditionally been used as a flux to lower the melting point of raw materials in steel production to aid the removal of impurities, and later in the production of aluminium. In Metallurgy, a flux is a chemical cleaning agent which facilitates Soldering, Brazing, and Welding by removing Oxidation from Steel is an Alloy consisting mostly of Iron, with a Carbon content between 0 WikipediaNaming Ceramic (intermediate) grade fluorite is used in the manufacture of opalescent glass, enamels and cooking utensils. Opalescence is a type of Dichroism seen in highly dispersed systems with little opacity. Glass in the common sense refers to a Hard, Brittle, transparent Solid, such as that used for Windows many In a discussion of Material science, enamel (or vitreous enamel or porcelain enamel in U The highest grade, acid grade fluorite, is used to make hydrofluoric acid by decomposing the fluorite with sulfuric acid. Hydrofluoric acid is a Solution of Hydrogen fluoride in Water. Sulfuric (or sulphuric acid, H 2 S[[oxygen O]]4 is a strong Mineral acid. Hydrofluoric acid is the primary feedstock for the manufacture of virtually all organic and inorganic fluorine-containing compounds, including fluoropolymers and perfluorocarbons, and is also used to etch glass. A fluoropolymer is a Polymer that contains atoms of Fluorine. Perfluorocarbons (PFCs are compounds derived from Hydrocarbons by replacement of Hydrogen Atoms by Fluorine atoms

Fluorite is used instead of glass in some high performance telescopes and camera lens elements. An optical telescope is a Telescope which is used to gather and focus light mainly from the visible part of the Electromagnetic spectrum A photographic lens (also known as objective lens or photographic objective) is an optical lens or assembly of lenses used in conjunction with Exposure tools for the semiconductor industry make use of fluorite optical elements for ultraviolet light at 157 nm wavelength. A semiconductor' is a Solid material that has Electrical conductivity in between a conductor and an insulator; it can vary over that Ultraviolet ( UV) light is Electromagnetic radiation with a Wavelength shorter than that of Visible light, but longer than X-rays In Physics wavelength is the distance between repeating units of a propagating Wave of a given Frequency. Fluorite has a uniquely high transparency at this wavelength. Fluorite has a very low dispersion so lenses made from it exhibit less chromatic aberration than those made of ordinary glass. In Optics, dispersion is the phenomenon in which the Phase velocity of a wave depends on its frequency In Optics, chromatic aberration is caused by a lens having a different Refractive index for different Wavelengths of Light In telescopes it allows crisp images of astronomical objects even at high power. Optical power ( dioptric power or refractive power) is the degree to which a lens or Mirror converges or diverges light Fluorite also has ornamental and lapidary uses. A lapidary (the word means "concerned with stones" is an Artisan who practices the craft of working forming and finishing stone, Mineral, The Canon camera company produces synthetic fluorite crystals which are used in their more expensive telephoto lenses.

Gallery

Pig carved in fluorite, 5 cm (2 inches) long

Mineral fluorite

Octahedral fluorite crystals from New Mexico, USA

Cleaved fluorite octahedra

The unit cell of fluorite's crystal structure

Fluorite with Iron Pyrite and Calcite blooms

See also

References

  1. ^ The Complete Encyclopedia of Minerals by P. Korbel and M. Novak

External links

Dictionary

fluorite

-noun

  1. a widely occuring mineral, (calcium fluoride), of various colours, used as a flux in steelmaking, and in the manufacture of glass, enamels and hydrofluoric acid
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