Chromite 649259 224666187 2008-07-09T21:48:58Z Muro Bot 5849026 robot Adding: [[eu:Kromita]] {{Infobox mineral | name = Chromite | category = | boxwidth = | boxbgcolor = | image = ChromiteUSGOV.jpg | caption = | formula = [[iron]] [[magnesium]] [[chromium]] [[oxide]]: <!-- -->(Fe, Mg)Cr<sub>2</sub>O<sub>4</sub> | molweight = | color = Black to brownish black | habit = Octahedral rare; massive to granular | system = [[Cubic (crystal system)|Isometric]]; hexoctahedral | twinning = | cleavage = absent | fracture = Conchoidal | mohs = 5.5 | luster = Submetallic | refractive = Subtranslucent to opaque | opticalprop = | birefringence = | pleochroism = | streak = Dark brown | gravity = 4.5 - 4.8 | melt = | fusibility = Infusible | diagnostic = | solubility = | diaphaneity = | other = Weakly magnetic | var1 = Magnesiochromite | var1text = }} '''Chromite''', iron magnesium chromium oxide: (Fe, Mg)Cr<sub>2</sub>O<sub>4</sub>, is an [[oxide]] [[mineral]] belonging to the [[spinel]] group. [[Magnesium]] is always present in variable amounts, also [[aluminium]] and [[iron]] substitute for [[chromium]]. Chromite is found in [[peridotite]] and other layered [[ultramafic]] intrusive rocks and also found in metamorphic rocks such as serpentinites. [[Ore]] deposits of chromite form as early magmatic differentiates. It is commonly associated with [[olivine]], [[magnetite]], [[serpentine]], and [[corundum]]. The vast [[Bushveld igneous complex]] of [[South Africa]] is a large layered [[mafic]] to [[ultramafic]] igneous body with some layers consisting of 90% chromite making the rare rock type, chromitite. Chromite is also used as a [[refractory]] material. [[Image:Chromit, Albania.jpg|thumb|left|200px|Chromite from [[Albania]]]] The only ore of chromium is the mineral chromite. In the western hemisphere, chromite ore is produced only in Brazil and Cuba; By comparison, about 80% of world production of chromite comes from India, Iran, Pakistan, Oman, Zimbabwe, Turkey and Southern Africa. Southern Africa itself produces about half of this. Chromite is mined from the ultramafic rocks in the Zhob District of [[Balochistan (Pakistan)|Balochistan]]. Most of the chromite is of metallurgical grade with Cr<sub>2</sub>O<sub>3</sub> averaging 46% and a chrome to iron ratio of 3:1. == References == * Dana's Manual of Mineralogy ISBN 0-471-03288-3 * Guilbert, John M., and Park, Charles F., Jr. (1986) The Geology of Ore Deposits, Freeman, ISBN 0-7167-1456-6 * [http://mineral.galleries.com/minerals/oxides/chromite/chromite.htm Mineral Galleries: Chromite] *[http://webmineral.com/data/Chromite.shtml Webmineral.com] *[http://www.minerals.net/mineral/oxides/chromite/chromite.htm Minerals.net] *[http://minerals.usgs.gov/minerals/pubs/country/1998/9324098.pdf USGS info.] [[Category:Magnesium minerals]] [[Category:Iron minerals]] [[Category:Chromium minerals]] [[Category:Oxide minerals]] [[Category:Refractory materials]] {{mineral-stub}} [[cs:Chromit]] [[de:Chromit]] [[es:Cromita]] [[eo:Kromito]] [[eu:Kromita]] [[fr:Chromite]] [[it:Cromite]] [[he:כרומיט]] [[lt:Chromitas]] [[hu:Kromit]] [[nl:Chromiet]] [[ja:クロム鉄鉱]] [[nds:Chromit]] [[pl:Chromit]] [[pt:Cromita]] [[ro:Cromit]] [[fi:Kromiitti]] [[sv:Kromit]] [[uk:Хроміт]] [[zh:铬铁矿]]