Carnallite: Difference between revisions
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| references = <ref name=Webmin>[http://www.webmineral.com/data/Carnallite.shtml Webmineral data]</ref><ref name=Handbook>[http://rruff.geo.arizona.edu/doclib/hom/carnallite.pdf Handbook of Mineralogy]</ref><ref name=mindat>[http://www.mindat.org/min-906.html Carnallite on Mindat]</ref> |
| references = <ref name=Webmin>[http://www.webmineral.com/data/Carnallite.shtml Webmineral data]</ref><ref name=Handbook>[http://rruff.geo.arizona.edu/doclib/hom/carnallite.pdf Handbook of Mineralogy]</ref><ref name=mindat>[http://www.mindat.org/min-906.html Carnallite on Mindat]</ref> |
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'''Carnallite''' is an [[evaporite]] mineral, a hydrated [[potassium]] [[magnesium]] [[chloride]] with formula: [[potassium|K]][[magnesium|Mg]][[chlorine|Cl]]<sub>3</sub>·6([[water|H<sub>2</sub>O]]). It is variably colored yellow to white, reddish, and sometimes colorless or blue. It is usually massive to fibrous with rare pseudohexagonal [[orthorhombic]] crystals. The mineral is [[deliquescent]] (absorbs moisture from the surrounding air) and specimens must be stored in an airtight container. |
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Carnallite occurs with a sequence of potassium and magnesium evaporite minerals [[sylvite]], [[kainite]], [[picromerite]], [[polyhalite]] and [[kieserite]]. Carnallite is a somewhat rare double chloride mineral which only forms under a specific environmental conditions in an evaporating sea or [[sedimentary basin]]. It is mined for both potassium and magnesium and occurs in the evaporite deposits of [[Carlsbad, New Mexico]]; the [[Paradox Basin]] in [[Colorado]] and [[Utah]]; [[Stassfurt]], [[Germany]]; the [[Perm Basin]], [[Russia]]; and the [[Williston Basin]] in [[Saskatchewan, Canada]]. These deposits date from the [[Devonian]] through the [[Permian]] Periods. In contrast, both [[Israel]] and [[Jordan]] produce [[potash]] from the [[Dead Sea]] by using evaporation pans to further concentrate the brine until carnallite precipitates, dredging the carnallite from the pans, and processing to remove the [[magnesium chloride]] from the [[potassium chloride]].<ref name=mindat/> |
Carnallite occurs with a sequence of potassium and magnesium evaporite minerals [[sylvite]], [[kainite]], [[picromerite]], [[polyhalite]] and [[kieserite]]. Carnallite is a somewhat rare double chloride mineral which only forms under a specific environmental conditions in an evaporating sea or [[sedimentary basin]]. It is mined for both potassium and magnesium and occurs in the evaporite deposits of [[Carlsbad, New Mexico]]; the [[Paradox Basin]] in [[Colorado]] and [[Utah]]; [[Stassfurt]], [[Germany]]; the [[Perm Basin]], [[Russia]]; and the [[Williston Basin]] in [[Saskatchewan, Canada]]. These deposits date from the [[Devonian]] through the [[Permian]] Periods. In contrast, both [[Israel]] and [[Jordan]] produce [[potash]] from the [[Dead Sea]] by using evaporation pans to further concentrate the brine until carnallite precipitates, dredging the carnallite from the pans, and processing to remove the [[magnesium chloride]] from the [[potassium chloride]].<ref name=mindat/> |
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*[[List of minerals]] |
*[[List of minerals]] |
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*[[List of minerals named after people]] |
*[[List of minerals named after people]] |
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carnalite is not a ore of magnesium |
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==References== |
==References== |
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{{reflist}} |
{{reflist}} |
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Revision as of 11:10, 2 June 2010
| Carnallite | |
|---|---|
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| General | |
| Category | Halide mineral |
| Formula (repeating unit) | KMgCl3·6(H2O) |
| Crystal system | Orthorhombic, (2/m 2/m 2/m), space group: Pcna |
| Identification | |
| Formula mass | 277.85 |
| Color | Blue, colorless, yellow, white, red |
| Crystal habit | Fibrous |
| Fracture | Conchoidal |
| Mohs scale hardness | 2.5 |
| Luster | Greasy |
| Streak | White |
| Diaphaneity | Transparent to translucent |
| Specific gravity | 1.6 |
| Optical properties | Biaxial (+) |
| Refractive index | nα = 1.467 nβ = 1.476 nγ = 1.494 |
| Birefringence | 0.0270 |
| 2V angle | 70 |
| Other characteristics | Non-fluorescent |
| References | [1][2][3] |
Carnallite is an evaporite mineral, a hydrated potassium magnesium chloride with formula: KMgCl3·6(H2O). It is variably colored yellow to white, reddish, and sometimes colorless or blue. It is usually massive to fibrous with rare pseudohexagonal orthorhombic crystals. The mineral is deliquescent (absorbs moisture from the surrounding air) and specimens must be stored in an airtight container.
Carnallite occurs with a sequence of potassium and magnesium evaporite minerals sylvite, kainite, picromerite, polyhalite and kieserite. Carnallite is a somewhat rare double chloride mineral which only forms under a specific environmental conditions in an evaporating sea or sedimentary basin. It is mined for both potassium and magnesium and occurs in the evaporite deposits of Carlsbad, New Mexico; the Paradox Basin in Colorado and Utah; Stassfurt, Germany; the Perm Basin, Russia; and the Williston Basin in Saskatchewan, Canada. These deposits date from the Devonian through the Permian Periods. In contrast, both Israel and Jordan produce potash from the Dead Sea by using evaporation pans to further concentrate the brine until carnallite precipitates, dredging the carnallite from the pans, and processing to remove the magnesium chloride from the potassium chloride.[3]
Carnallite was first described in 1856 from its type location of Stassfurt Deposit, Saxony-Anhalt, Germany. It was named for the Prussian mining engineer, Rudolf von Carnall (1804–1874).[3]
See also
References