Editing Creedite

{{Infobox mineral
| name    = Creedite
| category  = [[Halide mineral]]
| boxwidth  = 
| boxbgcolor = 
| image    =  Creedite 3 photo fond.jpg
| imagesize  = 260px
| caption   = Creedite, [[Santa Eulalia District]], [[Aquiles Serdán, Chihuahua|Municipio de Aquiles Serdán]], [[Chihuahua (state)|Chihuahua]], Mexico
| formula   = Ca<sub>3</sub>Al<sub>2</sub>(SO<sub>4</sub>)(F,OH)<sub>10</sub>•2(H<sub>2</sub>O)
| IMAsymbol=Cee<ref>{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|journal=Mineralogical Magazine|volume=85|issue=3|pages=291–320|doi=10.1180/mgm.2021.43|bibcode=2021MinM...85..291W|s2cid=235729616|doi-access=free}}</ref> 
| molweight  = 
| strunz    = 3.CG.15
| system   = [[Monoclinic]]
| class   = Prismatic (2/m) <br/><small>(same [[H-M symbol]])</small>
| symmetry   = ''C2/c''
| unit cell  = a = 13.91&nbsp;Å, b = 8.58&nbsp;Å, <br/>c = 10&nbsp;Å; β = 94.4°; Z&nbsp;=&nbsp;4
| color    = Colorless, white, violet, orange
| habit    = Generally appears as anhedral to subhedral in matrix; bladelike prismatic and radial, drusy to granular aggregates
| cleavage  = Perfect on {100}
| mohs = 3.5 - 4
| luster = Vitreous
| streak   = White
| density   = 
| fracture  = Conchoidal
| tenacity  = Brittle
| opticalprop = Biaxial (-)
| refractive = n<sub>α</sub> = 1.461 n<sub>β</sub> = 1.478 n<sub>γ</sub> = 1.485
| birefringence = δ = 0.024
| dispersion = r > v strong
| pleochroism = 
| 2V          = 65°
| fluorescence= 
| absorption =
| gravity   = 2.71
| fusibility = 
| diagnostic = 
| diaphaneity = Transparent to translucent
| other    = 
| references = <ref name=Mindat>http://www.mindat.org/min-1151.html Mindat</ref><ref name=Webmin>http://www.webmineral.com/data/Creedite.shtml Webmineral</ref><ref name=Handbook>http://rruff.geo.arizona.edu/doclib/hom/creedite.pdf Handbook of Mineralogy</ref>
}}

'''Creedite''' is a [[calcium]] [[aluminium]] [[sulfate]] [[fluoride|fluoro]] [[hydroxide]] [[mineral]] with formula: Ca<sub>3</sub>Al<sub>2</sub>SO<sub>4</sub>(F,OH)<sub>10</sub>·2(H<sub>2</sub>O). Creedite forms colorless to white to purple [[monoclinic]] prismatic crystals. It often occurs as acicular radiating sprays of fine prisms. It is translucent to transparent with [[index of refraction|indices of refraction]] of n<sub>α</sub> = 1.461 n<sub>β</sub> = 1.478 n<sub>γ</sub> = 1.485. It has a [[Mohs hardness]] of 3.5 to 4 and a [[specific gravity]] of 2.7.

Creedite was first described in 1916 from the Creede Quadrangle in [[Mineral County, Colorado]]. It is a product of intense [[oxidation]] of [[ore]] deposits.

==Occurrence==
[[File:Creedite-280276.jpg|thumb|left|'''Creedite''', Qinglong Sb-Au deposit, [[Qinglong County, Guizhou|Qinglong County]],  [[Guizhou Province]], China. Overall (size: 3.4 x 3.0 x 1.3&nbsp;cm)]]
Creedite is a rare hydroxylhalide mineral. Creedite usually forms from the [[oxidation]] of [[fluorite]] ore deposits. Creedite was named after the location where it was discovered in 1916 in the Colorado Fluorspar Co. Mine at Wagon Wheel Gap, located at Creede Quadrangle, [[Mineral County, Colorado]].<ref name=Mindat/>

It was later found in other fluorite veins near [[Tonopah, Nevada|Tonopah]], [[Nye County, Nevada]]; in the Grand Reef mine, [[Graham County, Arizona]]; in the Darwin district, [[Inyo County, California]]. It also occurs in the Potosi and other mines of [[Santa Eulalia, Chihuahua|Santa Eulalia]], [[Chihuahua (state)|Chihuahua]], [[Mexico]]. It is also found in [[La Paz]], [[Bolivia]]; [[Pamir Mountains]], [[Tajikistan]] and [[Dzhezkazgan]], [[Kazakhstan]].<ref name=Handbook/>

==Geologic association==

[[File:Creedite 3.jpg|thumb|Creedite, Navidad Mine, [[Rodeo Municipality|Rodeo]], [[Durango]], [[Mexico]]]]
Creedite typically occurs with low-grade [[metamorphic rock]]s on a fluorite – calcite – quartz matrix or on a sulfide-matrix with its oxidized products. Creedite most commonly found in the form of creedite – carbonate – [[cyanotrichite]] – [[woodwardite]] – [[spangolite]] – [[kaolinite]] association. The other less common creedite association is creedite – [[limonite]] – kaolinite – [[hemimorphite]] – [[smithsonite]] – [[hydrozincite]] – [[aurichalcite]]. Creedite also occurs in [[skarn]] formation which usually has association with [[Sulfide mineral|sulfides]], spangolite, [[brochantite]], [[linarite]], limonite, [[cuprite]], [[Wad (mineral)|wad]] and kaolinite. In general, creedite usually found as two to three millimeters radial [[Aggregate (geology)|aggregate]]s and less commonly as a single prismatic crystals up to one millimeters long.<ref>Frau, F.; Rizzo, R.; Sabelli, C., ''Creedite from Sardinia, Italy: the first European Occurrence,'' Neues Jahrbuch für Mineralogie-Monashefte, pp.495–504, Nov. 1998.</ref>

==Structure==
Creedite structural composition study was conducted by utilizing 1390 Philips diffractometer with Fe – filtered CoK radiation ([[Wavelength|λ]]=1.79021[[Angstrom|Å]]), 10–90° 2θ range, peak-height relative intensities. It was concluded that the creedite falls into monoclinic crystal system (2/m) that has space group of C2/c. It was also found that creedite has basal reflections of (2 0 0) and (4 0 0) that are enhanced due to preferred orientation which concur with Michael Fleischer's orientation.<ref>Giuseppetti, G; Tadini, C., Structure Analysis and refinement of Bolivian Creedite, Ca3Al2F8(OH)2(SO4)*2(H2O), Neues Jahrbuch für Mineralogie-Monashefte, pp.69–78, 1983</ref>

==References==
{{Reflist}}
*Kiselva, I. A.; Ogorodova, L.P.; Mel'Chalkova, L.V.; Getmanskaya, T.I., Enthalpy of Formation of Creedite Ca3Al2F8.25(OH) (1.75)(SO4) Center dot 2H(2) O, Geochemistry International, pp.&nbsp;1026–1030, OCT 2002.
*Frau, F.; Rizzo, R.; Sabelli, C., Creedite from Sardinia, Italy: the first European Occurrence, Neues Jahrbuch für Mineralogie-Monashefte, pp.&nbsp;495–504, NOV 1998.
*Giuseppetti, G; Tadini, C., Structure Analysis and refinement of Bolivian Creedite, Ca3Al2F8(OH)2(SO4)*2(H2O), Neues Jahrbuch für Mineralogie-Monashefte, pp.&nbsp;69–78, 1983.
*Fleischer, M, Probable Identity of Belyankite With Creedite, U.S. Geological Survey, {{Nowrap|March 12}}, 1992.
*K, Robert B., Creedite: Cresson Mine, Cripple Creek Teller County, Colorado. Rocks & Minerals, pp422–427, OCT 2008.
*Foshag, W. F., (1932) Creedite from Nevada: Am. Mineral., 17, 75–77.

==External links==
*[https://web.archive.org/web/20051105220014/http://mineral.galleries.com/minerals/sulfates/creedite/creedite.htm Mineral galleries]

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[[Category:Calcium minerals]]
[[Category:Aluminium minerals]]
[[Category:Fluorine minerals]]
[[Category:Monoclinic minerals]]
[[Category:Minerals in space group 15]]
[[Category:Minerals described in 1916]]