# Gahnite

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> Markdown URL: https://mediated.wiki/source/Gahnite.md
> Source: https://en.wikipedia.org/wiki/Gahnite
> Source revision: 1136670336
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{{Infobox mineral
| name        = Gahnite
| category    = [Oxide minerals](/source/Oxide_minerals) <br />[Spinel group](/source/Spinel_group) <br />Spinel structural group
| boxwidth    =
| image       = Gahnite.jpg
| imagesize   = 260px
| caption     =
| formula     = ZnAl<sub>2</sub>O<sub>4</sub>
| IMAsymbol   = Ghn<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>
| strunz      = 4.BB.05
| system      = [Cubic](/source/Isometric_crystal_system)
| class       = Hexoctahedral (m{{overline|3}}m) <br/>[H-M symbol](/source/H-M_symbol): (4/m {{overline|3}} 2/m)
| symmetry    = ''Fd''{{overline|3}}m
| color       = Dark green, bluish green, blue to indigo, yellow to brown
| habit       = Typically octahedra, rarely as dodecahedra also massive to granular
| twinning    = Common on [111] produces striations
| cleavage    = Indistinct parting on [111]
| fracture    = Conchoidal, uneven
| mohs        = 7.5–8.0
| luster      = Vitreous
| refractive  = n = 1.79–1.80
| opticalprop = Isotropic
| birefringence =
| pleochroism =
| streak      = Grey
| gravity     = 4.38–4.60
| melt        =
| fusibility  =
| diagnostic  =
| solubility  =
| diaphaneity = Translucent to nearly opaque
| other       =
| references  = <ref name=Handbook>{{cite web |last1=Anthony |first1=John W. |last2=Bideaux |first2=Richard A. |last3=Bladh |first3=Kenneth W. |last4=Nichols |first4=Monte C. |title=Gahnite |url=http://www.handbookofmineralogy.org/pdfs/gahnite.pdf |website=Handbook of Mineralogy |publisher=Mineral Data Publishing |access-date=14 March 2022 |date=2005}}</ref><ref name=Mindat>{{mindat|id=1632|title=Gahnite}}</ref><ref name=Webmineral>http://webmineral.com/data/Gahnite.shtml Webmineral</ref>
}}

'''Gahnite''', ZnAl<sub>2</sub>O<sub>4</sub>, is a rare mineral belonging to the [spinel](/source/spinel) group. It forms octahedral crystals which may be green, blue, yellow, brown or grey. It often forms as an alteration product of [sphalerite](/source/sphalerite) in altered massive sulphide deposits such as at [Broken Hill](/source/Broken_Hill), Australia. Other occurrences include [Falun](/source/Falun), [Sweden](/source/Sweden) where it is found in [pegmatites](/source/pegmatites) and [skarn](/source/skarn)s; and, in the [United States](/source/United_States), [Charlemont, Massachusetts](/source/Charlemont%2C_Massachusetts); [Spruce Pine, North Carolina](/source/Spruce_Pine%2C_North_Carolina); [White Picacho district, Arizona](/source/White_Picacho_district%2C_Arizona); [Topsham, Maine](/source/Topsham%2C_Maine); and [Franklin, New Jersey](/source/Franklin%2C_New_Jersey).<ref name=Handbook/><ref name=Mindat/>

It was first described in 1807 for an occurrence in the Falu mine, Falun, Dalarna, Sweden, and named after the Swedish chemist, [Johan Gottlieb Gahn](/source/Johan_Gottlieb_Gahn) (1745–1818), the discoverer of the element [manganese](/source/manganese).<ref name=Mindat/><ref name=Webmineral/> It is sometimes called ''zinc spinel''.

==See also==
* [List of minerals named after people](/source/List_of_minerals_named_after_people)

==References==
{{Reflist}}

{{Commons category}}

Category:Zinc minerals
Category:Aluminium minerals
Category:Spinel group
Category:Cubic minerals
Category:Minerals in space group 227
Category:Minerals described in 1807

{{Oxide-mineral-stub}}

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Adapted from the Wikipedia article [Gahnite](https://en.wikipedia.org/wiki/Gahnite) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Gahnite?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.