{{Short description|Spinel mineral}} {{Infobox mineral |name=Nichromite |image=Nichromite.jpg| category = Spinel group | formula = {{chem2|(Ni,Co,Fe)(Cr,Fe,Al)2O4}} | strunz = 4.BB.05 | system = Isometric | class = Hexoctahedral (m{{overline|3}}m) <br/>H-M symbol: (4/m {{overline|3}} 2/m) | symmetry = ''Fd''{{overline|3}}m | unit cell = a = 8.32 Å; V = 573.86 Å<sup>3</sup>; Z = 8 | color = Dark green, black | habit = Granular, anhedral to subhedral | mohs = 6-{{frac|6|1|2}} | fracture = Conchoidal | luster = Metallic | refractive = | opticalprop = Isotropic | pleochroism = | streak = Greyish green | gravity = 5.10 |diaphaneity = Opaque |references=<ref name=Mindat>[http://www.mindat.org/min-2894.html Nichromite on Mindat.org]</ref><ref name=Webmin>[http://webmineral.com/data/Nichromite.shtml Nichromite on Webmineral]</ref><ref>Sawaokaa,A.,Saitoa,S.,Inoueb,K. and Asadab,T. (1971)Effect of high pressure on the lattice constants of chromites having the spinel structure. Materials Research Bulletin, 6, 97-101.</ref><ref name=Cabri>Cabri, L. J., Chao G.Y., Pabst, Adolf, Fleischer, Michael. (1980) New Mineral Names. American Mineralogist, 65, 811.</ref> }} '''Nichromite''' {{chem2|(Ni,Co,Fe)(Cr,Fe,Al)2O4}}<ref name=Mindat/> is a black cubic metallic mineral and member of the spinel group.<ref>[http://glossary.agiweb.org/dbtw-wpd/exec/dbtwpub.dll Glossary of Geology]</ref> Nichromite was originally reported from the Bon Accord nickel deposit in Barberton District, South Africa.<ref name=Mindat/> Occurring naturally in a nickel deposit, nichromite is named for chromite with dominant nickel.<ref name=Webmin/>
The atomic arrangement of the spinel group is a commonly studied structure and characteristically has four closely packed oxygen atoms. The nickel atoms are organized corresponding to a "normal" spinel arrangement.<ref>Wyckoff, R.W.G. (1965) Crystal Structures (Second Edition). 75-86 p. University of Arizona, Tucson, Arizona.</ref>
The mineral has only been found in the Bon Accord Nickel Deposit in South Africa where it is formed by replacing chromite and rimmed by trevorite.<ref name=Cabri/>
==References== {{Reflist}}
Category:Spinel group Category:Cubic minerals Category:Minerals in space group 227
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