{{Short description|Copper iron sulfide mineral}} {{Infobox mineral | name = Mooihoekite | category = Sulfide mineral | boxwidth = | boxbgcolor = | image = | imagesize = | caption = | formula = Cu<sub>9</sub>Fe<sub>9</sub>S<sub>16</sub> | IMAsymbol = Mho<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 = 1,587.59 g/mol | strunz = 2.CB.10b | system = Tetragonal | class = Scalenohedral ({{overline|4}}2m) <br/>H-M symbol: ({{overline|4}} 2m) | symmetry = ''P''{{overline|4}}2m | unit cell = a = 10.58 Å, c = 5.38 Å; <br/>Volume = 602.22 Å<sup>3</sup>; Z = 1 | color = Pale yellow. Tarnishes to pinkish brown and purple | habit = Granular - Generally occurs as anhedral to subhedral crystals in matrix | twinning = | cleavage = | fracture = | tenacity = | mohs = 4 | luster = Metallic | refractive = | opticalprop = Weakly anisotropic | birefringence = | pleochroism = | streak = Black | gravity = 4.36 | density = | melt = | fusibility = | diagnostic = | solubility = | diaphaneity = Opaque | other = | references = <ref>[https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Mooihoekite Mineralienatlas]</ref><ref name = amer>Cabri, L.J. and Hall, S.R. (1972) Mooihoekite and Haycockite, Two New Copper-Iron Sulfides, and Their Relationship to Chalcopyrite and Talnakhite. American Mineralogist, 57, 689-708.</ref><ref name = acta>Hall, S.R. and Rowland, J.F. (1973) The Crystal Structure of Synthetic Mooihoekite. Acta Crystallographica, 29, 2365-2372.</ref><ref name=Webmin>[http://webmineral.com/data/Mooihoekite.shtml Webmineral data]</ref><ref name=Mindat>[http://www.mindat.org/min-2772.html Mindat.org]</ref><ref name=HBM>[http://rruff.geo.arizona.edu/doclib/hom/mooihoekite.pdf Handbook of Mineralogy]</ref> }}
'''Mooihoekite''' is a copper iron sulfide mineral with chemical formula of Cu<sub>9</sub>Fe<sub>9</sub>S<sub>16</sub>. The mineral was discovered in 1972 and received its name from its discovery area, the Mooihoek mine in Transvaal, South Africa.<ref name=Webmin/>
==Crystal structure and optical properties== Mooihoekite crystallizes in the tetragonal crystal system. It has a short optical c-axis that is perpendicular to two longer a-axes of equal length. For Mooihoekite, the c-axis is a 4-fold rotoinversion axis.<ref name="amer"/>
Mooihoekite is an opaque mineral which shows weak anisotropism in polished section under reflected light microscopy. It goes slightly extinct every 90°.<ref name="amer"/>
==Occurrence== It is found in massive sulfide from pipe-shaped dunite pegmatite in the norite zone of the Bushveld igneous complex in South Africa. It has also been found in troctolite from the basal Duluth gabbro in Minnesota, US; in the Talnakh area, Norilsk region, western Siberia; at Krzemianka, Poland; in the Malanjkhand copper-molybdenum deposit, Madhya Pradesh, India; and the Stillwater igneous complex in Montana, US.<ref name=Mindat/><ref name=HBM/>
Mooihoekite occurs in association with haycockite, magnetite, troilite, cuprian pentlandite, mackinawite, sphalerite, and moncheite in the Mooihoek mine and with haycockite, native copper, troilite, pentlandite, cubanite and magnetite in the Duluth complex.<ref name=HBM/>
==Uses== Mooihoekite is a rare mineral that is mostly used for research purposes. It has similar properties to chalcopyrite CuFeS<sub>2</sub>, making it helpful in the study of ore deposits and the study of the central portion of the Cu-Fe-S phase system.<ref name="amer"/> Mooihoekite, chalcopyrite, talnakhite, and haycockite all play key roles in the study of ore genesis and beneficiation.
== References == {{Reflist}}
Category:Copper minerals Category:Iron minerals Category:Sulfide minerals Category:Tetragonal minerals Category:Minerals in space group 111 Category:Minerals described in 1972