Walfordite

{{Short description|Tellurite mineral}} {{Infobox mineral | name = Walfordite | image = Walfordite - Tambo Mine, Elqui Province, Coquimbo Region, Chile2.jpg | alt = | caption = Walfordite from Tambo Mine, Elqui Province, Chile | category = Tellurite minerals | formula = Fe³⁺,Te⁶⁺Te⁴⁺₃O₈ | IMAsymbol = wfd<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.JK.05 | dana = | system = Isometric | symmetry = I2, Ia3 | unit cell = a = 11.011&nbsp;Å ; Z&nbsp;=&nbsp;8 | color = | colour = Orange | habit = Microscopic cubic crystals | twinning = | cleavage = None | fracture = | tenacity = Brittle | mohs = | luster = Adamantine | streak = Orange-yellow | diaphaneity = Opaque | gravity = 5.841 (calculated) | density = | polish = | opticalprop = Isotropic | refractive = n = 2.23 | birefringence = | pleochroism = | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = | prop1 = | prop1text = | references = <ref name=HBM>[https://rruff.info/doclib/hom/walfordite.pdf Walfordite in the Handbook of Mineralogy]</ref><ref name=Mindat>[http://www.mindat.org/show.php?id=7360 Walfordite on Mindat.org]</ref><ref name=Webmin>[https://www.webmineral.com/data/Walfordite.shtml#.Us6pFNLjVVY Walfordite data on Webmineral]</ref> }}

'''Walfordite''' is a very rare tellurite mineral that was discovered in Chile in 1999.<ref name=Back1999> {{Cite journal |url=https://rruff.geo.arizona.edu/doclib/cm/vol37/CM37_1261.pdf |title=Walfordite, a New Tellurite Species from the Wendy Open Pit, El Indio - Tambo Mining Property, Chile |journal=The Canadian Mineralogist |volume=37|pages=1261–1268|year=1999 |first1=Malcolm E.|last1=Back |first2=Joel D.|last2=Grice |first3=Robert A.|last3=Gault |first4=Alan J.|last4=Criddle |first5=Joseph A.|last5=Mandarino}}</ref> The mineral is described as orange with orange-yellow streak, and is determined to have a chemical formula of Fe³⁺,Te⁶⁺Te⁴⁺₃O₈<ref name=HBM/> with minor titanium and magnesium substitution resulting in an approximate empirical formula of (Fe³⁺,Te⁶⁺,Ti⁴⁺,Mg)(Te⁴⁺)₃O₈.<ref name=Back1999/>

==Occurrence== The only reported occurrence<ref name=Mindat/> is in the Wendy open pit, El Indio-Tambo mining district of the Coquimbo Region, northern Chile where it occurs in oxidized breccia associated with a tellurium-bearing gold deposit. Associated minerals include: alunite, rodalquilarite, native gold, emmonsite, jarosite and pyrite. The mineral was named for mine geologist Phillip Walford (1945— ) who first noted the mineral.<Ref name=HBM/>

==See also== *El Indio Gold Belt. Tambo is adjacent to the El Indio mine. Both are now closed.

==References== {{Reflist}}

Category:Tellurium minerals Category:Oxide minerals Category:Cubic minerals Category:Minerals in space group 206 Category:Minerals described in 1999

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