View source for Fukuchilite

{{Expand German}}{{Infobox mineral
| name        = Fukuchilite
| image       = Fukuchilite displayed at Mining Museum of Akita University.jpg
| alt         = sample of fukuchilite 
| caption     = Fukuchilite 
| category    = [[Sulfide mineral]]
| formula     = Cu<sub>3</sub>FeS<sub>8</sub>
| IMAsymbol   = Fuk<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      = 2.EB.05a
| dana        = 
| system      = [[Cubic crystal system|Cubic]]
| class       = Diploidal (m{{overline|3}}) <br/>[[H-M symbol]]: (2/m {{overline|3}})
| symmetry    = ''Pa3''
| unit cell   = a = 5.58&nbsp;Å: Z&nbsp;=&nbsp;1
| color       = Dark brownish gray; pinkish brown in polished section
| habit       = As intergrowths with [[pyrite]] and [[covellite]], grains less than 1 μm
| twinning    = 
| cleavage    = 
| fracture    = 
| tenacity    = 
| mohs        = 4 - 6
| luster      = Submetallic
| streak      = 
| diaphaneity = Opaque
| gravity     = 4.86
| density     =  
| polish      = 
| opticalprop = Isotropic
| refractive  = 
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| 2V          = 
| dispersion  = 
| extinction  = 
| length fast/slow =
| fluorescence = 
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| melt        = 
| fusibility  = 
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| solubility  = 
| impurities  = 
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| other       = 
| prop1       = 
| prop1text   = 
| references  = <ref name=Mindat>[http://www.mindat.org/min-1620.html Fukuchilite on Mindat.org]</ref><ref name=HBM>[http://rruff.info/doclib/hom/fukuchilite.pdf Fukuchilite in the Handbook of Mineralogy]</ref><ref>[http://www.webmineral.com/data/Fukuchilite.shtml Fukuchilite data on Webmineral]</ref>
}}

'''Fukuchilite''', {{chem|[[copper|Cu]]|3|[[iron|Fe]]|[[sulfur|S]]|8}}, is a [[copper]] [[iron]] [[sulfide]] named after the Japanese [[mineralogist]] Nobuyo Fukuchi (1877–1934), that occurs in ore bodies of [[gypsum]]-[[anhydrite]] at the intersection points of small masses of [[barite]], [[covellite]], [[gypsum]] and [[pyrite]], and is mostly found in the [[Hanawa mine]] in the [[Akita prefecture]] of [[Honshū]], [[Japan]] where it was first discovered in 1969.  It occurs in masses within the third geologic unit of the [[Volcanogenic massive sulfide ore deposit|Kuroko type deposits]] within the mine.

As a copper, iron sulfide, it is placed in the same group as [[bornite]] and [[chalcopyrite]], and most fukuchilite locations are found in relatively close proximity to these minerals. Fukuchilite was found to have a reflection color very similar to bornite and bright pinkish brown in air, while being a purplish brown in oil.  Also, it was found to have a reactivity lower than pyrite, but distinctly higher than bornite.<ref>Kajiwara, Yoshimichi. "Fukuchilite, Cu<sub>3</sub>FeS<sub>8</sub>, a New Mineral From the Hanawa Mine, Akita Prefecture, Japan." Mineralogical Journal 5 (1969): 400-415.</ref>  It has a [[Mohs hardness]] of 4–6, a [[specific gravity]] of 4.9, and a sub metallic luster, composed of 11.1% iron, 37.9% copper, and 51.00% of sulfur.<ref name=Bayliss>Bayliss, Peter. "Crystal Chemistry of Some Minerals Within the Pyrite Group." American Mineralogist 74 (1989): 1168-1176</ref>

It is in the [[isotropic]] [[cubic crystal system]] with symmetry: (2/m{{overline|3}}), space group P a3.  Much relating to the structure of the mineral is still under debate, and some believe that fukuchilite might actually be a form of [[villamaninite]] {{chem|([[copper|Cu]],[[nickel|Ni]],[[cobalt|Co]],[[iron|Fe]])|[[sulfur|S]]|2}},<ref>[http://webmineral.com/data/Villamaninite.shtml Villamaninite Mineral Data<!-- Bot generated title -->]</ref> but fukuchilite currently still holds its mineral status as there is currently not enough evidence to discredit an already accepted and titled mineral.<ref name=Bayliss/>

==References==
{{Reflist}}
{{Refbegin}}
* Terakado, Yasutaka, and Richard J. Walker. "Nd, Sr and Pb Isotopic and REE Geochemical Study of Some Miocene Submarine Hydrothermal Deposits (Kuroko Deposits) in Japan." Contributions to Mineralogy and Petrology 149 (2005): 388-399

{{Refend}}

[[Category:Copper minerals]]
[[Category:Iron minerals]]
[[Category:Pyrite group]]
[[Category:Cubic minerals]]
[[Category:Minerals in space group 205]]