{{Infobox mineral | name = Kruťaite | boxwidth = | boxbgcolor = | image = Krutaite-91146.jpg | imagesize = | alt = | caption = Kruťaite from El Dragón mine, Antonio Quijarro Province, Potosí Department, Bolivia (picture width 2.5 mm). | category = Selenide minerals | formula = CuSe<sub>2</sub> | IMAsymbol = Krt<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 = | strunz = 2.EB.05a | dana = 2.12.1.8 | system = Cubic | class = Diploidal (m{{overline|3}}) <br/>H-M symbol: (2/m {{overline|3}}) | symmetry = Isometric <br/>Space group: ''P''a{{overline|3}} | unit cell = a = 6.056 Å, Z = 4 | color = Grey | colour = | habit = Often found as inclusions or octahedral crystals. | twinning = | cleavage = Good | fracture = | tenacity = | mohs = 4 | luster = Metallic | streak = Dark grey | diaphaneity = Opaque | gravity = 6.53 (calculated) | density = | polish = | opticalprop = | refractive = | birefringence = | pleochroism = | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence = None | absorption = | melt = | fusibility = | diagnostic = | solubility = Insoluble | impurities = Co, Ni, Fe, Hg | alteration = | other = | prop1 = | prop1text = | references = {{ref|1}}{{ref|2}}{{ref|3}} }}
'''Kruťaite''', simplified '''Krut'aite''' or '''krutaite''', is a rare mineral with the formula CuSe<sub>2</sub>. It crystallises in the cubic crystal system. It is part of the pyrite group, being composed of Cu<sup>2+</sup> ions and Se<sub>2</sub><sup>2−</sup> ions.<ref name=":0">{{Cite web|url=http://www.mindat.org/min-2279.html|title=Krut'aite: Krut'aite mineral information and data.|website=www.mindat.org|access-date=2016-09-16}}</ref> The mineral is most often found as a dark grey aggregate consisting of tiny crystals no more than a millimeter in size. The crystals are opaque in any size.
== Etymology== Kruťaite was first discovered in Petrovice in Okres Žďár nad Sázavou, Czech Republic and described in 1972 by Zdenek Johan, Paul Picot, Roland Pierrot and Milan Kvaček. It was named after Tomáš Kruťa (1906–1998), a Czech mineralogist and director of the mineralogical laboratory of the Moravian museum.<ref>{{Cite web |url=https://biblio.hiu.cas.cz/records/d22be0bd-fe69-4e33-b36a-2c0f89f7504d |title=Kruťa, Tomáš, 1906–1998 – |work=Bibliografie dějin Českých zemí |editor=KP-sys spol s r.o. |language=cs |access-date=2023-04-21}}</ref>
The International Mineralogical Association's rules on naming newly recognized minerals specify that a mineral name derived from a person's name should be capitalized and preserve any diacritics from the person's home language (or its romanization).{{citation needed|date=December 2024}} Thus, the older spellings ''krutaite'' and ''Krutaite'' are deprecated in favour of ''Kruťaite''. In Czech orthography, when a ''háček'' (◌̌) modifies a lowercase t, it has a reduced ''klička'' form (as ť) which looks like an apostrophe.
== Occurrence == Kruťaite forms through hydrothermal processes and is often associated with clausthalite, eskebornite, berzelianite, uraninite, hematite, ferroselite, bukovite, umangite, chalcopyrite and goethite.<ref>{{Cite web|url=http://www.handbookofmineralogy.com/pdfs/krutaite.pdf|title=Handbook of mineralogy|access-date=2016-09-16|archive-date=2020-09-23|archive-url=https://web.archive.org/web/20200923154958/http://www.handbookofmineralogy.com/pdfs/krutaite.pdf|url-status=dead}}</ref> It forms a solid solution series with trogtalite.<ref name=":0" />
It was first identified in Petrovice, Okres Žďár nad Sázavou, Czech Republic, which is the only known locality in the Czech republic for the mineral, but it has since been identified in other places in the world.
Notable is the El Dragón Mine, Antonio Quijarro Province, Bolivia, where crystals up to a millimeter in size have been found.<ref>{{Cite book|title=Minerals encyclopedia|last=Petr Korbel, Milan Novák|publisher=Nebel Verlag GmbH|year=2002|isbn=3-89555-076-0|location=Eggolsheim|pages=44}}</ref> Other localities include:<ref name=":0" />
Weintraube Mine, Lerbach, Rosenhof veins, Clausthal-Zellerfeld, Harz, Lower Saxony, Germany.
Tumiñico Mine, Sierra de Cacho, Villa Castelli, General La Madrid department, La Rioja, Argentina.
Yutangba Selenium deposit, Enshi Co., Enshi Tujia and Miao Autonomous Prefecture (E'xi Autonomous Prefecture), Hubei Province, China.
== See also == * List of minerals * List of minerals named after people
== References == {{Reflist}}
Category:Selenide minerals Category:Copper(II) minerals