Kruťait

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Kruťait
Krutaite-91146.jpg
from the El Dragón Mine, Antonio Quijarro Province (Potosí), Bolivia (image width 2.5 mm)
General and classification
other names
  • Krut'ait, Krut'ait or Krutait
  • IMA 1972-001
chemical formula CuSe 2
Mineral class
(and possibly department) 		Sulfides and sulfosalts
System no. to Strunz
and to Dana 		2.EB.05a
02.12.01.08
Crystallographic Data
Crystal system cubic
Crystal class ; symbol cubic-disdodecahedral; 2 / m  3
Space group Pa 3 (No. 205)Template: room group / 205
Lattice parameters a  = 6.06  Å
Formula units Z  = 4
Physical Properties
Mohs hardness 4 (VHN 25 = 248)
Density (g / cm 3 ) calculated: 6.53
Cleavage Well
Break ; Tenacity not defined
colour Gray
Line color dark gray
transparency opaque (opaque)
shine Metallic luster

Kruťait , mostly simplified Krut'ait or Krut'ait or Krutait written, is a very rarely occurring mineral from the mineral class of "sulfides and sulfosalts" (including selenides, tellurides, arsenides, antimonides and bismuthides). It crystallizes in the cubic crystal system with the chemical composition CuSe 2 , so it is chemically seen a copper - selenide , more Kupferdiselenid .

So far, Kruťaite could only be found in the form of massive mineral aggregates consisting of microscopic crystals up to a maximum of one millimeter in size. The mineral is opaque in every form and has a gray, metallic sheen color with a dark gray streak color .

Etymology and history

The mineral was first discovered near Petrovice ( Peterswald ) in Okres Žďár nad Sázavou ( Saar district ) in the Czech Republic and described in 1972 by Zdenek Johan, Paul Picot, Roland Pierrot and Milan Kvaček, who named it after the Czech mineralogist and director of the mineralogical laboratory in Moravia Brno Provincial Museum named Tomáš Kruťa (1906–1998).

Since the namesake Kruťa is spelled with a palatalized t ( pronunciation similar to the Low German tj as in Matjes), the mineral name Kruťait is typographically correct in accordance with the provisions of the International Mineralogical Association (IMA). Due to technical limitations in the illustration, this special character is mostly replaced by an apostrophe after the t in more recent publications ( Krut'ait , Krut'ait ) or was omitted entirely in older publications ( Krutait ).

classification

The Kruťait is not yet recorded in the outdated 8th edition of the Strunz mineral classification . Only in the Lapis mineral directory according to Stefan Weiß, which, out of consideration for private collectors and institutional collections, is still based on this old form of Karl Hugo Strunz's system , was the mineral given the system and mineral number. II / D.17-70 . In the "Lapis system" this corresponds to the class of "sulfides and sulfosalts" and there the section "Sulfides with metal: S, Se, Te <1: 1", where Kruťait (here, simplified Krutait or Krut'ait ) together with Aurostibit , cattierite , Changchengit , Dzharkenit , Erlichmanit , Fukuchilit , Geversit , Hauerit , Insizwait , Laurit , Maslovit , Mayingit , Michenerit , Padmait , Penroseite , pyrite , Sperrylith , Testibiopalladit , Trogtalit , Vaesit and Villamanínit the "pyrite group" with the system No. II / D.17 forms (as of 2018).

The 9th edition of Strunz's mineral systematics, valid since 2001 and updated by the International Mineralogical Association (IMA) until 2009, assigns the Kruťaite to the class of "sulfides and sulfosalts", but in the department of "metal sulfides with M: S ≤ 1: 2 “. This is further subdivided according to the exact molar ratio and the predominant metals in the compound so that the mineral can be found in the sub-section "M: S = 1: 2, with Fe, Co, Ni, PGE etc." where it together with Aurostibit, cattierite, Dzharkenit, Erlichmanit, Fukuchilit, Gaotaiit , Geversit, Hauerit, Insizwait, Iridisit , Laurit, Penroseite, pyrite, Sperrylith, Trogtalit, Vaesit and Villamanínit also "pyrite group" with the system no. 2.EB.05a forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns hauerite to the class of "sulphides and sulphosalts" and there in the category of "sulphide minerals". Here, too, it is in the "pyrite group (isometric: Pa 3 )" with the system no. 02.12.01 to be found within the subsection “ Sulphides - including selenides and tellurides - with the composition A m B n X p , with (m + n): p = 1: 2 ”. Template: room group / 205

Crystal structure

Kruťait crystallizes cubically in the space group Pa 3 (space group no. 205) with the lattice parameter a  = 6.06  Å and four formula units per unit cell . Template: room group / 205

Education and Locations

Kruťaite is formed by hydrothermal processes. Berzelianite , Bukovite , Chalcopyrite , Clausthalite , Eskebornite , Ferroselite , Goethite , Hematite , Umangite and / or Uraninite can occur as accompanying minerals , depending on where they were found .

As a very rare mineral formation, only a few samples of the Kruťaite from less than 10 sites have been found (as of 2014). Its type locality Petrovice ( Peterswald ) is also the only known site in the Czech Republic to date.

The “El Dragón Mine” in the province of Antonio Quijarro (Potosí) in Bolivia, where crystals up to one millimeter in size have been found, is known for its extraordinary Kruťaite finds.

The only place of discovery in Germany so far is the "Weintraube" pit near Lerbach (Osterode am Harz) in Lower Saxony. In addition, the mineral is known so far only from the "Tumiñico Mine" in the Sierra de Cacho and from Los Llantenes in the Vinchina department in the La Rioja province as well as from the Sierra de Cacheuta in the Mendoza province of Mendoza in Argentina and from the Yutangba selenium - Deposit at Enshi in China.

See also

literature

  • Zdenek Johan, Paul Picot, Roland Pierrot, Milan Kvaček: La krutaïte, CuSe 2 , un nouveau minéral du groupe de la pyrite . In: Bulletin de la Société Française de Minéralogie et de Cristallographie . tape 95 , 1972, pp. 475–481 (French, rruff.info [PDF; 400 kB ; accessed on March 28, 2020]).
  • Friedrich Klockmann : Klockmann's textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp. 459 (as  krutaite ) (first edition: 1891).

Web links

Commons : Krut'aite  - collection of images, videos and audio files

Individual evidence

  1. ↑ a b c d e f Hugo Strunz , Ernest H. Nickel : Strunz Mineralogical Tables. Chemical-structural Mineral Classification System . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p.  103 (as  Krutaite ) (English).
  2. ↑ a b c Stefan Weiss: The large Lapis mineral directory. All minerals from A - Z and their properties. Status 03/2018 . 7th, completely revised and supplemented edition. Weise, Munich 2018, ISBN 978-3-921656-83-9 .
  3. ↑ a b Kruťaite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 (English, handbookofmineralogy.org [PDF; 63  kB ; accessed on March 28, 2020]).
  4. ^ Ernst AJ Burke: Tidying up Mineral Names: an IMA-CNMNC Scheme for Suffixes, Hyphens and Diacritical marks . In: Mineralogical Record . tape 39 , no. 2 , March 2008 (English, cnmnc.main.jp [PDF; 2.4 MB ; accessed on March 28, 2020]).
  5. ↑ Malcolm Back, William D. Birch, Michel Blondieau and others: The New IMA List of Minerals - A Work in Progress - Updated: March 2020. (PDF; 2.44 MB) In: cnmnc.main.jp. IMA / CNMNC, Marco Pasero, March 2020, accessed March 28, 2020 (English, as Krut'ait).
  6. ↑ Hans Jürgen Rösler : Textbook of Mineralogy . 4th revised and expanded edition. German publishing house for basic industry (VEB), Leipzig 1987, ISBN 3-342-00288-3 , p.  299 .
  7. ^ Helmut Schrätze , Karl-Ludwig Weiner : Mineralogie. A textbook on a systematic basis . de Gruyter, Berlin; New York 1981, ISBN 3-11-006823-0 , pp.  244 .
  8. ↑ Kruta, Tomáš, 1906-1998. In: biblio.hiu.cas.cz. Bibliography dějin Českých zemí, accessed on March 28, 2020 (German: Bibliography on the history of the Bohemian countries).
  9. ↑ Ernest H. Nickel , Joel D. Grice: The IMA COMMISSION ON NEW MINERALS AND MINERAL NAMES: Procedures and Guidelines on Mineral Nomenclature, 1998 . In: The Canadian Mineralogist . tape  36 , 1998, pp. 9 ( cnmnc.main.jp [PDF; 328 kB ]).
  10. ↑ Ernest H. Nickel, Monte C. Nichols: IMA / CNMNC List of Minerals 2009. (PDF; 1.82 MB) In: cnmnc.main.jp. IMA / CNMNC, January 2009, accessed March 28, 2020 .
  11. ↑ a b List of locations for Kruťaite in the Mineralienatlas and Mindat , accessed on March 28, 2020.
  12. ↑ Petr Korbel, Milan Novák: Mineral Encyclopedia (=  Dörfler Natur ). Edition Dörfler im Nebel-Verlag, Eggolsheim 2002, ISBN 978-3-89555-076-8 , p. 44 .