Domeykit

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Domeykit
Domeykite-Copper-Quartz-42135.jpg
Massive aggregate of brass-colored domeykite with quartz and copper from the Mohawk Mine in Keweenaw County, Michigan
General and classification
chemical formula α-Cu 3 As
Mineral class
(and possibly department) 		Sulphides, alloys and alloy-like compounds
System no. to Strunz
and to Dana 		2.AA.10 ( 8th edition : II / A.01)
02.02.02.01
Crystallographic Data
Crystal system cubic
Crystal class ; symbol isometric hexagonal 4 3 m
Room group (no.) I 4 3 d (No. 220)
Lattice parameters a  = 9.62  Å
Formula units Z  = 16
Physical Properties
Mohs hardness 3 to 3.5
Density (g / cm 3 ) measured: 7.2 to 7.9; calculated: 7.92
Cleavage no
Break ; Tenacity uneven
colour tin white to steel gray, tints yellow with a brown coating
Line color gray to black
transparency opaque
shine Metallic luster

Domeykite , also known under the mining names arsenic copper and arsenic copper or as a chemical compound copper (I) arsenide , is a rarely occurring mineral from the mineral class of " sulfides and sulfosalts ". It crystallizes in the cubic crystal system with the chemical composition α-Cu 3 As and develops mainly bunchy, massive aggregates in tin-white to steel-gray color and gray to black line color . After some time in the air, Domeykit gets an initially yellowish coating, which becomes light brownish in the further course of weathering and finally shimmers brightly .


Etymology and history

Domeykit was named after Ignacy Domeyko (1802-1889), a Polish geologist and mineralogist.

A first description of the mineral under the name arsenic copper can be found in 1837 in the Annals of Physics and Chemistry by Zinken . In the annual report on the progress of chemistry (Volume 24, 1844) Jöns Jakob Berzelius reports on an arsenic copper found by Domeyko in Coquimbo. However, the mineral was first given the name domeykit, which is valid today, from Wilhelm Ritter von Haidinger , who classified it in the order of "gravel" in his handbook of determining mineralogy published in 1845 .

Another arsenic copper (Cu 6 As with 83.5% copper and 16.5% arsenic) , also found for the first time in the “Los Algodones Mine” near La Serena in the Coquimbo region and originally thought to be silver , was described as algodonite .

classification

In the now outdated, but still in use 8th edition of the mineral classification according to Strunz , the domeykite belonged to the mineral class of "sulfides and sulfosalts" and there to the department of "alloys and alloys". alloy-like compounds ”, where it formed an independent group together with algodonite , cuprostibite , koutekit , kutinaite and novákit .

The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), also assigns the domeykite to the class of “sulfides and sulfosalts (sulfides, selenides, tellurides, arsenides, antimonides, bismuthides, sulfarsenites, sulfantimonites , Sulfbismuthite) ”and there in the section“ Alloys and alloy-like compounds ”. However, this section is further subdivided according to the metals that predominate in the compound, so that the mineral can be found in the subdivision "Compounds of semi-metals with copper (Cu), silver (Ag), gold (Au)", where it is located forms the unnamed group 2.AA.10b as the only member .

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the domeykit to the class of "sulphides and sulphosalts" and there to the category of "sulphide minerals". Here he is together with Kutinait and Dienerit in the "Domeykitgruppe" named after him with the system no. 02.02.02 within the subsection " Sulphides - including selenides and tellurides - with the composition AmBnXp, with (m + n): p = 3: 1 ".

Modifications and varieties

A mineral mixture of domeykite, algodonite and arsenic-rich copper is known as mohawkite .

Education and Locations

Domeykite and algodonite intergrowth from the Cashin Mine in Montrose County , Colorado, USA

Domeykit forms hydrothermally together with algodonite , cuprite ( copper (I) oxide ), copper , silver and nickeline (red nickel pebbles), with which domeykit alternates in thin layers. In addition to the forms described above, it can also be in the form of a kidney, coarse or broken.

In total, Domeykit has so far (as of 2011) been found at around 70 sites. In addition to its type locality "Los Algodones Mine" in the Región de Coquimbo , the mineral was also found near Chañarcillo and San Antonio in the Región de Atacama .

In Germany, Domeykit was found near Dörrmorsbach and on the Hartkoppe near Sailauf in Bavaria, near Kastel in the Saarland community of Nonnweiler and on Helgoland in Schleswig-Holstein. In Austria, domeykit has so far only occurred in the copper deposit near the municipality of Flatschach in Styria and in Switzerland so far only in the municipality of Leysin in the canton of Vaud.

The largest known deposits are on the Keweenaw Peninsula in the US state of Michigan and in Talmessi and Anarak in Iran . Běloves near Náchod in the Czech region of Hradec Králové, where massive mineral aggregates of up to five centimeters in size have been found, is worth mentioning due to the extraordinary domeykite finds.

Other locations are in Argentina , Bolivia , France , Italy , Canada , Namibia , New Zealand , Russia , Sweden , Hungary , the United Kingdom (Great Britain) and the United States of America (USA).

Crystal structure

Structural model of domeykit

Domeykit crystallizes cubically in the space group I 4 3 d (space group no. 220) with the lattice parameter a  = 9.62  Å and 16 formula units per unit cell .

See also

Individual evidence

  1. ↑ a b c d e Hugo Strunz , Ernest H. Nickel: Strunz Mineralogical Tables . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p. 57 .
  2. ↑ Handbook of Mineralogy - Domeykite (English, PDF 62.3 kB)
  3. ↑ Annual Report on the Advances in Chemistry, Volume 24 (available online via Google Book Search)
  4. ↑ Excerpt from the manual of determining mineralogy (PDF 239.5 kB; p. 5)
  5. ↑ Mindat - number of locations
  6. ↑ Petr Korbel, Milan Novák: Mineral Encyclopedia . Nebel Verlag GmbH, Eggolsheim 2002, ISBN 3-89555-076-0 , p. 19 ( Dörfler Natur ).

literature

Web links

Commons : Domeykite  - collection of images, videos and audio files