Isocubanite

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Isocubanite
General and classification
other names
  • Chalkopyrrhotin (after Blomstrand , 1870)
  • Cubanit II (after Ramdohr , 1926)
  • IMA1983-E
  • Isochalcopyrite (English: Isochalcopyrite )
chemical formula CuFe 2 S 3
Mineral class
(and possibly department) 		Sulfides and sulfosalts
System no. to Strunz
and to Dana 		2.CB.55b ( 8th edition : II / C.04)
02.09.13.03
Crystallographic Data
Crystal system cubic
Crystal class ; symbol cubic hexakisoctahedral; 4 / m  3  2 / m
Space group Fm 3 m (No. 225)Template: room group / 225
Lattice parameters a  = 5.30  Å
Formula units Z  = 4/3
Twinning after <111>
Physical Properties
Mohs hardness 3.5 (VHN 100 = 175)
Density (g / cm 3 ) measured: not defined; calculated: 3.93
Cleavage not observed
Break ; Tenacity uneven; brittle
colour bronze colored
Line color not defined
transparency opaque
shine Metallic luster

Isocubanite is a seldom occurring mineral from the mineral class of "sulfides and sulfosalts" with the chemical composition CuFe 2 S 3 and thus, chemically speaking, a copper - iron - sulfide .

Isocubanite crystallizes in the cubic crystal system and arises as a high-temperature modification from cubanite . It is therefore mostly found in the form of fine crustan on the edges of cubanite, consisting of tiny, idiomorphically developed cuboctahedral crystals up to about 400  μm in size, but also occurs together with chalcopyrite . The surfaces of the bronze-colored, opaque crystals have a metallic sheen .

Etymology and history

As a synthetic product, isocubanite was prepared as early as 1970 by heating cubanite and analyzed crystallographically.

In nature, isocubanite was first discovered in mineral samples by a black smoker on the so-called "TAG Hill" (EPR 21 ° N) on the East Pacific Ridge . It was first described in 1988 by René Caye, Bernard Cervelle, Fabien Cesbron, Elisabeth Oudin, Paul Picot and François Pillard, who named the mineral based on its cubic (isometric) symmetry and relationship with cubanite .

A mineral from the southwestern basin of the Red Sea ( Atlantis II depth ) described in 1989 by E. Missack, P. Stoffers, A. El Goresy under the name isochalkopyrite (English: Isochalcopyrite ) was discredited in 2006 as being identical to isocubanite.

The term Chalkopyrrhotin (English Chalcopyrrhotite ) was first coined by Christian Wilhelm Blomstrand in 1870 for a material from Nya Kopparberg in Sweden that was similar in color to pyrite . In 1924 Per Geijer (1886–1976) identified the material as cubanite and the name Chalkopyrrhotin was discredited accordingly. A subsequent investigation by the Mineralogical Department of the British Museum of Natural History using topographic material confirmed that it was a mixture without isotropic material. According to Paul Ramdohr , chalcopyrrhotite is identical to the mineral that various researchers call cubic cubanite , which Ramdohr himself called cubanite II .

The type material (cotype) of the mineral is kept in the Mines ParisTech (also École nationale supérieure des mines de Paris , ENSM) in Paris .

classification

Already in the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the isocubanite belonged to the mineral class of "sulfides and sulfosalts" and there to the department of "sulfides with the molar ratio of metal: S, Se, Te ≈ 1: 1", where together with Haycockit , Mooihoekit , Orickit , Putoranit , Talnakhit and Wilhelmramsayit he formed the unnamed group II / C.04 .

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 classifies isocubanite in the category of "Metal sulfides, M: S = 1: 1 (and similar)". However, this is further subdivided according to the predominant metals in the compound, so that the mineral can be found in the sub-section "with zinc (Zn), iron (Fe), copper (Cu), silver (Ag) etc." according to its composition where it is the only member of the unnamed group 2.CB.55b .

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns isocubanite to the class of "sulphides and sulphosalts" and there in the category of "sulphide minerals". Here it is together with cubanite and argentopyrite in the " cubanite group " with the system no. 02.09.13 within the subsection "Sulphides - including selenides and tellurides - with the composition A m B n X p , with (m + n): p = 1: 1".

Crystal structure

Isocubanite crystallizes cubically in the space group Fm 3 m (space group no. 225) with the lattice parameter a = 5.30  Å and 4/3 formula units per unit cell . Template: room group / 225

Modifications and varieties

Like diamond, isocubanite belongs to the metastable modifications , i.e. it is only stable above 210 ° C and below this temperature would have to convert back into the orthorhombic modification cubanite. So far, however, laboratory tests have not succeeded in converting isocubanite back into cubanite.

In addition to the high-temperature modification isocubanite, a high-pressure modification with hexagonal symmetry could also be represented. This arises from orthorhombic cubanite at room temperature under a pressure of about 3.3  GPa .

Education and Locations

Isocubanite forms when cubanite is heated to 200 to 270 ° C. But could also be obtained by heating mixtures of mineral chalcopyrite and pyrrhotite are synthesized at a temperature of about 240 ° C, with which Isocubanit next and Cubanit and pyrrhotite anhydrite , pyrite , sphalerite and wurtzite in nature associated occurs.

Isocubanite is found mainly on submarine black smokers , but also in hydrothermal copper sulphide deposits and in volcanic pumice deposits .

So far only a few sites for isocubanite are known. In addition to its type locality , the black smoker "EPR 21 ° N", the mineral on the East Pacific Ridge was also found in some mineral samples from the Explorer Ridge , the Central and Escanaba Valley and from the Bent Hills area on the Juan-de-Fuca Back to be discovered. Isocubanite is also known from mineral samples from the Atlantis II depth in the Red Sea and from some mineral samples from the Mid-Atlantic Ridge, such as from the hydrothermal fields Ashadze , Logatchev-1 , Rainbow , Snake Pit and Turtle Pits .

In Germany, isocubanite has so far been found in the Deyerling quarry near Holenbrunn , a marble quarry near Sinatengrün and in the Bayerland mine near Pfaffenreuth (municipality of Leonberg ) in Bavaria and at Ettringer Bellerberg in Rhineland-Palatinate.

Other sites were found in the Italian municipality of Berceto , on Mount Dzhaltul near Kureika in the Krasnoyarsk region and the copper-zinc deposit Yaman-Kasy in the Mednogorsk district (Urals) in Russia, in the Boranja ore field in Serbia and on the Kīlauea volcano in Hawaii known.

In addition, the mineral could still be detected in numerous meteorites . The only unequivocally documented location for isocubanite in Austria is a meteorite called Lanzenkirchen , which fell in 1925 near the municipality of the same name in Lower Austria .

Other meteorite finds include Kandahar in the province of the same name in Afghanistan, Ehole in the Angolan province of Cunene ; Adelie Land in Antarctica, Malotas in the Argentine Salavina Department , Dokachi in the Dhaka district of Bangladesh, Tourinnes-la-Grosse near the Belgian municipality of Beauvechain , Zavid near Zvornik in Bosnia and Herzegovina, Nadiabondi in Burkina Faso , Cobija in Chile , Heredia in Costa Rica , Aarhus and Mern in Denmark , Valkeala and Bjurböle in Finland , Djati-Pengilon and Bandong in Indonesia , Yonozu (meteorite) Yonozu on the Japanese island of Honshū , Phum Sambo in Cambodia , Lixna and Buschhof in Latvia , N'Goureyma in Mali , the Udei station group (see IAB meteorites ) on Benue in Nigeria, Tysnes Island in the island commune of the same name in Norway, Pultusk in Poland, Monze in Zambia, Jelica in Serbia , Mangwendi in Zimbabwe, Bur-Gheluai in Somalia , Sena and Olivenza in the communities of the same name in Spain , Maridi in South Sudan , Přibram in the Czech Republic, Soroti in Uganda and Wold Cottage in Yorkshire and Appley Bridge in Lan cashire in the England part of the United Kingdom. In addition, there are many meteorite finds in different regions of Algeria, Australia, Brazil, Germany, France, India, Italy, Canada, Romania, Russia, Sweden, South Africa, the Ukraine and the United States of America.

See also

literature

  • ME Fleet: Refinement of the crystal structure of cubanite and polymorphism . In: Journal of Crystallography . tape 132 , 1970, pp. 276–287 (English, rruff.info [PDF; 591 kB ; accessed on October 24, 2018]).
  • JT Szymański: The crystal structure of high-temperature CuFe2S3 . In: Journal of Crystallography . tape 140 , 1970, pp. 240–248 (English, rruff.info [PDF; 435 kB ; accessed on October 24, 2018]).
  • John Leslie Jambor , Jacek Puziewicz: New mineral names . In: American Mineralogist . tape 74 , 1989, pp. 500–505 (English, minsocam.org [PDF; 570 kB ; accessed on October 21, 2018]).

Web links

Individual evidence

  1. ↑ a b c d René Caye, Bernard Cervelle, Fabien Cesbron, Elisabeth Oudin, Paul Picot, François Pillard: Isocubanite, a new definition of the cubic polymorph of cubanite CuFe 2 S 3 . In: Mineralogical Magazine . tape 52 , 1988, pp. 509-514 (English, rruff.info [PDF; 425 kB ; accessed on October 21, 2018]).
  2. ↑ Mineral Atlas : Isochalkopyrite
  3. ↑ a b Ernst AJ Burke: A mass descreditation of GQN minerals . In: The Canadian Mineralogist . tape 44 , 2006, pp. 1557–156 (English, rruff.info [PDF; 116 kB ; accessed on October 24, 2018]).
  4. ↑ a b c JT Szymański: The crystal structure of high-temperature CuFe 2 S 3 . In: Journal of Crystallography . tape 140 , 1970, pp. 240–248 (English, rruff.info [PDF; 435 kB ; accessed on October 24, 2018]).
  5. ^ A b 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.  77 (English).
  6. ↑ 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 .
  7. ↑ a b c Isocubanites . 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; 62  kB ; accessed on October 21, 2018]).
  8. ↑ a b Mindat - Isocubanite (English)
  9. ^ ME Fleet: Refinement of the crystal structure of cubanite and polymorphism . In: Journal of Crystallography . tape 132 , 1970, pp. 276–287 (English, rruff.info [PDF; 591 kB ; accessed on October 24, 2018]).
  10. ^ John Leslie Jambor , Jacek Puziewicz: New Mineral Names . In: American Mineralogist . tape  75 , 1990, pp. 431–438 (English, minsocam.org [PDF; 964 kB ; accessed on October 24, 2018]).
  11. ^ Edward Salisbury Dana: The system of mineralogy of James Dwight Dana. 1837-1868 . 6th edition. John Wiley & Sons, New York 1904, p. 79 (English, available online at archive.org  - Internet Archive ).
  12. ^ A b Paul Ramdohr : The ore minerals and their adhesions . 4th, revised and expanded edition. Akademie-Verlag, Berlin 1975, p.  583-584, 685 .
  13. ↑ Catalog of Type Mineral Specimens - I. (PDF 29 kB) In: docs.wixstatic.com. Commission on Museums (IMA), December 12, 2018, accessed August 29, 2019 .
  14. ↑ a b Entry on Cubanite. In: Römpp Online . Georg Thieme Verlag, accessed on October 21, 2018.
  15. ↑ a b List of sites for isocubanite in the Mineralienatlas and Mindat
  16. ↑ Meteoritical Bulletin Database - Lanzenkirchen