Bornite

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Bornite
Bornite-105006.jpg
Greenish tarnished bornite crystals from the "Dzhezkazgan Mine" (Zhezkazgan Mine) near Schesqasghan in Kazakhstan (field of view 7 mm)
General and classification
other names
  • Deep bornite
  • Colored copper gravel
chemical formula Cu 5 FeS 4
Mineral class
(and possibly department) 		Sulfides and sulfosalts
System no. to Strunz
and to Dana 		2.BA.10 ( 8th edition : II / B.02)
05/02/02/01
Crystallographic Data
Crystal system orthorhombic
Crystal class ; symbol orthorhombic-dipyramidal; 2 / m  2 / m  2 / m
Space group see crystal structure
Lattice parameters see crystal structure
Formula units see crystal structure
Twinning after {111}, often penetrating twins
Physical Properties
Mohs hardness 3 to 3.25
Density (g / cm 3 ) measured: 5.06 to 5.08; calculated: 5.074
Cleavage indistinct after {111}
Break ; Tenacity uneven to scalloped
colour bronze - to copper-colored , tinged with different colors
Line color grey black
transparency opaque
shine Metallic sheen, iridescent violet
magnetism magnetic after heating

Bornite ( deep bornite ), also called colored copper gravel , copper lazur or copper lazur , is a frequently occurring mineral from the mineral class of " sulfides and sulfosalts ". It crystallizes in the orthorhombic crystal system with the chemical composition Cu 5 FeS 4 and develops mostly massive aggregates, more rarely crystals in octahedron - or pseudocubic form in bronze or copper color.

Etymology and history

Bornite with pseudokubischem habit of quartz from the "Huaron Mining District" at de Cerro Pasco , Peru

Bornite had been known since 1725, but it was not officially named until 1845 from Wilhelm Ritter von Haidinger , who named the mineral after the Austrian mineralogist Ignaz von Born . The mineral was given its mining name colored copper gravel because it quickly forms brightly colored tarnish in air .

The type locality is Jáchymov (German Sankt Joachimsthal ) in the Czech Republic.

classification

In the now outdated, but still in use 8th edition of the mineral classification according to Strunz , bornite belonged to the mineral class of "sulfides and sulfosalts" and there to the department of "sulfides with the molar ratio of metal: sulfur, selenium, tellurium> 1: 1", where together with betechtinite , gortdrumite and calvertite the group of the “complex copper-iron-sulfides” with the system no. II / B.02 .

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 bornite in the category of "Metal sulfides, M: S> 1: 1 (mainly 2: 1)". This is, however, further subdivided according to the predominant metals in the compound, so that the mineral can be found according to its composition in the sub-section "with copper (Cu), silver (Ag), gold (Au)", where it is the only member unnamed group forms 2.BA.10 .

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns bornite to the class of "sulfides and sulfosalts" and there in the department of "sulfide minerals". Here he is to be found as the only member in the unnamed group 02.05.02 within the subdivision of " Sulphides - including selenides and tellurides - with the composition AmBnXp, with (m + n): p = 3: 2 ".

Crystal structure

Bornite initially crystallizes as high bornite (β-Cu 5 FeS 4 ) in the cubic crystal system in the space group Fm 3 m (space group no. 225) with the lattice parameter a  = 5.50  Å and one formula unit per unit cell . After further cooling, it changes at around 270 to 265 ° C into intermediate bornite with a metastable , cubic structure, and finally at around 205 to 195 ° C into the stable, orthorhombic deep bornite , whose unit cell has the lattice parameter a  = 10.95 Å; b  = 21.86 Å and c  = 10.95 Å and whose 16 formula units are arranged in the space group Pbca (No. 61) . Template: room group / 225 Template: room group / 61

properties

Bluish-violet bornite with a strong metallic sheen from Tsumeb , Namibia

Bornite melts in front of the soldering tube to form a gray and magnetic ball. In nitric acid and concentrated hydrochloric acid , the mineral is dissolved, said sulfur is deposited.

In the fresh state, bornite can be confused with pyrrhotite and nickeline , bluish green or colored tarnished with chalcopyrite or covelline .

Education and Locations

Solid silver on bornite and calcite from the " San Martín Mine", Municipio de Sombrerete, Zacatecas , Mexico

As a so-called “run-through mineral”, bornite can arise under various educational conditions and with numerous parageneses .

It can be found as an accessory component in igneous rocks and intramagmatic sulphide deposits as well as in carbonatites near Phalaborwa and Okiep and in Namaqualand in South Africa. Bornite is also widespread as a secondary component in low-iron copper deposits, created by pneumatolytic and hydrothermal processes within pegmatites or skarns , such as in Tsumeb and Musina (formerly Messina ) in South West Africa and near Butte in the US state of Montana .

However, bornite forms most frequently in sedimentary sulphide deposits such as in the copper slates of Thuringia and Hesse and in the Mansfeld copper slate in Saxony-Anhalt . Bornite, on the other hand, forms rather rarely in the cementation zones of copper deposits.

In addition, bornite can be produced secondary from chalcopyrite under the action of hot solutions together with magnetite , hematite and often also chalcosine , such as in Siegerland in North Rhine-Westphalia, Berggießhübel in Saxony, near Kupferberg in Silesia, in the Swedish municipality of Norberg and near Redruth in the British county of Cornwall .

Bornite weathers relatively easily via the intermediate stages chalcosine, covelline and idaite to azurite and malachite . Accordingly, it enters paragenesis with the minerals mentioned above, but also with other copper and iron minerals such as. B. pyrite as well as calcite , various garnets , pyrite, quartz and wollastonite .

Bornite is a frequent mineral formation that can be found at many sites, with more than 5,000 sites known to date (as of 2017). In addition to its type locality Jáchymov ( Sankt Joachimsthal ), the mineral occurred in the Czech Republic in many other places in Bohemia and Moravia , including Příbram , the Hradec Králové and Karlovy Vary ( Karlsbad ) region, Silesia and Vysočina .

Among other things, Bisbee in the US state of Arizona, where masses weighing tons and crystals with a diameter of up to 2 cm (“Cole Mine”) were unearthed, is worth mentioning due to the extraordinary bornite finds . Beautifully developed crystals up to 4 cm in size were found in the " Dzhezkazgan Mine" in the area of ​​Karagandy in Kazakhstan . From Likasi in the Congolese province of Haut-Katanga crystal finds of about 3 cm in size are known and from Carn Brea in Cornwall (England) mostly about 1 cm large crystals come.

Other localities lie in Afghanistan , Egypt , Angola , the Antarctic , in Argentina , Armenia , Australia , Azerbaijan , Belgium , Bolivia , Botswana , Brazil , Bulgaria , Chile , China , Costa Rica , Germany , the Dominican Republic , Ecuador , Eritrea , on Fiji , in Finland , France , Ghana , Greece , Greenland , Haiti , Honduras , India , Indonesia , Iran , Ireland , Italy , Jamaica , Japan , Canada , on the Channel Island Jersey , in Kyrgyzstan , the Democratic Republic of the Congo , Colombia , North and South Korea , Kosovo , Cuba , Madagascar , Malaysia , Mali , Morocco , North Macedonia , Mexico , Mongolia , Myanmar , Namibia , New Zealand , Norway , Oman , Austria , Pakistan , Panama , Papua New Guinea , Peru , the Philippines , in Poland , Portugal , Puerto Rico , Romania , Russia , the Solomon Islands , Zambia , Saudi Arabia , Sweden , Switzerland , Serbia , Sierra Leone , Zimbabwe , Slovakia , Slovenia , Spain , South Africa , Swaziland , Taiwan , Thailand , Turkey , Hungary , Venezuela , the United Kingdom (Great Britain), the United States of America (USA) and Cyprus .

Bornite could also be detected in several rock samples from the Mid-Atlantic Ridge , the Central Indian Ridge and the East Pacific Ridge as well as outside the Earth on the moon .

use

Bornite is an important copper ore due to its high copper content of around 63 percent by weight and its widespread occurrence .

See also

literature

Web links

Commons : Bornit (e)  - Collection of images, videos and audio files

Individual evidence

  1. ↑ a b c d 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.  63 .
  2. ↑ Webmineral - Bornite (English)
  3. ↑ a b c d e Bornite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 ( handbookofmineralogy.org [PDF; 63  kB ; accessed on May 14, 2017]).
  4. ↑ Mindat - description of the location and mineral list of Jáchymov (St Joachimsthal)
  5. ↑ Entry on bornite. In: Römpp Online . Georg Thieme Verlag, accessed on July 13, 2011.
  6. ↑ a b c d e Friedrich Klockmann : Klockmann's textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp.  419-420 (first edition: 1891).
  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.  127-128 .
  8. ↑ Mindat - Number of localities for bornite
  9. ↑ Petr Korbel, Milan Novák: Mineral Encyclopedia (=  Dörfler Natur ). Nebel Verlag, Eggolsheim 2002, ISBN 978-3-89555-076-8 , p. 22 .
  10. ↑ Find location list for bornite in the Mineralienatlas and Mindat