Carrollite

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Carrollite
Carrollite, Dolomite, Siderite, Malachite-792195.jpg
Silvery shiny carrollite octahedron with white dolomite , yellow siderite and green malachite from the Kamoya South II mine , Democratic Republic of the Congo
General and classification
chemical formula
  • CuCo 2 S 4
  • Cu (Co, Ni) 2 S 4
Mineral class
(and possibly department)
Sulfides and sulfosalts
System no. to Strunz
and to Dana
2.DA.05 ( 8th edition : II / D.01)
02.10.01.02
Crystallographic Data
Crystal system cubic
Crystal class ; symbol cubic hexakisoctahedral; 4 / m  3  2 / m
Space group Fd 3 m (No. 227)Template: room group / 227
Lattice parameters a  = 9.48  Å
Formula units Z  = 8
Twinning according to {111} polysynthetic and lamellar
Physical Properties
Mohs hardness 4.5 to 5.5 ( VHN 100 = 507 to 586)
Density (g / cm 3 ) measured: 4.5 to 4.8; calculated: 4.83
Cleavage imperfect after {001}
Break ; Tenacity uneven to slightly scalloped; very brittle
colour light gray, silver gray to steel gray, tapering copper red to gray purple
Line color grey black
transparency opaque
shine Metallic luster

Carrollite is a rather seldom occurring mineral from the mineral class of "sulphides and sulphosalts" with the idealized chemical composition CuCo 2 S 4 and therefore, chemically speaking, a copper - cobalt - sulphide and the sulfur analogue of tyrrellite . However, since part of the cobalt in natural carrollites is often replaced ( substituted ) by nickel , the formula is also given in various sources as Cu (Co, Ni) 2 S 4 . Structurally, like its selenium analogue tyrrellite, carrollite belongs to the group of spinels .

Carrollite crystallizes in the cubic crystal system and often develops octahedral or cube-shaped crystals and cubic combinations such as cuboctahedra , but also occurs in the form of granular to massive mineral aggregates . The non-transparent (opaque) crystals are light gray to steel gray in color and show a metallic sheen on the surfaces . Over time, the surfaces can turn copper-red to gray-violet, occasionally also brightly colored.

Etymology and history

Carrollite was first discovered in mineral samples from the Patapsco iron and copper mine near Finksburg in Carroll County of the US state of Maryland . The first description was in 1852 by the metallurgist and mining engineer WL Faber, who named the mineral after the county in which its type locality is located.

A storage location for the type material of the mineral is not known.

Carrollit was already known before the International Mineralogical Association (IMA) was founded in 1958 and was mostly recognized as a mineral in the professional world, even if, according to Hans Jürgen Rösler, among other things, it was regarded as a variety of Linneit with 10 to 19% copper instead of cobalt. As a so-called grandfathered mineral (G), Carrollite was recognized as an independent mineral type by the Commission on new Minerals, Nomenclature and Classification (CNMNC).

classification

The structural classification of IMA is one of the Carrollit since 2018 to spinel supergroup , where he together with Cuproiridsit , Cuprokalininit , Fletcherit , Florensovit , Malanit , Rhodostannit and Toyohait forms the Carrollit subgroup within the thiospinels.

The well-known mineral systematics, which are initially classified according to chemical composition, classify Carrollite in the mineral class of "sulfides and sulfosalts".

In the outdated 8th edition of the mineral classification by Strunz of Carrollit belonged there to the department of "sulfides with M: S <1: 1", where he together with Bornhardtit, daubréelite , greigite , Indit , linneite , Polydymit , Siegenit , Trüstedtit , Tyrrellit and Violarit the "Linneit series" with the system no. II / C.01 formed.

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 , the mineral was given the system and mineral number. II / D.01-40 . In the "Lapis system" this also corresponds to the section "Sulphides with [the molar ratio] metal: S, Se, Te <1: 1", where Carrollite together with Bornhardtite, Cadmoindite , Cuprokalininite , Daubréelite , Fletcherite , Florensovite , Greigite, Indit, Kalininit , Linneit, Polydymit, Siegenit, Trüstedtit, Tyrrellite and Violarit form the "Linneit Group" (as of 2018).

The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and was updated by the IMA until 2009, classifies carrollite in the initially more general section of "Metal sulfides with M: S = 3: 4 and 2: 3". This is further subdivided according to the exact molar ratio, so that the mineral can be found according to its composition in the sub-section "M: S = 3: 4", where it is found together with Bornhardtite, Cadmoindite, Cuproiridsite , Cuprorhodsite , Daubréelite, Ferrorhodsite , Fletcherite, Florensovit, greigite, Indit, Kalininit, linneite, Malanit , Polydymit, Siegenit, Trüstedtit, Tyrrellit, Violarite and Xingzhongit the "Linneitgruppe" system no. 2.DA.05 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the carrollite to the “sulphide minerals” division and there also to the “Linneit group (isometric: Fd 3 m )” with the system no. 02.10.01 within the subsection " Sulphides - including selenides and tellurides - with the composition A m B n X p , with (m + n): p = 3: 4 ". Template: room group / 227

Chemism

The idealized, theoretical compound CuCo 2 S 4 consists of 20.52% copper (Cu), 38.06% cobalt (Co) and 41.41% sulfur (S). In the case of natural samples, however, the weight percentages differ to a greater or lesser extent due to the formation of mixed crystals or foreign admixtures . For example, small amounts of iron (Fe) between 0.6 and 2.25% were measured in the samples analyzed from the Democratic Republic of the Congo (formerly Zaire), Gladhammar in Sweden and Siegen in Germany .

Crystal structure

Carrollite crystallizes cubically in the space group Fd 3 m (space group no. 227) with the lattice parameter a  = 9.48  Å and 8 formula units per unit cell . Template: room group / 227

Education and Locations

Almost perfect carrollite cuboctahedron from the Kamoya South II mine , Democratic Republic of the Congo (size 2.3 cm × 1.4 cm × 1.2 cm)
Carrollite (shiny silvery octahedron) and chalcopyrite (gold colored) on calcite from the Kamoya South II mine , Democratic Republic of the Congo (size 52 mm × 46 mm × 41 mm)
Colorful tarnished carrollite (largest crystal 7 mm) from the Kamoto Principal Mine, Democratic Republic of the Congo

Carrollit formed in the through hydrothermal formed influences veins , where it with many sulfide minerals associated occurs such as, inter alia, bornite , chalcocite , chalcopyrite , digenite , djurleite , Gersdorffit , Kobaltocalcit , linnaeite , millerite , Polydymit , pyrite , pyrrhotite , sphalerite , Siegenit , tetrahedrite and ullmannite .

As a rather rare mineral formation, Carrollite can sometimes be abundant at different sites, but overall it is not very common. So far, around 160 locations have been documented for Carrollit (as of 2018). In addition to its type locality in the Patapsco mine, the mineral could also be found in Carroll County in the Mineral Hill iron and copper mines near Louisville and Florence and Springfield near Sykesville . Another location in the state of Maryland is the Bare Hills copper mine near the place of the same name in Baltimore County . Furthermore, we know some sites in different US states such as Alaska, Colorado, Missouri, Montana and Wyoming.

In Germany, Carrollit has so far mainly appeared in the mining area around the Siegen district of Eiserfeld , for example in the Eisenzecher Zug and Eiserner Union composite mines as well as the Brüderbund , Eisenhardt and Storch & Schöneberg mines . The mineral was also found in North Rhine-Westphalia in the Glanzenberg mine near Silberg in the Olpe district . Other well-known sites are various mines in the Altenkirchen (Westerwald) district in Rhineland-Palatinate, such as the Bindweide and Wingertshardt mines and an unnamed copper mine near Düppenweiler in the Merzig-Wadern district in Saarland .

In Austria, the mineral has so far only been discovered in the Neufinkenstein-Grabanz mining area on the Mallestiger Mittagskogel in Carinthia and on the Kaiblinggraben in the Kleinveitsch Valley ( Veitschtal ) in Styria.

The only known site in Switzerland so far is the mine de Baicolliou near Grimentz in the canton of Valais.

The province of Katanga in the Democratic Republic of the Congo is known for its extraordinary carrollite finds, and in particular the ore deposits around Kamoya in the district of Kambove and Kolwezi in the province of Lualaba, where well-developed, high-gloss carrollite octahedra and cuboctahedra of up to 2 cm in size emerged.

Other locations are in Australia, China, Canada, Norway, Poland, Russia, Zambia, Sweden and other states of the USA.

use

Carrollite is used as an important cobalt ore in local accumulations, such as in the deposits of the Democratic Republic of the Congo .

See also

literature

  • WL Faber: On carrollite, a new cobalt mineral . In: American Journal of Science and Arts . tape 13 , 1852, p. 418–419 (English, rruff.info [PDF; 204 kB ; accessed on March 30, 2020]).
  • WF Foshag: New Mineral Names . In: American Mineralogist . tape 13 , 1928, pp. 32–34 (English, rruff.info [PDF; 183 kB ; accessed on March 30, 2020]).
  • Thomas Wagner, Nigel J. Cook: Carrollite and related minerals of the linnaeite group: Solid solutions and nomenclature in the light of new data from the Siegerland District, Germany . In: The Canadian Mineralogist . tape 37 , 1999, pp. 545–558 (English, rruff.info [PDF; 1.5 MB ; accessed on March 30, 2020]).

Web links

Commons : Carrollite  - collection of pictures, videos and audio files

Individual evidence

  1. a b c 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 30, 2020 .
  2. 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.  93 .
  3. ^ David Barthelmy: Carrollite Mineral Data. In: webmineral.com. Accessed March 30, 2020 (English).
  4. a b c d e f g Carrollite . 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; 117  kB ; accessed on March 30, 2020]).
  5. ^ Carrollite. In: mindat.org. Hudson Institute of Mineralogy, accessed March 30, 2020 .
  6. a b 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. Example of a carrollite crystal that has tarnished in bright colors. In: mindat.org. Hudson Institute of Mineralogy, accessed March 30, 2020 .
  8. Catalog of Type Mineral Specimens - C. (PDF 131 kB) In: docs.wixstatic.com. Commission on Museums (IMA), December 12, 2018, accessed March 30, 2020 .
  9. 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.  320 .
  10. Ferdinando Bosi, Cristian Biagioni, Marco Pasero: Nomenclature and classification of the spinel supergroup . In: European Journal of Mineralogy . tape 31 , no. 1 , September 12, 2018, p. 183–192 , doi : 10.1127 / ejm / 2019 / 0031-2788 (English).
  11. 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 30, 2020 .
  12. Localities for Carrollite. In: mindat.org. Hudson Institute of Mineralogy, accessed March 30, 2020 .
  13. a b Petr Korbel, Milan Novák: Mineral Encyclopedia (=  Dörfler Natur ). Edition Dörfler im Nebel-Verlag, Eggolsheim 2002, ISBN 978-3-89555-076-8 , p. 38 .
  14. Find location list for Carrollit in the Mineralienatlas and Mindat , accessed on March 30, 2020.