Trogtalit

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Trogtalit
Oosterboschite, Trogtalite, Cuprosklodowskite, Quartz-384830.jpg
Brown weathered trogtalite crystals in a quartz matrix with oosterboschite (gray crystals below) and cuprosklodovskite (green)
General and classification
other names

Cobalt selenide

chemical formula CoSe 2
Mineral class
(and possibly department) 		Sulfides and sulfosalts (including selenides, tellurides, arsenides, antimonides, bismuthides, sulfarsenides, sulfantimonides, sulfbismuthides)
System no. to Strunz
and to Dana 		2.EB.05a ( 8th edition : II / C.05)
02.12.01.05
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  = 5.86  Å
Formula units Z  = 4
Physical Properties
Mohs hardness ≈ 7
Density (g / cm 3 ) measured: 7.09 (synthetic); calculated: 7.12
Cleavage not defined
colour pink violet
Line color not defined
transparency opaque (opaque)
shine Metallic luster

Trogtalite is a seldom occurring mineral from the mineral class of "sulfides and sulfosalts" with the chemical composition CoSe 2 and thus, chemically speaking, cobalt diselenide .

Trogtalite crystallizes in the cubic crystal system , but has so far only been found in the form of microscopic, irregular grains up to about one millimeter in size and grown in Clausthalite . The surfaces of the mineral, which is opaque in every form and pink-violet in fresh samples, has a metallic sheen .

With a Mohs hardness of 7, trogtalite is one of the hard minerals and, if it were of the appropriate size, would be able to scratch window glass, similar to the reference mineral quartz .

Etymology and history

As early as 1928, WF de Jong and HWV Willems succeeded in synthesizing the compound CoSe 2 and clarifying the crystal structure .

Natural mineral formation was Trogtalit together with Bornhardtit , Hastit (discredited identical to Ferroselit) and a first unnamed cobalt selenide in grauwacke -Steinbruch Trogtal near Lautenthal discovered in the Lower Saxony district Goslar. The first description was in 1955 by Paul Ramdohr and Marg. Schmitt, who named the mineral after its type locality . The mineral, which was still unnamed at the time due to a lack of measurement results, was identified as cobalt selenide (CoSe) by Hugo Strunz in 1957 and was given the name Freboldite .

The type material of the mineral is in the Natural History Museum in London, England, under catalog no. 1980,400 and in the National Museum of Natural History in Washington, DC, USA under catalog no. 112811 kept.

classification

Already in the outdated 8th edition of the mineral classification according to Strunz , the trogtalite belonged to the mineral class of "sulfides and sulfosalts" and there to the department of "sulfides with M: S <1: 1", where it together with Aurostibit , Cattierit , Geversit , Hauerit , Laurite , michenerite , penroseit , pyrite , sperrylite , vaesite and villamanínite the "pyrite series" with the system no. II / C.05 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.17-50 . In the "Lapis system" this also corresponds to the section "Sulphides with metal: S, Se, Te <1: 1", where Trogtalite together with Aurostibite, Cattierite, Changchengit , Dzharkenite , Erlichmanite , Fukuchilit , Geversit, Hauerite, Insizwait , Krutaite , Laurit, Maslovit , Mayingit , Michenerit, Padmait , Penroseite, pyrite, Sperrylith, Testibiopalladit , Vaesit and Villamanínit the "pyrite group" formed (as 2018).

The 9th edition of Strunz's mineral systematics, which has been valid since 2001 and updated by the International Mineralogical Association (IMA) until 2009, classifies the trogtalite in the more general section of "Metal sulfides with M: S ≤ 1: 2". However, 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." according to its composition where it together with Aurostibit, cattierite, Dzharkenit, Erlichmanit, Fukuchilit, Gaotaiit , Geversit, Hauerit, Insizwait, Iridisit , Krutaite, Laurit, Penroseite, pyrite, Sperrylith, Vaesit and Villamanínit the "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 the trogtalite to the class of "sulfides and sulfosalts" and there in the department of "sulfide minerals". Here it is also 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

Chemism

According to the idealized (theoretical) composition of trogtalite (CoSe 2 ), the mineral consists of 27.18% cobalt (Co) and 72.82% selenium (Se). When analyzing trogtalite samples from the Musonoi mine near Kolwezi (Democratic Republic of the Congo), however, significant contents of copper (Cu, 9.02%) and palladium (Pd, 4.67%) could be determined.

Crystal structure

Trogtalite crystallizes cubically in the pyrite structure in the space group Pa 3 (space group no. 205) with the lattice parameter a  = 5.86  Å and 4 formula units per unit cell . Template: room group / 205

Education and Locations

Trogtalite forms alongside other Co-Se minerals grown in Clausthalite in selenium-bearing corridors . Bornhardtite , Oosterboschite as well as solid gold and selenium have appeared as accompanying minerals so far .

As a rare mineral formation, Trogtalite is only known from a few localities, with slightly more than 10 localities being documented so far. In addition to its type locality in the Trogtal quarry near Lautenthal, the mineral also appeared in Lower Saxony in the Roter Bär and Wennsglück pits on the Beerberg . Other well-known sites in Germany are an unnamed Grauwacke quarry near Rieder (Ballenstedt) in the Harz district and some pingen , heaps and small quarries near Tilkerode in the Mansfeld southern Harz in Saxony-Anhalt and the Friedrichsglück mine in the Tannenglasbachsgrund near Neustadt am Rennsteig in Thuringia.

Other previously known sites include the Tumiñico mine near Villa Castelli and Los Llantenes in the Vinchina department in the La Rioja province as well as the Sierra de Cacheuta near Cacheuta in the Mendoza province in Argentina, the El Dragón mine in the Bolivian province of Antonio Quijarro , the Shinkolobwe mine in the province of Haut-Katanga and the Musonoi mine in the province of Lualaba in the Democratic Republic of the Congo and the Předbořice uranium deposit with anomalous accumulations of uraninite , selenide and gold near Předbořice in the Czech municipality of Kovářov (Central Bohemia).

Trivia

In the science fiction series Star Trek: Deep Space Nine , fictional “cobalt diselenide” synthesized from selenium and rhodium nitrite is used as a nerve gas , which is harmless to most humanoids, but fatal to Cardassians .

See also

literature

  • WF de Jong, HWV Willems: Connections FeSe 2 , CoSe 2 and NiSe 2 . In: Journal of Inorganic and General Chemistry . tape 170 , 1928, pp. 241–245 ( rruff.info [PDF; 188 kB ; accessed on March 6, 2020]).
  • Paul Ramdohr , Marg. Schmitt: Four new natural cobalt selenides from the Trogtal quarry near Lautenthal in the Harz Mountains . In: New yearbook for mineralogy, monthly books . tape 6 , 1955, pp. 133-142 .
  • Michael Fleischer : New mineral names . In: American Mineralogist . tape 41 , 1956, pp. 163–168 (English, rruff.info [PDF; 326 kB ; accessed on March 6, 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 (first edition: 1891).

Web links

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

Individual evidence

  1. ↑ a b c d e 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 (English).
  2. ↑ Malcolm Back, William D. Birch, Michel Blondieau and others: The New IMA List of Minerals - A Work in Progress - Updated: March 2020. (PDF 1729 kB) In: cnmnc.main.jp. IMA / CNMNC, Marco Pasero, March 2020, accessed March 6, 2020 .
  3. ↑ a b c d e Trogtalite . 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 6, 2020]).
  4. ↑ WF de Jong, HWV Willems: Compounds FeSe 2 , CoSe 2 and NiSe 2 . In: Journal of Inorganic and General Chemistry . tape 170 , 1928, pp. 241–245 ( rruff.info [PDF; 188 kB ; accessed on March 6, 2020]).
  5. ^ Hugo Strunz : Mineralogical tables . 3. Edition. Geest & Portig, Leipzig 1957, p.  98 (NiAs-type and related: Freboldite).
  6. ↑ Michael Fleischer : New mineral names . In: American Mineralogist . tape  44 , 1959, pp. 906–910 (English, rruff.info [PDF; 377 kB ; accessed on March 9, 2020]).
  7. ↑ 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 .
  8. ↑ Ernest H. Nickel, Monte C. Nichols: IMA / CNMNC List of Minerals 2009. (PDF 1816 kB) In: cnmnc.main.jp. IMA / CNMNC, January 2009, accessed March 6, 2020 .
  9. ^ David Barthelmy: Trogtalite Mineral Data. In: webmineral.com. Retrieved March 6, 2020 .
  10. ↑ Find location list for trogtalite in the Mineralienatlas and Mindat , accessed on March 5, 2020.
  11. ^ Roggan and others: Cobalt Diselen. In: /memory-alpha.fandom.com. 2007, accessed March 9, 2020 .