Imiterite

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Imiterite
Imiterite with Proustite on Quartz - Imiter-Mine, Quarzazate, Marocco.jpg
Needle-like imiterite as a drusen filling from the type locality Imiter-Mine, Ouarzazate, Morocco
General and classification
other names

IMA 1983-038

chemical formula Ag 2 HgS 2
Mineral class
(and possibly department) 		Sulfides and sulfosalts
System no. to Strunz
and to Dana 		2.BD.05 ( 8th edition : II / B.06)
02.05.08.01
Crystallographic Data
Crystal system monoclinic
Crystal class ; symbol monoclinic prismatic; 2 / m
Room group (no.) P 2 1 / c (No. 14)
Lattice parameters a  = 4.04  Å ; b  = 8.01 Å; c  = 6.58 Å
β  = 107.1 °
Formula units Z  = 2
Physical Properties
Mohs hardness 2.5 (VHN 100 = 86)
Density (g / cm 3 ) calculated: 7,846 (4)
Cleavage not defined
Break ; Tenacity not defined
colour light gray, silver gray, steel gray, black
Line color dark gray
transparency opaque
shine strong metallic luster

Imiterite is a very rarely occurring mineral from the mineral class of " sulfides and sulfosalts ". It crystallizes in the monoclinic crystal system with the chemical composition Ag 2 HgS 2 , so it is a silver - mercury sulfide.

Imiterite is opaque in every form and only develops small, needle-like crystals up to about one centimeter in length with a strong metallic sheen on the surfaces. It is mostly found in the form of irregular grains and in mineral aggregates . Its color varies between light gray, silver gray and steel gray to black.

Etymology and history

Imiterite was first discovered in the silver ore open pit "Imiter" (Imiter Mine) near Boumalne Dadès in the Moroccan province of Ouarzazate and described in 1985 by JJ Guillou, J. Monthel, P. Picot, F. Pillard, J. Protas and JC Samama, the named the mineral after its type locality .

The type material of the mineral is kept in the Bureau de recherches géologiques et minières (BRGM) in Orléans and the Mines ParisTech (École des mines de Paris) in France.

The original spelling Imitérit (French Imitérite ), which was originally chosen by the first writers , has been discredited since 2008, as the eponymous opencast mine is written without an acute above the 'e' and it is therefore an unnecessary diacritical mark .

classification

Already in the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the imiterite belonged to the mineral class of "sulfides and sulfosalts" and there to the department of "sulfides, selenides and tellurides with the molar ratio metal: S, Se, Te> 1 : 1 “, where together with Brodtkorbit , Eukairit , Henryit , Jalpait , Mckinstryit , Selenojalpait and Stromeyerit it formed the unnamed group II / B.06 .

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 the imiterite in the category of "Metal sulfides, M: S> 1: 1 (mainly 2: 1)". However, this is further subdivided according to the metals occurring in the compound, so that the mineral can be found according to its composition in the sub-section "with mercury (Hg), thallium (Tl)", where it is the only member of the unnamed group 2.BD .05 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the imiterite to the class of "sulfides and sulfosalts" and there in the department of "sulfide minerals". Here it can be found together with Brodtkorbite in the unnamed group 02.05.08 within the subsection “Sulphides - including selenides and tellurides - with the composition A m B n X p , with (m + n): p = 3: 2”.

Education and Locations

Close-up of imiterite needles from the Imiter mine, Morocco (field of view 5 mm)
Imiterite (silvery needles) on Proustite (dark red) from the Imiter mine ( total size : 5.8 cm × 3.6 cm × 2.7 cm)

Imiterit forms in hydrothermal - veins pyrithaltiger deposits , where he next pyrite or with other sulphide minerals such as Akanthit , arsenopyrite , chalcopyrite , galena , marcasite , Polybasit and sphalerite but also with common carbonate calcite associated can be.

As a rare mineral formation, imiterite could only be detected at a few sites, whereby so far (as of 2013) a little more than 10 sites are known. In addition to its type locality, the “Imiter” open-cast mine, the mineral has only been found in Morocco in the nearby “Igoudrane” mine in the Jbel Sarhro Mountains.

In Germany, imiterite has so far been found in a gabbro quarry near Nieder-Beerbach in Hesse and the "Alexander" and "Dörnberg" pits near Ramsbeck in the North Rhine-Westphalian Hochsauerlandkreis.

The only known site in Austria so far is Ruden in the Astental in the Goldberg Group in Carinthia.

Other previously known sites are the “San Giovanni Mine” near Punta della Torre in the Italian province of Carbonia-Iglesias (Sardinia), the “Andrássy III. Mine ”in the Hungarian municipality of Rudabánya , the“ Lill ”mine near Březové Hory and Jáchymov in Bohemia as well as the“ Golden Rule Mine ”near Jamestown in Tuolumne County (California) and the“ Geis Mine ”near Cone Butte in Fergus County (Montana) in the United States of America (USA).

Crystal structure

Imiterite crystallizes monoclinically in the space group P 2 1 / c (space group no. 14) with the lattice parameters a  = 4.04  Å ; b  = 8.01 Å; c  = 6.58 Å and β = 107.1 ° as well as two formula units per unit cell .

See also

literature

  • JJ Guillou, J. Monthel, P. Picot, F. Pillard, J. Protas, JC Samama: L'imitérite, Ag 2 HgS 2 , nouvelle espèce minérale; propriétés et structure cristalline. In: Bulletin de Minéralogie. 108: 457-464 (1985)
  • Frank C. Hawthorne, Michael Fleischer, Edward S. Grew, Joel D. Grice, John L. Jambor, Jacek Puziewicz, Andrew C. Roberts, David A. Vanko, Janet A. Zilczer: New mineral names. In: American Mineralogist. Volume 71 (1986), pp. 1277–1282 ( PDF 625.4 kB ; Imiterit pp. 1–2)

Web links

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

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.  72 .
  2. ↑ a b Stefan Weiß: The large Lapis mineral directory. All minerals from A - Z and their properties . 5th completely revised and supplemented edition. Weise, Munich 2008, ISBN 978-3-921656-70-9 .
  3. ↑ a b c Imiterit , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 62.6 kB )
  4. ^ Ernst AJ Burke: Tidying up Mineral Names: an IMA-CNMNC Scheme for Suffixes, Hyphens and Diacritical marks , In: Mineralogical Record , Volume 39, No. 2 (March – April 2008); PDF 2.7 MB
  5. ↑ Mindat - Number of localities for imiterite
  6. ↑ Find location list for imiterite in the Mineralienatlas and Mindat