Germanite

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Germanite
Germanite.jpg
Germanite from Tsumeb, Otjikoto Region, Namibia
General and classification
chemical formula Cu 13 Fe 2 Ge 2 S 16
Mineral class
(and possibly department) 		Sulfides and sulfosalts
System no. to Strunz
and to Dana 		2.CB.30 ( 8th edition : II / C.10)
02.09.04.02
Crystallographic Data
Crystal system cubic
Crystal class ; symbol hexakistrahedral; 4 3 m
Room group (no.) P 4 3 n (No. 218)
Lattice parameters a  = 10.59  Å
Formula units Z  = 2
Physical Properties
Mohs hardness 4th
Density (g / cm 3 ) measured: 4.46 to 4.59; calculated: 4.30
Cleavage Please complete!
colour pink with a violet tinge, reddish gray
Line color grey black
transparency opaque
shine Metal gloss, matt
Other properties
Chemical behavior soluble in nitric acid

Germanite is a very seldom occurring mineral from the mineral class of " sulfides and sulfosalts ". It crystallizes in the cubic crystal system with the composition Cu 13 Fe 2 Ge 2 S 16 , so chemically speaking it is a copper - iron - germanium sulfide. In the miner's language , the mineral germanite falls under the pale ores .

Germanite is opaque in every form and is found predominantly in the form of massive or granular mineral aggregates with a metallic sheen on the surfaces, intergrown with renierite . However, idiomorphic crystals could also be observed under the microscope. Its color is usually pink or reddish gray with a clear tinge to violet, which after a while turns into a rich violet when it tarnishes .

Etymology and history

The mineral was first discovered and described in 1920 by Hans Schneiderhöhn in the type locality Tsumeb in Namibia , but not investigated in more detail. In 1921 W. Klein again found a mineral unknown to him in Tsumeb and sent it to the Berlin mineralogist Otto Hermann August Pufahl (1855-1924), who examined it more closely and determined its composition. He finally named the new mineral as germanite in 1922 after the element germanium it contained .

classification

In the Strunz system , germanite is a metal sulfide with a ratio of metal to sulfur, selenium or tellurium of 1: 1. After the 8th edition, it forms a group together with colusite , germanocolusite , maikainite , morozeviczite , nekrasovite , ovamboite , polkovicitite , renierite , stibiocolusite , sulvanite and vinciennite . In the 9th edition , it forms a subgroup of sulfides with zinc , iron , copper or silver with colusite, germanocolusite, maikainite, nekrasovite, ovamboite and stibiocolusite .

In the Dana systematics , it forms with renierite, maikainite and ovamboite a subgroup of sulfides, selenides and tellurides with the composition A m B n X p , with (m + n): p = 1: 1.

Crystal structure

Germanite crystallizes in the cubic crystal system in the space group P 4 3 n with the lattice parameter a = 10.59  Å and 2 formula units per unit cell .

properties

Germanite is difficult to melt and disintegrates when heated. It is soluble in nitric acid.

Education and Locations

Germanite forms in primary copper-lead-zinc ores. It is associated with renierite, pyrite , tennantite , enargite , galena , sphalerite , digigenite , bornite and chalcopyrite .

Only a few sites are known of the very rare mineral. In addition to the type locality, Germanite was found in Andalgalá in Argentina , Dastakert in Armenia , Panagjurischte in Bulgaria , the province of Pinar del Río in Cuba , Kipushi in the Democratic Republic of the Congo , Orivesi in Finland , Guillaumes in France , Laurion in Greece , Hida and other places in Japan , Niari in the Republic of the Congo , Magnitogorsk and other locations in Russia as well as the US states Alaska and Colorado .

See also

literature

Web links

Commons : Germanite  - 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.  80 .
  2. ↑ a b John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols: Germanite , in: Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 63.3 kB )
  3. ^ A b Helmut Schrätze, Karl-Ludwig Weiner: Mineralogie. A textbook on a systematic basis . de Gruyter, Berlin; New York 1981, ISBN 3-11-006823-0 , pp. 175 .
  4. ↑ Profile "Duftit" at steine-und-minerale.de with the full name of the person who first wrote it
  5. ↑ O. Pufahl: "Germanite", a germanium mineral and ore from Tsumeb, South West Africa (PDF; 273 kB). In: metal and ore . 1922, 13, pp. 324-325.
  6. ^ New Dana Classification of Sulfide Minerals