Betechtinite
| Betechtinite | |
|---|---|
 |
|
| General and classification | |
| other names |
Betekhtinite |
| chemical formula | (Cu, Fe) 21 Pb 2 S 15 |
|
Mineral class (and possibly department) |
Sulfides and sulfosalts |
|
System no. to Strunz and to Dana |
2.BE.05 ( 8th edition : II / B.02) 02.16.08.01 |
| Similar minerals | Wittichenite |
| Crystallographic Data | |
| Crystal system | orthorhombic |
| Crystal class ; symbol | orthorhombic-dipyramidal; 2 / m 2 / m 2 / m |
| Space group | Immm (No. 71) |
| Lattice parameters | a = 14.67 Å ; b = 22.80 Å; c = 3.86 Å |
| Formula units | Z = 2 |
| Physical Properties | |
| Mohs hardness | 3 to 3.5 |
| Density (g / cm 3 ) | measured: 5.96 to 6.05; calculated: 6.14 |
| Cleavage | in three directions |
| colour | black |
| Line color | black |
| transparency | opaque |
| shine | Metallic luster |
Betechtinit (also Betekhtinit ) is a rarely occurring mineral from the mineral class of " sulfides and sulfosalts ". It crystallizes in the orthorhombic crystal system with the chemical composition (Cu, Fe) 21 Pb 2 S 15 . The elements copper and iron indicated in the round brackets can represent each other in the formula ( substitution , diadochie), but are always in the same proportion to the other components ( lead , sulfur ) of the mineral.
Betechtinite is opaque in every form and usually develops needle-like, shiny metallic crystals of black color with black streak color . Sanded samples are, however, of a rather light cream color parallel to the longitudinal direction or more yellowish-cream colored at right angles to it.
Etymology and history
Betechtinite was first described in 1955 by A. Schüller and E. Wohlmann, who named the mineral after the Soviet mineralogist Anatolii Georgievich Betekhtin (1897–1962). The type locality is the "Progress Shaft I" near Volkstedt (Eisleben) and the "Ernst-Thälmann Shaft" near Hübitz / Siersleben in the Mansfeld Basin (Saxony-Anhalt), as material from both sites was used to analyze the mineral composition.
Type material of the mineral is kept in the Mineral Museum of the Humboldt University in Berlin .
classification
In the meanwhile outdated, but still in use 8th edition of the mineral classification according to Strunz , the betechtinite belonged to the department of "sulfides, selenides and tellurides with a ratio of metal: S, Se, Te> 1: 1", where together with bornite , calvertite and Gortdrumit 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 assigns betechtinite to the division of "Metal sulfides, M: S> 1: 1 (mainly 2: 1)". However, this is 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 lead (Pb), bismuth (Bi)", where it is the only member of the unnamed group 2.BE .05 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns betechtinite to the class of "sulphides and sulphosalts" and there in the category of "sulphide minerals". Here he is to be found as the only member of the unnamed group 02.16.08 within the sub-section "Sulphides - including selenides and tellurides - with various formulas".
Crystal structure
Betechtinite crystallizes orthorhombically in the space group Immm (space group no. 71) with the lattice parameters a = 14.67 Å ; b = 22.80 Å and c = 3.86 Å and 2 formula units per unit cell .
Education and Locations
Betechtinit formed by hydrothermal processes in ore - deposits or in copper-containing shales . As Begleitminerale occur among others anhydrite , bornite , calcite , chalcocite , chalcopyrite , Celestine , galena and native silver on.
As a rare mineral formation, betechtinite could so far (status: 2013) only be detected at a few sites, whereby fewer than 40 sites are known. In addition to its type localities in the Mansfeld Basin, the mineral also appeared in Germany in the quarry at Wingertsberg near Nieder-Ramstadt and at the Emmertsberg quarry near Waschenbach in the Hessian community of Mühltal .
In Austria, the mineral was found in the “Haagen” mine near Webing and in the Erasmus tunnel near Schwarzleo (municipality of Leogang ) in Salzburg, and the only known site in Switzerland so far is Mürtschenalp in the Murg Valley in the canton of Glarus .
Kazakhstan , more precisely the copper mines in Schesqasghan ( Dzhezkazgan ), where rich crystal specimens with up to seven centimeters long bechtinite crystals have been found, is known for its extraordinary bechtinite finds .
Other locations include Argentina, Australia, Bulgaria, China, Greece, the Democratic Republic of the Congo, Namibia, Poland, Russia, Sweden, Scotland, the Czech Republic and the United States of America.
See also
literature
- A. Schüller, E. Wohlmann: Betechtinit, a new lead-copper sulfide from the Mansfeld ridge . In: Geology . tape 4 , 1955, pp. 535-555 .
- Friedrich Klockmann : Klockmann's textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp. 420 (first edition: 1891).
- 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. 348 .
Web links
- Mineral Atlas: Betechtinite (Wiki)
- Thomas Witzke : Discovery of Betekhtinite (Betechtinite)
- Mindat - Betekhtinite
- RRUFF Database-of-Raman-spectroscopy - Betekhtinite
Individual evidence
- ↑ 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. 74 .
- ↑ Webmineral - Betekhtinite
- ↑ a b Betekhtinite . 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; 60 kB ; accessed on August 14, 2017]).
- ^ Type mineral catalog of the University of Hamburg
- ↑ a b Petr Korbel, Milan Novák: Mineral Encyclopedia (= Dörfler Natur ). Nebel Verlag, Eggolsheim 2002, ISBN 978-3-89555-076-8 , p. 57 .
- ↑ Mindat - Number of localities for Betekhtinite
- ↑ Find location list for betechtinite at the Mineralienatlas and at Mindat