Uytenbogaardtite
| Uytenbogaardtite | |
|---|---|
 |
|
| General and classification | |
| other names |
|
| chemical formula | Ag 3 AuS 2 |
|
Mineral class (and possibly department) |
Sulfides and sulfosalts |
|
System no. to Strunz and to Dana |
2.BA.40b ( 8th edition : II / B.07) 04/02/03/01 |
| Crystallographic Data | |
| Crystal system | tetragonal |
| Crystal class ; symbol | tetragonal-trapazohedral 422 or tetragonal-pyramidal 4 |
| Room group (no.) | P 4 1 22 or P 4 1 (No. 91 or 76) |
| Lattice parameters | a = 9.68 Å ; c = 9.81 Å |
| Formula units | Z = 8 |
| Physical Properties | |
| Mohs hardness | ≈ 2 (VHN 15 ≈ 20) |
| Density (g / cm 3 ) | calculated: 8.34 to 8.45 |
| Cleavage | Please complete |
| Break ; Tenacity | significantly more brittle than acanthite |
| colour | gray-white in polished sections |
| Line color | not defined |
| transparency | opaque |
| shine | Metallic luster |
Uytenbogaardtite is a rarely occurring mineral from the mineral class of "sulfides and sulfosalts". It crystallizes in the tetragonal crystal system with the chemical composition Ag 3 AuS 2 , making it a silver - gold - sulphide .
Uytenbogaardtite is opaque and has so far only been discovered in the form of microcrystalline, shiny metallic inclusions , including in acanthite . The exact mineral color has not yet been determined, but under the reflected light microscope the mineral appears gray-white in polished sections.
Etymology and history
Uytenbogaardtit was first described in 1978 by MD Barton, C. Kieft, EAJ Burke and ID Oen, who named the mineral after the Dutch professor of geology at the Technical University of Delft Willem Uytenbogaardt (1918-2012).
The mineral was first discovered at Tambang Sawah in the Rejang Lebong administrative district in the Bengkulu province on the Indonesian island of Sumatra , in the Comstock Lode ore deposit in Storey County in the US state of Nevada and on Schlangenberg near the town of Smeinogorsk in the Altai region (southern western Siberia ) in Russia . All three sites are therefore considered a type locality for Uytenbogaardtite.
Type material of the mineral is stored in the Institute of Geosciences of the Free University of Amsterdam and the University of Amsterdam in the Netherlands and in the National Museum of Natural History in Washington DC in the USA (catalog no. 105328, B239).
classification
Already in the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the Uytenbogaardtite belonged to the mineral class of "sulfides and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 he together with Criddleit , Fischesserit , Muthmannit , Penzhinit , Petrovskait and petzite the unnamed group II / B.07 formed.
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 Uytenbogaardtite in the category of "Metal sulfides, M: S> 1: 1 (mainly 2: 1)". However, this is further subdivided according to the metals involved in the connection, so that the mineral can be found according to its composition in the sub-section "with copper (Cu), silver (Ag), gold (Au)", where it is the only member forms unnamed group 2.BA.40b .
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns Uytenbogaardtite to the class of "sulfides and sulfosalts" and there in the department of "sulfide minerals". Here he is the namesake in the " Uytenbogaardtitgruppe " with the system no. 04/02/03 and the other members Fischesserit and Petzit can be found within the subsection "Sulphides - including selenides and tellurides - with the composition A m B n X p , with (m + n): p = 2: 1".
Education and Locations
Uytenbogaardtite forms in low grade hydrothermal gold-silver quartz - veins where it mostly in paragenesis with Akanthit , Chlorargyrite , various gold-silver alloy ( electrum ) and Naumannite occurs.
As a rare mineral formation, Uytenbogaardtite could only be detected at a few sites, with around 35 sites known so far (as of 2014).
In Indonesia, the mineral was found in the Cirotan mine near Cikotok and in the Gunung Pongkor mine near Bogor on the island of Java, in addition to its type locality Tambang Sawah on Sumatra .
In Russia uytenbogaardtite came apart at its type locality Schlangenberg at zmeinogorsk in Western Siberia still in the deposit Khopto in the eastern Siberian republic of Tuva , in the deposit Kupol in the Autonomous District of the Chukchi in the Far Eastern Federal District and in the copper-zinc deposit Gayskoe ( Gayskoye , Gaiskoye ) near the town of Gai ( Gay ) in the Orenburg Oblast (Urals).
In the US state of Nevada, in addition to its type locality Comstock Lode in Storey County, the mineral was also found in the Dean Mine (Cumberland Mine) near Lewis in Lander County and at various sites in the Bullfrog District , the Bullfrog Hills and the Tolicha District in the Nye County to be discovered.
Other locations are in Argentina, Bolivia, China, Malaysia, New Zealand, Peru, Romania, Slovakia and in the US states of Arizona, Colorado and California.
Crystal structure
Uytenbogaardtite crystallizes tetragonally in the space group P 4 1 22 or P 4 1 (space group no. 91 or 76) with the lattice parameters a = 9.68 Å and c = 9.81 Å as well as 8 formula units per unit cell .
See also
literature
- MD Barton, C. Kieft, EAJ Burke, ID Oen: Uytenbogaardtite, a new silver-gold sulfide. In: The Canadian Mineralogist. Volume 16, 1978, pp. 651-657 ( PDF 1.12 MB ).
- 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. 302 .
Web links
- Mineral Atlas: Uytenbogaardtit (Wiki)
- Mindat - Uytenbogaardtite
- Webmineral - Uytenbogaardtite
- American-Mineralogist-Crystal-Structure-Database - Uytenbogaardtite
Individual evidence
- ↑ 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. 67 .
- ↑ a b c Uytenbogaardtite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 ( PDF 60.2 kB ).
- ↑ Mindat - Number of localities for Uytenbogaardtit
- ↑ Find location list for Uytenbogaardtite at the Mineralienatlas and at Mindat