Argento treehouseite
| Argento treehouseite | |
|---|---|
 |
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| General and classification | |
| other names |
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| chemical formula |
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Mineral class (and possibly department) |
Sulfides and sulfosalts |
|
System no. to Strunz and to Dana |
2.HC.05b 03.06.13.02 |
| Similar minerals | Baumhauerite |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic prismatic; 2 / m |
| Lattice parameters |
a = 44.74 Å ; b = 8.48 Å; c = 7.91 Å β = 93.4 ° |
| Formula units | Z = 8 |
| Physical Properties | |
| Mohs hardness | 3 |
| Density (g / cm 3 ) | calculated: 5.31 to 5.37 |
| Cleavage | completely after {100} |
| Break ; Tenacity | shell-like |
| colour | steel gray |
| Line color | reddish brown |
| transparency | opaque |
| shine | Metallic luster |
Argentobaumhauerite (formerly Baumhauerit-2a ) is a very rare mineral from the mineral class of " sulfides and sulfosalts ". It crystallizes in the monoclinic crystal system with the chemical composition Ag 1.5 Pb 22 As 33.5 S 72 .
Up until now, argentobaumhauerite could only be found in the form of microscopic crystals and adhesions with Baumhauerite. It is opaque in every form and has a steel-gray, metallic glossy color with a reddish-brown line color .
Etymology and history
Baumhauerit-2a was first discovered in the "Grube Lengenbach" in the Binntal (canton Valais) in Switzerland. The mineral was scientifically described in 1990 by Allan Pring, William D. Birch, David Sewell, Stefan Graeser, Andreas Edenharter and Alan Criddle, who named it after the professor of mineralogy H. A. Baumhauer (1848–1926) at the University of Freiburg (Switzerland) . The 2a contained in the name is due to a doubled crystal lattice constant in contrast to Baumhauerite .
In 2015 the mineral was renamed to argentobaumhauerite and the renaming was recognized by the International Mineralogical Association (IMA) (IMA No. 15-F).
Type material of the mineral was found in the Museum of Victoria in Melbourne (register no. M30980), in the South Australian Museum in Adelaide (register no. G15547), in the Natural History Museum in London (register no. 1926, 1654) and in natural history Museum Basel (register no. L7228).
classification
Since the argentobaumhauerite was not recognized and published as an independent mineral until 1990, it is not listed in the outdated 8th edition of the mineral classification according to Strunz . Only in the "Lapis Mineral Directory", which was last updated in 2018 and which, out of consideration for private collectors and institutional collections, is still based on this classic systematics by Karl Hugo Strunz, was Argentobaumhauerite given the system and mineral no. II / E.24-15. In the “Lapis system” this corresponds to the section “Sulphosalts (S: As, Sb, Bi = x” with x = 2.3–1.8,) where, together with Baumhauerite , Bernarlottiite and Robinsonite, it is an independent but unnamed Group forms.
The 9th edition of Strunz's mineral systematics , which has been valid since 2001 and was last updated in 2009 by the International Mineralogical Association (IMA), also assigns argentobaumhauerite to the class of "sulfides and sulfosalts" and there in the department of "sulfosalts with SnS as a model" a. 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 “Only with lead (Pb)”, where it is found together with Baumhauerite (formerly Baumhauerit I ) and the one previously considered questionable Baumhauerit II the "Baumhauerite group" with the system no. 2.HC.05b forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns argentobaumhauerite to the class of "sulfides and sulfosalts" and there in the department of "sulfosalts". Here it is together with Baumhauerite in the unnamed group 06/03/13 within the subdivision of “Sulphosalts with the ratio 2.0 <z / y <2.49 and the composition (A + ) i (A 2+ ) j [B y C z ], A = metals, B = semimetals, C = non-metals ”.
Crystal structure
Argentobaumhauerite crystallizes monoclinically, whereby the space group has not yet been determined. The lattice parameters are a = 44.74 Å ; b = 8.48 Å; c = 7.91 Å and β = 93.4 ° and 8 formula units per unit cell .
Education and Locations
Argentobaumhauerite forms together with Baumhauerite through hydrothermal processes in dolomite rock . Other lead sulfoarsenides as well as pyrite and realgar occur as accompanying minerals in addition to treehouserite and dolomite .
Apart from its type locality “Grube Lengenbach” in Switzerland, only the “Quiruvilca Mine” near Quiruvilca ( Province of Santiago de Chuco ) in the Peruvian region of La Libertad is known as a site for argentobaumhauerite (as of 2012) .
See also
literature
- Allan Pring, William D. Birch, David Sewell, Stefan Graeser, Andreas Edenharter, Alan Criddle: Baumhauerite-2a: A silver-bearing mineral with a baumhauerite-like supercell from Lengenbach, Switzerland . In: American Mineralogist . tape 75 , 1990, pp. 915–922 ( available online at rruff.info [PDF; 829 kB ; accessed on March 31, 2019]).
Web links
- Mineral Atlas: Argentobaumhauerite (Wiki)
- Argento Treesite search results. In: rruff.info. Database of Raman spectroscopy, X-ray diffraction and chemistry of minerals (RRUFF), accessed on March 31, 2019 .
Individual evidence
- ↑ a b Malcolm Back, William D. Birch, Michel Blondieau and others: The New IMA List of Minerals - A Work in Progress - Updated: November 2018. (PDF 1753 kB) In: cnmnc.main.jp. IMA / CNMNC, Marco Pasero, November 2018, accessed March 31, 2019 .
- ↑ Allan Pring, William D. Birch, David Sewell, Stefan Graeser, Andreas Edenharter, Alan Criddle: Baumhauerite-2a: A silver-bearing mineral with a baumhauerite-like supercell from Lengenbach, Switzerland . In: American Mineralogist . tape 75 , 1990, pp. 915–922 ( available online at rruff.info [PDF; 829 kB ; accessed on March 31, 2019]).
- ↑ a b c Baumhauerite-2a . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 ( available online at handbookofmineralogy.org [PDF; 62 kB ; accessed on March 31, 2019]).
- ^ A b c 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. 134 (English).
- ↑ David Barthelmy: Baumhauerite-2a Mineral Data. In: webmineral.com. Retrieved May 2, 2020 .
- ↑ U. Hålenius, F. Hatert, M. Pasero, SJ Mills: IMA Commission on New Minerals, Nomenclature and Classification (CNMNC). Newsletter 25 . In: Mineralogical Magazine . tape 79 , no. 3 , June 2015, p. 529–535 ( available online at rruff.info [PDF; 86 kB ; accessed on March 31, 2019]).
- ↑ 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 .
- ↑ Argento tree tuskite. In: mindat.org. Hudson Institute of Mineralogy, accessed March 31, 2019 .