Arsentsumebit
| Arsentsumebit | |
|---|---|
 |
|
| General and classification | |
| chemical formula | Pb 2 Cu [OH | SO 4 | AsO 4 ] |
|
Mineral class (and possibly department) |
Phosphates, arsenates and vanadates |
|
System no. to Strunz and to Dana |
8.BG.05 ( 8th edition : VII / B.24) 04.43.02.02 |
| Similar minerals | Tsumebit |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic prismatic; 2 / m |
| Room group (no.) | P 2 1 / m (No. 11) |
| Lattice parameters |
a = 8.85 Å ; b = 5.92 Å; c = 7.84 Å β = 112.6 ° |
| Formula units | Z = 12 |
| Physical Properties | |
| Mohs hardness | 4 to 5 |
| Density (g / cm 3 ) | measured: 6.46; calculated 6.39 |
| Cleavage | brittle |
| Break ; Tenacity | uneven |
| colour | blue-green, yellow-green, emerald green to light green |
| Line color | light green |
| transparency | translucent |
| shine | Glass gloss to diamond gloss, matt |
| Crystal optics | |
| Refractive indices |
n α = 1.970 n β = 1.992 n γ = 2.011 |
| Birefringence | δ = 0.041 |
| Optical character | biaxial negative |
| Axis angle | 2V = measured: 88 °; calculated: 84 ° |
| Pleochroism | visible: X = light to pistachio green; Y = Z = bottle green |
Arsentsumebit is a very rare mineral from the mineral class " phosphates , arsenates and vanadates ". It crystallizes in the monoclinic crystal system with the chemical composition Pb 2 Cu [OH | SO 4 | AsO 4 ] and develops only small, translucent crystals up to about 2 mm in size in earthy to massive aggregates or crusty coatings of blue-green, yellow-green or emerald-green to light green in color with light green line color .
Etymology and history
The name Arsentsumebit indicates on the one hand its first place of discovery ( type locality ) Tsumeb and on the other hand one of its main components arsenic , which distinguishes the Arsentsumebit from the Tsumebit . It was first discovered and described in 1935 by the French colonel, mineral collector and researcher Jean Paul Louis Vésignié (1870–1954).
classification
In the meanwhile outdated, but still in use 8th edition of the mineral systematics according to Strunz , the arsentsumebite belonged to the mineral class of "phosphates, arsenates and vanadates" and there to the department of "anhydrous phosphates with foreign anions ", where it together with arsenic brackebuschit , bearthite , brackebuschite , Bushmakinit , Calderónit , Feinglosit , Gamagarit , Goedkenit , Jamesit , Lulzacit , Tokyoit and tsumebite the "Brackebuschit group" with the system number. VII / B.24 .
The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), assigns arsentsumebite to the class of “phosphates, arsenates and vanadates” and there to the department of “phosphates, etc. with additional anions; without H 2 O “. However, this section is further subdivided according to the size of the cations involved and the molar ratio between the other anions (OH etc.) and the main anion complex RO 4 , so that the mineral is classified in the sub-section “With medium-sized and large cations; (OH etc.): RO 4 = 0.5: 1 "can be found, where the" brackebuschite group "is also found together with arsenic brackebuschite, bearthite, brackebuschite, bushmakinite, calderónite, feinglosite, gamagarite, Goedkenit, Tokyoite and tsumebit the system no. 8.BG.05 forms.
The systematics of minerals according to Dana also assigns arsentsumebit to the class of "phosphates, arsenates and vanadates" and there in the department of "phosphates". Here it is only together with tsumebit in the "tsumebit group" with the system no. 43.04.02 within the subsection of " Compound phosphates etc., (anhydrous compound anions with hydroxyl or halogen) ".
Education and Locations
Tsumebite is a secondary mineral that forms in the oxidation zones of lead and copper deposits and is created there by substitution from mimetite . In Tsumeb there are also pseudomorphoses (assumed crystal form of another mineral) according to azurite . In addition to mimetesite and azurite, accompanying minerals include angelsite , bayldonite , cerussite , conichalcite , malachite and smithsonite .
So far, Arsentsumebit has been detected at around 25 sites worldwide (as of 2011). In Germany, the mineral was found in the Clara mine near Oberwolfach, the Glücksrad mine in the community of Schulenberg in the Upper Harz , the Wilder Mann mine near Müsen, near Bad Ems in the Lahn valley and near Raubschloss (Gräfenroda) .
Other locations are Broken Hill (New South Wales) and Ashburton Shire (Western Australia) in Australia; the copper deposit near Zapachitsa in the Bulgarian municipality of Swoge ; Moldava ( Moldau ) in the Czech Republic; the French communes of Ébreuil , Padern , Le Pradet and Les Ardillats (Département Rhône); Lavrio (Lavrion) in Greece; Wethel in Powys, Welsh (Great Britain); as well as the Inyo Mountains in Inyo County , the John Long Mountains in Granite County , the Gallinas Mountains in Lincoln County, New Mexico, and Gold Hill in Tooele County in the United States.
Crystal structure
Arsentsumebit crystallizes monoclinically in the space group P 2 1 / m (space group no. 11) with the lattice parameters a = 8.85 Å ; b = 5.92 Å; c = 7.84 Å and β = 112.6 ° as well as 2 formula units per unit cell .
use
Like tsumebite, arsentsumebite has no economic significance except as a mineral sample.
See also
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. 453 .
- ↑ Webmineral - Arsentsumebite (English)
- ↑ Arsentsumebite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 63.3 kB )
- ↑ a b c d Mindat - Arsentsumebite (English)
- ↑ Collection Mineralogique, Don Giovanni Zingo - Arsentsumebite (French: Découvert en 1935 ans la mine Tsumeb à Tsumeb, district d'Otavi-Bergland, Région d'Oshjkoto, Namibie, par le français Louis Vesignie (1870-1954) ... )
- ↑ Handbook of Mineralogy - Vésigniéite (English, PDF 64.3kB; named after Jean Paul Louis Vésignié (1870–1954))
literature
- Petr Korbel, Milan Novák: Encyclopedia of Minerals . Nebel Verlag GmbH, Eggolsheim 2002, ISBN 3-89555-076-0 .
