Vésigniéit
| Vésigniéit | |
|---|---|
 |
|
| General and classification | |
| chemical formula | BaCu 3 [OH | VO 4 ] 2 |
|
Mineral class (and possibly department) |
Phosphates, arsenates and vanadates |
|
System no. to Strunz and to Dana |
8.BH.45 ( 8th edition : VII / B.29) 05.41.13.01 |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic prismatic; 2 / m |
| Space group | C 2 / m (No. 12) |
| Lattice parameters |
a = 10.27 Å ; b = 5.91 Å; c = 7.71 Å β = 116.4 ° |
| Formula units | Z = 2 |
| Physical Properties | |
| Mohs hardness | 3 to 4 |
| Density (g / cm 3 ) | measured: 4.56 (10); calculated: 4.70 |
| Cleavage | perfect after {001}, imperfect after {110} |
| Break ; Tenacity | uneven |
| colour | yellow green, dark olive green |
| Line color | greenish |
| transparency | translucent |
| shine | Glass gloss to matt |
| Crystal optics | |
| Refractive indices |
n α = 2.053 n β = 2.129 n γ = 2.133 |
| Birefringence | δ = 0.080 |
| Optical character | biaxial negative |
| Axis angle | 2V = measured: 60 °; calculated: 24 ° |
Vésigniéit is a rarely occurring mineral from the mineral class of " phosphates , arsenates and vanadates ". It crystallizes in the monoclinic crystal system with the chemical composition BaCu 3 [OH | VO 4 ] 2 , so it is a barium - copper vanadate with additional hydroxide ions .
Vésigniéit is translucent and develops only small lamellar, pseudo-hexagonal crystals up to about two millimeters in size. It is usually found in the form of thin to coarse mineral aggregates or crusty to earthy powdery coatings. Its color varies between yellow-green and dark olive-green and its stroke color is also greenish. A glass-like gloss appears on the crystal surfaces , but aggregates or crusts are matt.
Etymology and history
Vésigniéit was first described in 1955 by Claude Guillemin , who named the mineral after the French mineral collector and President of the French Mineralogical Society Jean Paul Louis Vésignié (1870-1954). He had provided the sample material for determining the new mineral.
Guillemin discovered the new mineral on samples from Friedrichroda (Thuringia, Germany), which were designated as Calciovolborthite, and from the Urals (Russia), which were allegedly volborthite. Since most of the data were determined using the material from Friedrichroda, this is primarily the type locality for Vésigniéit, and the Urals as a co-type locality.
classification
Already in the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the vésigniéit belonged to the mineral class of "phosphates, arsenates and vanadates" and there to the department of "anhydrous phosphates, with foreign anions F, Cl, O, OH", where together with Bjarebyit , Drugmanit , Jagowerit , Johntomait , Kulanit , Penikisit and Perloffit, he created the "Bjarebyit Group" with the system no. VII / B.29 .
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 the Vésigniéit to the category of “Phosphates etc. with additional anions; without H 2 O “. However, this is further subdivided according to the relative size of the cations involved and the molar ratio of the other anions (OH etc.) to the phosphate, arsenate or vanadate complex (RO 4 ), so that the mineral can be classified in the sub-section “With medium-sized and mostly large cations; (OH etc.): RO 4 = 1: 1 ”is to be found where, together with Bayldonite, the“ Bayldonite group ”with the system no. 8.BH.45 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the vésigniéit to the class of "phosphates, arsenates and vanadates" and there to the category of "anhydrous phosphates etc., with hydroxyl or halogen". Here he is the only member of the unnamed group 41.05.13 within the sub-section “Anhydrous phosphates etc., with hydroxyl or halogen with (AB) 2 (XO 4 ) Z q ”.
Crystal structure
Vésigniéit crystallizes monoclinically in the space group C 2 / m (space group no. 12) with the lattice parameters a = 10.27 Å ; b = 5.91 Å; c = 7.71 Å and β = 116.4 ° and two formula units per unit cell .
Education and Locations
Vésigniéit forms secondarily in copper-containing uranium-vanadium deposits . As Begleitminerale among others can barite , calcite , Carnotit , malachite , Tyuyamunit and Volborthit occur.
As a rare mineral formation, Vésigniéit could only be proven at a few sites, whereby so far (as of 2013) around 45 sites are known. In Germany, in addition to its type locality Friedrichroda, the mine “Glücksstern” at Gottlob is also given as the exact location, including the mine Clara near Oberwolfach in Baden-Württemberg; near Bad Lauterberg in the Harz Mountains in Lower Saxony; in several places in the Eifel (Emmelberg, Rother Kopf, Kahlenberg) in Rhineland-Palatinate; can be found on the north coast of Heligoland in Schleswig-Holstein and in the manganese deposit near Ilfeld in Thuringia.
The only known site in the Urals in Russia is around the city of Perm in the region of the same name .
In Switzerland, Vésigniéit is only known from the Brunegg Glacier in the canton of Valais.
Other locations include Australia, the Democratic Republic of the Congo ( Zaire ), France, Italy, Mexico, Namibia, the Czech Republic, Ukraine, Uzbekistan, the United Kingdom (UK) and the United States of America (USA).
See also
literature
- Claude Guillemin: Une nouvelle espèce minérale: la vésigniéite Cu 3 Ba (VO 4 ) 2 (OH) 2 . In: Comptes Rendus de l'Academie des Sciences. Paris 1955, C 240, pp. 2331-2333
- Friedrich Klockmann : Klockmann's textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp. 634 (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. 645 .
- Petr Korbel, Milan Novák: Encyclopedia of Minerals . Dörfler Verlag GmbH, Eggolsheim 2002, ISBN 978-3-89555-076-8 , p. 168-169 .
Web links
- Mineral Atlas: Vésigniéit (Wiki)
- Thomas Witzke : The discovery of Vésigniéit. Retrieved September 22, 2013 .
- Gemmology.ch - Vésigniéite. Retrieved September 22, 2013 (French).
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. 460 .
- ↑ Webmineral - Vésigniéite.
- ↑ a b Vésigniéite. 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 64.3 kB)
- ↑ a b c d e Mindat - Vésigniéite
- ↑ Thomas Witzke : The discovery of Vésigniéit. Retrieved September 22, 2013 .
- ↑ Mindat - Number of localities for Vésigniéit
- ^ Artur Wittern: Mineral sites and their minerals in Germany . E. Schweizbart'sche Verlagsbuchhandlung, Stuttgart 2001, ISBN 3-510-65202-9 , pp. 128-129 .
- ↑ List of localities for Vésigniéite in the Mineralienatlas and Mindat