Vauquelinite
| Vauquelinite | |
|---|---|
 |
|
| General and classification | |
| other names |
|
| chemical formula | Pb 2 Cu [OH | PO 4 | CrO 4 ] |
|
Mineral class (and possibly department) |
Sulfates (including selenates, tellurates, chromates, molybdates, and tungstates) |
|
System no. to Strunz and to Dana |
7.FC.05 ( 8th edition : VI / F.02) 04/43/03/01 |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic prismatic; 2 / m |
| Space group | P 2 1 / n (No. 14, position 2) |
| Lattice parameters |
a = 13.75 Å ; b = 5.81 Å; c = 9.56 Å β = 94.6 ° |
| Formula units | Z = 4 |
| Twinning | after {102} |
| Physical Properties | |
| Mohs hardness | 2.5 to 3 |
| Density (g / cm 3 ) | measured: 6.16; calculated: 6.16 |
| Cleavage | indistinct |
| Break ; Tenacity | uneven; brittle |
| colour | apple, siskin or olive green, canary yellow, ocher brown, liver brown to almost black |
| Line color | greenish to brownish |
| transparency | translucent, transparent in thin layers |
| shine | Resin gloss to diamond gloss |
| Crystal optics | |
| Refractive indices |
n α = 2.110 n β = 2.220 n γ = 2.220 |
| Birefringence | δ = 0.110 |
| Optical character | biaxial negative |
| Pleochroism | visible: X = light green, Y = Z = light brown |
| Other properties | |
| Chemical behavior | soluble in nitric acid |
Vauquelinite is a rarely occurring mineral from the mineral class of "sulfates (including selenates, tellurates, chromates, molybdates and tungstates)" with the chemical composition Pb 2 Cu [OH | PO 4 |} CrO 4 ] and is therefore chemically a lead - Copper - chromate with hydroxide and phosphate ions as additional anions .
Vauquelinite crystallizes in the monoclinic crystal system , but develops only small, wedge-shaped crystals and twins up to about five millimeters in length with a resin-like to diamond-like sheen on the surfaces. Usually it occurs in the form of bulbous, kidney, grape, granular or massive mineral aggregates and crusty coatings. Its color varies between green and brown in different variations from apple, siskin and olive green to canary yellow and ocher brown or liver brown to almost black. Its line color is also greenish to brownish.
With a Mohs hardness of 2.5 to 3, vauquelinite is one of the soft to medium-hard minerals and is slightly easier to scratch with a copper coin than the reference mineral calcite (3).
Etymology and history
Vauquelinite was first discovered in the pit "Tsvetnoi" on the mountain Uspenskaya in gold - deposit Beryozovsky ( Berezovsk , Berezovsky ), Sverdlovsk Oblast in the Russian Ural Mountains . The mineral was first described in 1818 by Jöns Jakob Berzelius , who named it after the French chemist and discoverer of the element chromium Louis-Nicolas Vauquelin .
classification
In the outdated, but partly still in use, 8th edition of the mineral classification according to Strunz , vauquelinite belonged to the mineral class of "sulfates, chromates, molybdates, wolframates" (as well as some selenates and tellurates) and there to the department of "chromates", where it is part of Phoenicochroit the "Phoenicochroit vauquelinite group" with the system no. VI / F.02 and the other members deaesmithite , edoylerite , fornacite , molybdofornacite , santanaite and wattersite .
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 vauquelinite in the “chromates” department. However, this is further subdivided according to the possible presence and type of additional anions, so that the mineral can be found according to its composition in the subsection "With PO 4 , AsO 4 , SiO 4 ", where it is the only member of the unnamed group 7. FC.05 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking area , assigns vauquelinite to the class of "phosphates, arsenates and vanadates" and there to the department of " phosphates ". Here he is the namesake in the " Vauquelinit group " with the system no. 43.04.03 and the other members Fornacit and Molybdofornacit can be found in the subsection “ Compound phosphates etc., (anhydrous compound anions with hydroxyl or halogen)”.
Crystal structure
Vauquelinite crystallizes monoclinically in the space group P 2 1 / n (space group no. 14, position 2) with the lattice parameters a = 13.75 Å ; b = 5.81 Å; c = 9.56 Å and β = 94.6 ° as well as four formula units per unit cell .
properties
The mineral is easily soluble in nitric acid (HNO 3 ).
Education and Locations
Vauquelinite formed in the oxidation zone of hydrothermal ore - deposits . As accompanying minerals may include Beudantit , Cerussite , Duftit , Krokoit , Mimetite and Pyromorphite occur.
As a rare mineral formation, vauquelinite could only be detected in a few localities, whereby so far (as of 2014) around 70 localities are known. In addition to its “Tsvetnoi” mine type locality , the mineral was also found in Russia in the nearby crocite mine on Uspenskaya Mountain and in various pits in the Berjosowski gold deposit in Sverdlovsk Oblast and on Sukhovyaz near Verkhny Ufalei in Chelyabinsk Oblast .
In Germany, Vauquelinit was found in the Clara mine near Oberwolfach and near Sehringen (Badenweiler Revier) in Baden-Württemberg, at several sites in the area around Reichenbach (Lautertal) in the Hessian Odenwald, in the "Grünbleiberg" mine near Niedergelpe in North Rhine-Westphalia as well as in the Callenberg opencast mine and the “Ludwig-Vereinigt Feld” mine near Schönbrunn in Saxony.
The only known site in Austria so far is the iron deposit near Grassendorf in the Carinthian municipality of Liebenfels (Sankt Veit an der Glan district).
Other locations include Australia, Brazil, the Democratic Republic of the Congo (Zaire), France, Greece, Japan, Kazakhstan, Macedonia, Namibia, South Africa, Hungary, the United Kingdom (UK) and the United States of America (USA ).
See also
literature
- J. Berzelius : Undersökning af ett hittills obemärkt Fossil, som stundom följer den Siberiska kromsyrade blyoxiden . In: Afhandlingar i Fysik, Kemi och Mineralogi . tape 6 , 1818, p. 246–254 (Swedish, rruff.info [PDF; 451 kB ; accessed on March 8, 2018]).
- L. Fanfani, PF Zanazzi: The crystal structure of vauquelinite and the relationships to fornacite . In: Journal of Crystallography . tape 126 , 1968, pp. 433-443 ( rruff.info [PDF; 498 kB ]).
- 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. 684 .
Web links
- Mineral Atlas: Vauquelinite (Wiki)
- Web mineral - Vauquelinite
- Database-of-Raman-spectroscopy - Vauquelinite
- American-Mineralogist-Crystal-Structure-Database - Vauquelinite
Individual evidence
- ^ Friedrich Klockmann : Klockmanns textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp. 618 (first edition: 1891).
- ↑ a b c Stefan Weiss: The large Lapis mineral directory. All minerals from A - Z and their properties . 6th completely revised and supplemented edition. Weise, Munich 2014, ISBN 978-3-921656-80-8 .
- ^ 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. 417 .
- ↑ a b Vauquelinite . 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 kB ; accessed on March 8, 2018]).
- ↑ a b c d e Mindat - Vauquelinite
- ^ Vauquelinite . In: Natural History of New York . Part 3. D. Appleton & Company and Wiley & Putnam, 1842, p. 418 ( limited preview in Google Book search).
- ↑ Mindat - Number of localities for vauquelinite
- ↑ Find location list for vauquelinite at the Mineralienatlas and at Mindat