Mrázekit
| Mrázekit | |
|---|---|
 |
|
| General and classification | |
| other names |
IMA 1990-045 |
| chemical formula | Bi 2 Cu 3 [O | OH | PO 4 ] 2 · 2H 2 O |
|
Mineral class (and possibly department) |
Phosphates, arsenates and vanadates |
|
System no. to Strunz and to Dana |
8.DJ.40 ( 8th edition : VII / D.53) 42.04.15.01 |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic primatic; 2 / m |
| Room group (no.) | P 2 1 / n (No. 14) |
| Lattice parameters |
a = 9.06 Å ; b = 6.34 Å; c = 21.24 Å β = 101.6 ° |
| Formula units | Z = 4 |
| Physical Properties | |
| Mohs hardness | 2 to 3 |
| Density (g / cm 3 ) | measured: 4.90 (2); calculated: 5.00 |
| Cleavage | clear to good after {20 1 } |
| colour | sky blue |
| Line color | Light Blue |
| transparency | transparent to translucent |
| shine | Glass gloss |
| Crystal optics | |
| Refractive indices |
n α = 1,800 n β = 1,860 to 1,870 n γ = 1,900 |
| Birefringence | δ = 0.100 |
| Optical character | biaxial negative |
| Axis angle | 2V = measured: 66 ° to 68 ° |
Mrázekite 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 Bi 2 Cu 3 [O | OH | PO 4 ] 2 · 2H 2 O, that is a water-containing bismuth - Copper - phosphate with additional oxygen - and hydroxide ions .
Mrázekit is transparent to translucent and develops needle-like to thin-tabular crystals , but also rosette-shaped, radial or spherical mineral aggregates of sky blue color with light blue streak color . The surfaces of the crystals have a glass-like sheen .
With a Mohs hardness of 2 to 3, Mrázekite is one of the soft to medium-hard minerals that, like the reference minerals gypsum (2) or calcite (3), can either be scratched with a fingernail or with a copper coin.
Special properties
Mrázekit is sensitive to immersion liquids .
Etymology and history
The mineral was first discovered by the mineralogist and collector Zdeněk Mrázek (1952–1984) in the Podlipa deposit near the municipality of Ľubietová on the edge of the Slovak Ore Mountains. Mrázekit was described in 1992 by Tomáš Řídkošil (* 1953), V. Šrein, J. Fábry, Jiří Hybler and BA Maximov, who named the mineral after its discoverer.
The type mineral of the mineral is stored in the Charles University in Prague and the Prague National Museum in the Czech Republic (catalog no. P1N88529).
classification
Already in the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the mrázekite belonged to the mineral class of "phosphates, arsenates and vanadates" and there to the department of "water-containing phosphates with foreign anions ", where together with agardite (Ce ) , Agardite (Dy) , agardite (La) , agardite (Nd) , agardite (Y) , calciopetersite , goudeyite , juanitaite , mixite , parsnite (Ce) , parsnite (Nd) , parsley (Y ) , Plumboagardit and Zálesíit the "Mixit group" with the system no. VII / D.53 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 assigns the Mrázekit to the category of “phosphates etc. with additional anions; with 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 is classified according to its composition in the subsection “With large and medium-sized Cations; (OH etc.): RO 4 = 1: 1 “can be found where it is the only member of the unnamed group 8.DJ.40 .
Also the systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the mrázekite to the class of "phosphates, arsenates and vanadates" and there to the department of "water-containing phosphates etc., with hydroxyl or halogen". Here he is the only member of the unnamed group 04/04/15 within the subdivision “Water-containing phosphates etc., with hydroxyl or halogen with (AB) 5 (XO 4 ) 2 Z q × x (H 2 O)”.
Education and Locations
Mrázekite forms secondary as an oxidation product from polymetallic sulfides. As accompanying minerals may include Beudantit , Bismutit , chalcopyrite , chalcocite , chrysocolla , Libethenit , malachite , Mixit , Pseudomalachit , Pyromorphite , Reichenbachit and tetrahedrite occur.
As a rare mineral formation, Mrázekite could only be proven at a few sites, whereby so far (as of 2014) a little more than 10 sites are known. Its type locality Podlipa near Ľubietová is the only known site in Slovakia to date .
In Germany, Mrázekit was found on a mountain path near Gadernheim and at two sites on the Hohenstein near Lautertal- Reichenbach in the Hessian Odenwald and in the "Arme Hilfe" pit near Ullersreuth in the Saale-Orla district in Thuringia.
Other previously known sites are the wombat cave prospection at Morass Creek Gorge near Benambra in the Australian state of Victoria , a bismuth vein at Brézouard near Sainte-Marie-aux-Mines in France, the "Assunção Mine" near Aldeia Nova (municipality of Ferreira de Aves , Viseu ) in Portugal, Moldova Nouă (German Neumoldowa , Caraș-Severin district) in Romania and Jáchymov in the Czech region of Bohemia.
Crystal structure
Mrázekite crystallizes monoclinically in the space group P 2 1 / n (space group no. 14) with the lattice parameters a = 9.06 Å ; b = 6.34 Å; c = 21.24 Å and β = 101.6 ° as well as four formula units per unit cell .
See also
literature
- Tomáš Řídkošil, V. Šrein, J. Fábry, Jiří Hybler and BA Maximov: Mrázekite, Bi 2 Cu 3 (OH) 2 O 2 (PO 4 ) 2 · 2H 2 O, a new mineral species and its crystal structure. In: Canadian Mineralogist. Volume 30, 1992, pp. 215-224.
- H. Effenberger, W. Krause, K. Belendorf, HJ. Berhardt, O. Medenbach, Jiří Hybler, V. Petříček: Revision of the crystal structure of mrázekite, Bi 2 Cu 3 (OH) 2 O 2 (PO 4 ) 2 · 2H 2 O. In: Canadian Mineralogist. Volume 32, 1994, pp. 365-372.
Web links
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. 495 .
- ↑ Webmineral - Mrázekite
- ↑ a b c d Mrázekite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 68.2 kB )
- ↑ a b c Mindat - Mrázekite
- ↑ Mineral Atlas: Mrázekit
- ↑ Mindat - Number of localities for Mrázekit
- ↑ Find location list for Mrázekite at the Mineralienatlas and at Mindat