Wicksit
| Wicksit | |
|---|---|
| General and classification | |
| other names |
IMA 1979-019 |
| chemical formula | NaCa 2 (Fe 2+ , Fe 3+ , Mn 2+ , Mg) 6 [PO 4 ] 6 · 2H 2 O |
|
Mineral class (and possibly department) |
Phosphates, arsenates and vanadates |
|
System no. to Strunz and to Dana |
8.CF.05 ( 8th edition : VII / C.18) 02/40/10/01 |
| Crystallographic Data | |
| Crystal system | orthorhombic |
| Crystal class ; symbol | orthorhombic-dipyramidal; 2 / m 2 / m 2 / m |
| Room group (no.) | Pcab (No. 61) |
| Lattice parameters | a = 12.52 Å ; b = 12.91 Å; c = 11.65 Å |
| Formula units | Z = 4 |
| Frequent crystal faces | {010} |
| Physical Properties | |
| Mohs hardness | 4.5 to 5 |
| Density (g / cm 3 ) | measured: 3.54 (2); calculated: 3.58 |
| Cleavage | good after {010} |
| colour | dark blue, dark green to almost black |
| Line color | green |
| transparency | opaque, translucent in thin layers |
| shine | Semi-metallic luster |
| Crystal optics | |
| Refractive indices |
n α = 1.713 (3) n β = 1.718 (3) n γ = 1.728 (3) |
| Birefringence | δ = 0.015 |
| Optical character | biaxial positive |
| Axis angle | 2V = 66 ° (measured); 72 ° (calculated) |
| Pleochroism | strong: X = blue; Y = greenish blue; Z = light yellowish brown |
Wicksite is a very rarely occurring mineral from the mineral class of " phosphates , arsenates and vanadates ". It crystallizes in the orthorhombic crystal system with the formula NaCa 2 (Fe 2+ , Fe 3+ , Mn 2+ , Mg) 6 [PO 4 ] 6 · 2 H 2 O, so from a chemical point of view it is a water-containing and complexly composed sodium - calcium - Phosphate. The additional elements iron , manganese and magnesium indicated in the round brackets can represent each other in the formula ( substitution , diadochie), but are always in the same proportion to the other components of the mineral.
Wicksit is generally opaque and only translucent in thin layers. It rarely develops tabular and striped crystals , which can then be up to one centimeter in size. It is mostly found in the form of granular to massive mineral aggregates . Its color varies from dark blue and dark green to almost black. However, Wicksit leaves a clearly green line on the marking board .
Etymology and history
Wicksite was first discovered on the Big Fish River near Dawson in the Yukon Territory of Canada and described in 1981 by Bozidar Darko Sturman , Donald R. Peacor and Pete J. Dunn , who named the mineral after Frederick John Wicks , the curator of the Royal's mineralogical collection Ontario Museum .
The type material of the mineral has been found in the collection of the Royal Ontario Museum (Register No. M373U ) and some fragments of the mineral in the Smithsonian Institution (Register No. NMNH 145607 ) and in the National Mineral Collection of the Geological Survey of Canada (Register No. 61309 ).
classification
In the meantime outdated, but still in use 8th edition of the mineral classification by Strunz of Wicksit belonged to the mineral class of "phosphates, arsenates and vanadates" and then to the Department of "water containing phosphates without foreign anions " where he along with bederite , Grischunit and Walentait formed the unnamed group VII / C.18 .
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 wicksite to the class of “phosphates, arsenates and vanadates” and there to the department of “phosphates etc. without additional anions ; with H 2 O “. However, this section is further subdivided according to the relative size of the cations involved and the molar ratio of phosphate, arsenate or vanadate complex (RO 4 ) to the water of crystallization contained , so that the mineral is classified in the sub-section “With large and medium-sized cations; RO 4 : H 2 O> 1: 1 "is to be found where it is named after the" Wicksit Group "with the system no. 8.CF.05 and the other members Bederit, Grischunit and Tassieit .
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the wicksite to the class of "phosphates, arsenates and vanadates" and there in the department of "water-containing phosphates etc.". Here he can be found together with Bederit and Tassieit in the unnamed group 02/40/10 within the subdivision of " Water-containing phosphates etc., with A 2+ (B 2+ ) 2 (XO 4 ) × x (H 2 O) ".
Education and Locations
Wicksite forms in nests embedded in slate and ironstone formations. As Begleitminerale occur among other Ludlamit , Marićit , Satterlyit , pyrite , quartz , Vivianit and Wolfeit .
So far (as of 2012) wicksite could only be detected in a few samples from three localities. In addition to its Big Fish River type locality in the Dawson mining area in Canada, these are Hålsjöberg near Torsby (Värmland) in Sweden and the “Bull Moose Mine” near Custer (South Dakota) in the USA.
Crystal structure
Wicksite crystallizes orthorhombically in the space group Pcab (space group no. 61) with the lattice parameters a = 12.52 Å ; b = 12.91 Å and c = 11.65 Å and 4 formula units per unit cell .
See also
literature
- B. Darko Sturman, Donald R. Peacor, Pete J. Dunn: Wicksite, a new mineral from Northeastern Yukon Territory , in: Canadiun Mineralogist , Volume 19 (1981), pp. 377-380 ( PDF 295.3 kB )
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. 482 .
- ↑ Webmineral - Wick Site
- ↑ a b c d e John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols: Wicksite , in: Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 65.2 kB )
- ↑ a b c d e Mindat - Wicksite