Fingerit
| Fingerit | |
|---|---|
| General and classification | |
| other names |
IMA 1983-064 |
| chemical formula | Cu 11 [O 2 | (VO 4 ) 6 ] |
|
Mineral class (and possibly department) |
Phosphates, arsenates and vanadates |
|
System no. to Strunz and to Dana |
8.BB.80 ( 8th edition : VII / B.07) 11.11.03.01 |
| Crystallographic Data | |
| Crystal system | triclinic |
| Crystal class ; symbol | triclinic pinacoidal; 1 |
| Space group | P 1 (No. 2) |
| Lattice parameters |
a = 8.16 Å ; b = 8.27 Å; c = 8.04 Å, α = 107.1 °; β = 91.4 °; γ = 106.4 ° |
| Formula units | Z = 1 |
| Twinning | Contact and multiple twins with the axis of rotation [010] |
| Physical Properties | |
| Mohs hardness | not defined |
| Density (g / cm 3 ) | calculated: 4.776 |
| Cleavage | not defined |
| Break ; Tenacity | not defined |
| colour | black, also medium gray in incident light |
| Line color | dark reddish brown |
| transparency | opaque |
| shine | Metallic luster |
Fingerite is an extremely rare mineral from the mineral class of " phosphates , arsenates and vanadates ". It crystallizes in the triclinic crystal system with the chemical composition Cu 11 [O 2 | (VO 4 ) 6 ], so from a chemical point of view it is a copper vanadate.
So far, fingerite could only be found in the form of microcrystalline aggregates with hypidiomorphic , isometric crystals of black color with dark reddish-brown streak color . The mineral is opaque and has a metallic sheen .
Etymology and history
Fingerite was first discovered on the Izalco volcano in the Santa Ana department in El Salvador and described in 1985 by JM Hughes and CG Hadidiacos, who named the mineral after Larry W. Finger (* 1940) from the geophysical laber of the Carnegie Institution for Science in Washington, who named the Analyzed crystal structure of the mineral.
The type material of the mineral has been deposited in the National Museum of Natural History and the Carnegie Institution for Science in Washington.
classification
In the now outdated, but still in use 8th edition of the mineral classification according to Strunz , the fingerite belonged to the division of "anhydrous phosphates, with foreign anions F, Cl, O, OH", where it was unnamed along with Averievit , Coparsit , Stoiberit and Urusovit Group VII / B.07 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 fingerite 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 to the phosphate, arsenate or vanadate complex (RO 4 ), so that the mineral can be classified in the sub-section “With only medium-sized cations; (OH etc.): RO 4 ≤ 1: 1 “can be found where it is the only member of the unnamed group 8.BB.80 .
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns fingerite 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 11/41/03 within the sub-section “Anhydrous phosphates etc., with hydroxyl or halogen with different formulas”.
Crystal structure
Fingerite crystallizes triclinic in the space group P 1 (space group no. 2) with the lattice parameters a = 8.16 Å ; b = 8.27 Å; c = 8.04 Å; α = 107.1 °; β = 91.4 ° and γ = 106.4 ° and one formula unit per unit cell .
Education and Locations
Fingerite is deposited at about 100 to 200 ° C from vanadium-containing sublimates in fumaroles on basaltic volcanic craters . Bannermanite , chalcanthite , chalcocyanite , euchlorine , shcherbinaite , stoiberite , thénardite and ziesite appear as accompanying minerals .
So far (as of 2013) the mineral could only be found at its type locality on the Izalco volcano in El Salvador.
See also
literature
- John M. Hughes, CG Hadidiacos: Fingerite, Cu 11 O 2 (VO 4 ) 6 , a new vanadium sublimate from lzalco volcano, El Salvador: descriptive minerology , In: American Mineralogist , Volume 70 (1985), pp. 193-196 ( PDF; 416.9 kB )
- Larry W. Finger: Fingerite, Cu 11 O 2 (VO 4 ) 6 , a new vanadium sublimate from Izalco volcano, El Salvador: crystal structure , In: American Mineralogist , Volume 70 (1985), pp. 197-199 ( PDF; 337.3 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. 444 .
- ↑ Webmineral - Fingerite
- ↑ a b c Fingerite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF; 64.2 kB )
- ↑ Mindat - Fingerite