Westerveldit
| Westerveldit | |
|---|---|
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| General and classification | |
| other names |
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| chemical formula |
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Mineral class (and possibly department) |
Sulfides and sulfosalts |
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System no. to Strunz and to Dana |
2.CC.15 ( 8th edition : II / C.19) 08/02/19/01 |
| Crystallographic Data | |
| Crystal system | orthorhombic |
| Crystal class ; symbol | orthorhombic-dipyramidal; 2 / m 2 / m 2 / m |
| Space group | Pmcn (No. 62, position 5) |
| Lattice parameters | a = 3.46 Å ; b = 5.97 Å; c = 5.33 Å |
| Formula units | Z = 4 |
| Physical Properties | |
| Mohs hardness | 6 to 7 |
| Density (g / cm 3 ) | calculated: 8.13 ( VHN 25 = 707-798) |
| Cleavage | not defined |
| colour | brownish white, gray |
| Line color | not defined |
| transparency | opaque |
| shine | Metallic luster |
Westerveldit is a rarely occurring mineral having the idealized chemical composition FeAs and is thus chemically seen an iron arsenide , more specifically, an iron (III) arsenide with the molar ratio of iron : arsenic 1. Due to the chemical affinity of: = 1 Arsenide with the sulfides heard the Westerveldite to the mineral class of the "sulfides and sulfosalts".
Since some of the iron in naturally formed Westerveldites is usually replaced ( substituted ) by nickel and occasionally also by cobalt , the chemical composition is also given in various sources as a mixed formula with (Fe, Ni) As or (Fe, Ni, Co) As . The elements indicated in round brackets can represent each other in the formula, but are always in the same proportion to the arsenic content of the mineral.
Westerveldite crystallizes in the orthorhombic crystal system , but has so far only been found in maucherite in the form of microcrystalline, enclosed granules between 1 μm and 25 μm in diameter . The mineral is opaque in every form and shows a metallic sheen on the surfaces of the brownish-white to gray granules .
Etymology and history
Westerveldite was first discovered in the La Gallega mine near Ojén in the Spanish province of Málaga . It was first described in 1972 by IS Oen, EAJ Burke, C. Kieft and AB Westerhof, who named the mineral after Jan Westerveld (1905–1962). Between 1945 and 1962 he was professor of geology and mineralogy at the Universiteit van Amsterdam .
Type material of the mineral is stored in the geological institute of the Universiteit van Amsterdam as well as in the institute for geosciences of the Vrije Universiteit Amsterdam in the Netherlands.
classification
In the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the Westerveldite belonged to the mineral class of "sulphides and sulphosalts (including selenides, tellurides, arsenides, antimonides and bismuthides)" and there to the department of "sulphides with the proportion of metal: S, Se, Te ≈ 1: 1 “, where together with Achávalit , Heideit , Jaipurit , Modderit , Pyrrhotin , Smythit and Troilit he formed the unnamed group II / C.19 .
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 Westerveldite in the category of "Metal sulfides, M: S = 1: 1 (and similar)". However, this is further subdivided according to the predominant metals in the compound, so that the mineral can be found according to its composition in the sub-section "with nickel (Ni), iron (Fe), cobalt (Co) etc.", where it is named the "Westervelditgruppe" with the system no. 2.CC.15 and the other members Cherepanovit , Modderit and Ruthenarsenit forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking area , assigns the Westerveldite to the class of "sulfides and sulfosalts" and there in the department of "sulfide minerals". Here he is the only member of the unnamed group 08/02/19 within the subsection “Sulphides - including selenides and tellurides - with the composition A m B n X p , with (m + n): p = 1: 1”.
Crystal structure
Westerveldite crystallizes orthorhombically in the space group Pmcn (space group no. 62, position 5) with the lattice parameters a = 3.46 Å ; b = 5.97 Å and c = 5.33 Å as well as four formula units per unit cell .
Education and Locations
At its type locality , the very high-temperature chromite - Nickel - Ore - deposit La Gallega mine in Spain, located Westerveldit found as tiny inclusions in Maucherite , where he also occurring the Nickelin displaced. The chromite and socialized cordierite - stone by pulling in streaks like veins the serpentinized , ultramafic rocks . In addition to Maucherite and Nickelin, Westerveldite can also occur in paragenesis with native antimony , cobaltite , iron and cobalt-rich Gersdorffite , nickel-containing Löllingite , Rammelsbergite and various serpentines .
In addition to the La Gallega mine near Ojén, the mineral was found in Spain at El Sapo and Los Jarales near Carratraca in the Andalusian province of Málaga and at A Franqueira near A Cañiza in the Galician province of Pontevedra .
Other previously known sites are the Birchtree Mine near Thompson (Manitoba) in Canada, Igdlunguaq in the Tunulliarfik Fjord (Tunugdliarfik) in the Danish municipality of Kujalleq , the Routakallio quarry near Seinäjoki in western Finland, the Vispi quarry on the Pian di Celle volcano in the central Italian municipality San Venanzo , the Chibinen on the Russian Kola Peninsula , the copper-cobalt ore field at Tunaberg near Nyköping in the Swedish province of Södermanland County and Bow in Merrimack County in the US state of New Hampshire.
use
Due to its rarity, Westerveldite is only of interest to the mineral collector.
See also
literature
- IS Oen, EAJ Burke, C. Kieft, AB Westerhof: Westerveldite, (Fe, Ni, Co) As, a new mineral from La Gallega, Spain . In: American Mineralogist . tape 57 , 1972, p. 354-363 ( minsocam.org [PDF; 693 kB ; accessed on May 30, 2018]).
- MB Sizgoric, CM Duesing: Westerveldite, a Canadian occurrence . In: The Canadian Mineralogist . tape 12 , 1973, p. 137–138 ( rruff.info [PDF; 341 kB ; accessed on May 30, 2018]).
- Skage R. Hem, Emil Makovicky, Fernando Gervilla: Compositional trends in Fe, Co, and Ni sulfarsenides and their crystal-chemical implications: results from the Arroyo de la Cueva deposits, Ronda peridotite, southern Spain . In: The Canadian Mineralogist . tape 39 , 2001, p. 831–853 ( rruff.info [PDF; 568 kB ; accessed on May 30, 2018]).
Web links
- Mineral Atlas: Westerveldite (Wiki)
- RRUFF Database-of-Raman-spectroscopy - Westerveldite (English)
- American-Mineralogist-Crystal-Structure-Database - Westerveldite (English)
Individual evidence
- ^ Karl Hugo Strunz , Christel Tennyson : Mineralogical tables . 8th edition. Academic publishing company Geest & Portig KG, Leipzig 1982, p. 122 .
- ↑ a b c d 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. 87 .
- ↑ a b c 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. 331 .
- ↑ a b c d e Westerveldite . 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; 58 kB ; accessed on May 30, 2018]).
- ↑ a b Friedrich Klockmann : Klockmanns textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp. 446 (first edition: 1891).
- ↑ Webmineral - Westerveldite (English)
- ↑ Richard V. Gaines, H. Catherine W. Skinner, Eugene E. Foord, Brian Mason , Abraham Rosenzweig: Dana's New Mineralogy . 8th edition. John Wiley & Sons, New York (et al.) 1997, ISBN 0-471-19310-0 , pp. 82 .
- ↑ Mindat - Westerveldite (English)
- ^ MB Sizgoric, CM Duesing: Westerveldite, a Canadian occurrence . In: The Canadian Mineralogist . tape 12 , 1973, p. 137 ( rruff.info [PDF; 341 kB ; accessed on May 30, 2018]).
- ^ IS Oen, EAJ Burke, C. Kieft, AB Westerhof: Westerveldite, (Fe, Ni, Co) As, a new mineral from La Gallega, Spain . In: American Mineralogist . tape 57 , 1972, p. 354–363 ( rruff.info [PDF; 693 kB ; accessed on May 30, 2018]).
- ↑ Paul Ramdohr : The ore minerals and their adhesions . 4th, revised and expanded edition. Akademie-Verlag, Berlin 1975, p. 673 .
- ↑ Find location list for Westerveldite at the Mineralienatlas and at Mindat