Sperrylite
| Sperrylite | |
|---|---|
 |
|
| General and classification | |
| chemical formula | PtAs 2 |
|
Mineral class (and possibly department) |
Sulfides and sulfosalts |
|
System no. to Strunz and to Dana |
2.EB.05a ( 8th edition : II / D.17) 02.12.01.13 |
| Crystallographic Data | |
| Crystal system | cubic |
| Crystal class ; symbol | disdodecahedral; 2 / m 3 |
| Room group (no.) | Pa 3 (No. 205) |
| Lattice parameters | a = 5.97 Å |
| Formula units | Z = 4 |
| Frequent crystal faces | {100}, {111}, {110}, {210} |
| Physical Properties | |
| Mohs hardness | 6 to 7 (VHN 100 = 960 to 1277 ⊥ (100) and (111)) |
| Density (g / cm 3 ) | measured: 10.58; calculated: 10.78 |
| Cleavage | indistinct after {001} |
| Break ; Tenacity | shell-like |
| colour | tin white |
| Line color | black |
| transparency | opaque |
| shine | strong metallic luster |
Sperrylite is a rather seldom occurring mineral from the mineral class of the " sulfides and sulfosalts (including selenides, tellurides, arsenides, antimonides, bismuthides, sulfarsenites, sulfantimonites, sulfbismuthites)". It crystallizes in the cubic crystal system with the chemical composition PtAs 2 , that is a platinum - arsenide or more precisely a Platinbiarsenid .
Sperrylith usually develops complex combinations of cubic crystals , but also occurs in the form of massive mineral aggregates . The mineral is opaque even in thin layers and the surfaces of the tin-white crystals show a strong metallic luster . However, Sperrylith leaves a black line on the marking board .
With a Mohs hardness of 6 to 7, Sperrylite is one of the medium-hard to hard minerals, which means that it can just about be scratched with a steel file, but it can even scratch simple window glass.
Etymology and history
Sperrylite was first discovered in the "Vermilion Mine" near Denison Township in the Sudbury District of the Canadian province of Ontario and was described in 1889 by Horace Lemuel Wells (1855-1924), who named the mineral after its discoverer, the chemist Francis Louis Sperry (1861-1906) , and the Greek word λίθος [lithos] for "stone".
The type material of the mineral is kept in the Royal Ontario Museum in Canada and in Yale University in New Haven (Connecticut, Register No. 1.2950, 1.5895).
classification
In the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the sperrylite belonged to the general section of "sulphides and sulphosalts with the molar ratio of metal: sulfur, selenium, tellurium <1: 1", where together with aurostibite , cattierite , Changchengit , Dzharkenit , Erlichmanit , Fukuchilit , Geversit , Hauerit , Insizwait , Krutaite , Laurit , Maslovit , Mayingit , Michenerit , Padmait , Penroseite , pyrite , Testibiopalladit , Trogtalit , Vaesit and Villamanínit the "pyrite group" with the system number. II / D.17 formed.
The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the IMA, classifies sperrylite under the category of “metal sulphides with a molar ratio of metal: sulfur ≤ 1: 2”. However, this section is further subdivided according to the exact metal-sulfur ratio and the metal ions contained in the formula, so that the mineral is classified according to its composition in the sub-section “M: S = 1: 2, with Fe , Co , Ni , PGE etc. ”is to be found where it is a member of the still existing pyrite group with the system no. 2.EB.05a and the other members Aurostibit, Cattierit, Dzharkenit, Erlichmanit, Fukuchilit, Gaotaiit, Geversit, Hauerit, Insizwait, Iridisit, Kruťait, Laurit, Penroseit, Pyrite, Trogtalit, Vaesit and Villamanínit.
The systematics of minerals according to Dana also assigns sperrylite to the class of "sulfides and sulfosalts" and there in the department of "sulfide minerals", where it is also in the "pyrite group (isometric: Pa3)" with the system no. 02.12.01 within the subsection " Sulphides - including selenides and tellurides - with the composition Am Bn Xp, with (m + n): p = 1: 2 " can be found.
Crystal structure
Sperrylite crystallizes cubically in the space group Pa 3 (space group no. 205) with the lattice parameter a = 5.97 Å and 4 formula units per unit cell .
properties
Sperrylite is very stable towards acids and is not attacked by them.
Education and Locations
Sperrylith is the most widely used platinum mineral and forms as yet verwitterungsbeständigstes Arseniderz in any type of platinum - deposit , but also in intra magmatic chromite storage sites, that is, in chromitführendem ultrabasischem rock . There it occurs in paragenesis with many other minerals such as lead amalgam , bornite , chalcopyrite , cooperite , cubanite , danbaite , galena , gersdorffite , gold , ilmenite , iridosmin , kotulskite , laurite, linneit , magnetite , merenskyite , millerite , niggliite , omeiite , Pentlandite , solid platinum, pyrite , pyrrhotite , sphalerite , stibnite , sudburyite , testibiopalladite , violarite ,
Overall, sperrylite is a rather rare mineral formation, which means that it can sometimes be abundant at different sites, but is otherwise not very common. So far (as of 2013) around 260 sites are known to be known. In addition to its type locality "Vermilion Mine", the mineral appeared in Canada in many other mines in the Sudbury District , Rainy River District , Thunder Bay District and Timiskaming District in Ontario as well as in several pits in British Columbia and Québec . Individual sites are also known in other states of Canada.
In Germany, sperrylith has so far only been found near Wittichen and Todtmoos in Baden-Württemberg, in the heavy mineral soaps of the Danube near Straubing in Bavaria and in the nickel ore deposit on Hornsberg near Äußerstemittelohland in Saxony.
The only known site in Austria so far is Kraubath an der Mur in the Austrian state of Styria, and in Switzerland the mineral is only known from the Turtmann valley .
The Cu-Ni deposit Talnakh near Norilsk on the Taimyr peninsula in eastern Siberia (Russia), in which the best developed and the largest crystals with a diameter of about five centimeters, are found due to the extraordinary sperrylite finds. Crystals up to four centimeters in size were found on the “Tweefontein Farm” near Mokopane (formerly Potgietersrus ) in the eastern Bushveld complex (Limpopo) in South Africa.
Other sites are in Ethiopia, Albania, Argentina, Australia, Botswana, Brazil, Bulgaria, China, Czech Republic, Ecuador, Finland, Greece, Greenland, India, Indonesia, Italy, Japan, Madagascar, Morocco, Mongolia, New Caledonia, New Zealand, Norway, Russia, Sweden, Zimbabwe, Spain, South Africa, Ukraine, the United Kingdom (UK), the United States of America (USA) and Vietnam.
use
As the main carrier of the platinum content (max. 56.56%) of many "nickel magnetic gravel" deposits (intergrowth aggregate of pyrrhotite and pentlandite), Sperrylite is an important platinum ore .
See also
literature
- Horace L. Wells: Sperrylite, a new mineral. In: American Journal of Science. (1889), Volume 137, pp. 67-70 ( PDF 434 kB )
- Friedrich Klockmann : Klockmann's textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke , Stuttgart 1978, ISBN 3-432-82986-8 , pp. 459 (first edition: 1891).
- Helmut Schrätze, Karl-Ludwig Weiner: Mineralogy. A textbook on a systematic basis . de Gruyter, Berlin; New York 1981, ISBN 3-11-006823-0 , pp. 253-254 .
- 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. 320-321 .
Web links
- Mineral Atlas: Sperrylite (Wiki)
- Database-of-Raman-spectroscopy - Sperrylite
- American-Mineralogist-Crystal-Structure-Database - Sperrylite
Individual evidence
- ^ A b c 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. 104 .
- ^ Helmut Schrätze, Karl-Ludwig Weiner: Mineralogie. A textbook on a systematic basis . de Gruyter, Berlin; New York 1981, ISBN 3-11-006823-0 , pp. 253 .
- ↑ a b c d Sperrylite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 62.6 kB )
- ↑ Russel H. Chittenden: Biographical Memoir of Horace Lemuel Wells. In: National Academy of Sciences 1925 ( PDF 762.9 kB )
- ↑ Mindat - Sperrylith (English)
- ↑ 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. 321 .
- ↑ Mindat - Number of localities for sperrylite
- ↑ Petr Korbel, Milan Novák: Mineral Encyclopedia . Nebel Verlag GmbH, Eggolsheim 2002, ISBN 3-89555-076-0 , p. 44 ( Dörfler Natur ).
- ↑ List of localities for sperrylite in the Mineralienatlas and Mindat
- ↑ Webmineral - Strunzite (English)