Vincentite

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Vincentite
General and classification
other names

1973-051

chemical formula
  • Pd 3 As
  • (Pd, Pt) 3 (As, Sb, Te)
Mineral class
(and possibly department) 		Sulfides and sulfosalts
System no. to Strunz
and to Dana 		2.AC.05a ( 8th edition : II / A.05)
02.02.05.01
Crystallographic Data
Crystal system monoclinic
Crystal class ; symbol monoclinic prismatic; 2 / m
Space group P 2 / m (No. 10)Template: room group / 10
Lattice parameters a  = 11.226 (3)  Å ; b  = 6.318 (2) Å; c  = 8.047 (2) Å
β  = 100.95 (4) °
Formula units Z  = 8
Physical Properties
Mohs hardness VHN 15 = 494
Density (g / cm 3 ) not measurable; calculated: 10.86
Cleavage not defined
colour light brownish gray
Line color not defined
transparency opaque
shine Metallic luster

Vincentite is a very rarely occurring mineral from the mineral class of "sulfides and sulfosalts" with the idealized chemical composition Pd 3 As and is therefore, from a chemical point of view, an alloy-like compound of palladium and arsenic , which is related to the sulfides .

Based on the empirical analyzes, in which low levels of platinum , antimony and tellurium were also detected, the chemical composition is generally also described in the formula (Pd, Pt) 3 (As, Sb, Te). The elements 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.

Vincentite crystallizes in the monoclinic crystal system , but has so far only been found in the form of microcrystalline grains up to about 40 μm. In the reflected light microscope, the opaque mineral shows a light brownish-gray color and a metallic sheen .

Etymology and history

Vincentite was first discovered near the Riam Kanan River in the Kalimantan Selatan province on the Indonesian island of Borneo . Eugen Friedrich Stumpfl and Mahmud Tarkian published the first description of the mineral in 1974 in the “Mineralogical Magazine” of the Mineralogical Society of Great Britain and Ireland . They named it in honor of Ewart Albert "David" Vincent (1919–2012), the former head of the geological faculty at the University of Manchester (UK).

Holotype material of the mineral is kept in the collection of the Mineralogical Museum of the University of Hamburg .

classification

Already in the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , Vincentite belonged to the mineral class of "sulfides and sulfosalts" and there to the department of "alloys and alloy-like compounds", where together with arsenopalladinite , athenite , genenkinite , isomertieite , Mertieit-I , Mertieit-II , Miessiit ( IMA 2006-013 ), Majakit , Menshikovit , Naldrettit , Palladoarsenid , Palladobismutoarsenid , Palladodymit , Polkanovit , Rhodarsenid , stibiopalladinite , Stillwaterit and Ungavait the "Arsenopalladinit group" with the system number. II / A.05 .

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 Vincentite in the category of "alloys and alloy-like compounds". This is, however, 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 "Alloys of semi-metals with platinum group elements (PGE)", where it is only unnamed together with Athenaite Group 2.AC.05a forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns vincentite 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 02.02.05 within the subsection “Sulphides - including selenides and tellurides - with the composition A m B n X p , with (m + n): p = 3: 1”.

Crystal structure

Vincentite crystallizes monoclinically in the space group P 2 / m (space group no. 10) with the lattice parameters a  = 11.226 (3)  Å ; b  = 6.318 (2) Å; c  = 8.047 (2) Å and β = 100.95 (4) ° and 8 formula units per unit cell . Template: room group / 10

Education and Locations

Vincentite was found in the form of inclusions in iron-containing palladium grains of platinum- gold concentrates which, in addition to the metals mentioned, also contained iridium , osmium and ruthenium .

As a very rare mineral formation, Vincentite is only known from a few samples at around 15 known sites (as of 2016). Its type locality , the Riam Kanan River on Borneo, is the only known site in Indonesia to date.

Other previously known sites are the "Marathon" deposit in the Coldwell Complex in the Thunder Bay District of the Canadian province of Ontario, the V-Ti-Fe deposit "Hongge" near Yanbian in the southwest Chinese province of Sichuan, the Miessijoki river in the municipality of Inari in the Finnish region of Lapland, Lubin in the Polish Voivodeship of Lower Silesia, the Cu-Ni deposit "Talnakh" near Norilsk in eastern Siberia and some sites on the Kola peninsula and in Karelia in Russia, the Sandsloot mine near Mokopane in the South African province of Limpopo, the Sonju Lake Intrusion in the Beaver Bay Complex in Minnesota and the townships of West Nottingham, Chester County and Fulton, Lancaster County , Pennsylvania.

See also

literature

  • Eugen F. Stumpfl, Mahmud Tarkian: Vincentite, a new palladium mineral from south-east Borneo . In: Mineralogical Magazine . tape 39 , 1974, p. 525-527 ( minersoc.org [PDF; 908 kB ]).
  • Mahmud Tarkian, Karl-Heinz Klaska, Eugen F. Stumpfl: New data on vincentite . In: The Canadian Mineralogist . tape 40 , 2002, p. 457-461 ( psu.edu [PDF; 543 kB ]).

Web links

Individual evidence

  1. ↑ a b IMA / CNMNC List of Mineral Names; September 2016 (PDF 1.6 MB; p. 193)
  2. ^ A b 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.  59 .
  3. ↑ a b c d Mahmud Tarkian, Karl-Heinz Klaska, Eugen F. Stumpfl: New data on vincentite . In: The Canadian Mineralogist . tape 40 , 2002, p. 457-461 ( psu.edu [PDF; 543 kB ]).
  4. ↑ Vincentite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 126.6 kB )
  5. ^ Mindat - Vincentite
  6. ↑ Type material catalog of the Mineralogical Museum of the University of Hamburg - Vincentit
  7. ↑ Mindat - Number of localities for Vincentite
  8. ↑ Find location list for Vincentite in the Mineralienatlas and in Mindat