Skaergaardit

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Skaergaardit
General and classification
other names

IMA 2003-049

chemical formula PdCu
Mineral class
(and possibly department) 		elements
System no. to Strunz
and to Dana 		1.AG.45 ( 8th edition : I / A.14)
02/01/13/01
Crystallographic Data
Crystal system cubic
Crystal class ; symbol cubic hexakisoctahedral; 4 / m  3  2 / m
Space group Pm 3 m (No. 221)Template: room group / 221
Lattice parameters a  = 3.0014 (2)  Å
Formula units Z  = 1
Physical Properties
Mohs hardness 4.5 (VHN 25 = 257)
Density (g / cm 3 ) calculated: 10.64
Cleavage is missing
colour steel gray with a bronze-colored stitch
Line color black
transparency opaque (opaque)
shine Metallic luster

Skaergaardit is a very rarely occurring mineral from the mineral class of the "elements (including natural alloys, intermetallic compounds, carbides, nitrides, phosphides and silicides)" with the chemical composition PdCu and is therefore chemically a natural alloy of palladium and copper in a ratio of 1: 1.

Skaergaardite crystallizes in the cubic crystal system , but has so far only been found in the form of tiny droplets or isometric, rounded grains from 2 to 75 mm in size. The mineral is opaque in every form and shows a clearly metallic sheen on the surfaces of the steel-gray crystals .

Etymology and history

Skaergaardite was first discovered in the intrusion of the same name in the Kangerlussuaq complex in Qeqqata Kommunia in Greenland . The first description followed in 2004 by NS Rudashevsky, AM McDonald, LJ Cabri, TFD Nielsen, CJ Stanley, Yu. L. Kretzer and VN Rudashevsky, who named the mineral after its type locality .

classification

Already in the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the skaergaardite belonged to the mineral class of the "elements" and there to the department of "metals and intermetallic alloys (without semimetals)", where it together with damiaoite , hongshiite , iridium , Palladium , platinum , rhodium and Yixunit the "platinum series" with the system no. I / A.14 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 Skaergaardi to the department of "Metals and Intermetallic Compounds". However, this is further subdivided according to the predominant metals in the compound, which have been divided into metal families according to their related properties. Hongshiit can be found here according to its composition in the sub-section "PGE metal alloys", where it only forms the unnamed group 1.AG.45 together with Hongshiitt .

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the Skaergaardite to the class and there in the department of the same name of "elements". Here he is the only member of the " cesium chloride structure (space group Pm 3 m) " with system no. 02/01/13 within the sub-section "Elements: Platinum Group Metals and Alloys".

Chemism

The theoretical composition of PdCu consists of 62.61% palladium and 37.39% copper. However, the analysis of a total of 311 samples with the aid of the electron microprobe revealed various foreign additions such as 1.12% platinum (Pt), 2.23% gold , 3.85% iron , 1.46% zinc , 1.08% tin , 0.28 % Tellurium and 0.39% lead .

Crystal structure

Skaergaardite crystallizes cubically in the space group Pm 3 m (space group no. 221) with the lattice parameter a  = 3.0014 (2)  Å and one formula unit per unit cell . Template: room group / 221

Education and Locations

At its type locality in the Skaergaard intrusion is Skaergaardit found in tholeiitischem gabbro , where he in paragenesis with plagioclase , clinopyroxene , orthopyroxene , ilmenite , titaniferous magnetite , fayalite and as accessory minerals with various chlorites , Ferrosaponite , hornblende , actinolite , epidote , calcite , Ankerit , Apatite and baddeleyite .

Apart from its type locality and the nearby Platinova Reef in Greenland, Skaergaardite has so far only been able to be found in the Marathon deposit in the Coldwell Complex and at the so-called Anaconda site in the Seeley Lake area near Thunder Bay in the Canadian province of Ontario, in the Kirakkajuppura polymetallic deposit in the Finnish region of Lapland , in the vicinity of Korydallos on the Pindos in the Greek region of Epirus as well as in the Kondjor massif of the Aldan highlands in the Far East and in the Fedorovo-Pansky massif in the Murmansk Oblast of Russia.

See also

literature

  • NS Rudashevsky, AM McDonald, LJ Cabri, TFD Nielsen, CJ Stanley, Yu. L. Kretzer, VN Rudashevsky: Skaergaardite, PdCu, a new platinum-group intermetallic mineral from the Skaergaard intrusion, Greenland . In: Mineralogical Magazine . tape 68 , no. 4 , August 1, 2004, p. 615-632 , doi : 10.1180 / 0026461046840208 .
  • Swapan Kumar Haldar: Platinum-Nickel-Chromium Deposits: Geology, Exploration and Reserve Base . Elsevier, Amsterdam a. a. 2017, ISBN 978-0-12-802041-8 , pp. 11 ( limited preview in Google Book search).
  • Jason Harvey, James MD Day: Highly Siderophile and Strongly Chalcophile Elements in High-Temperature Geochemistry and Cosmochemistry . In: Reviews in Mineralogy and Geochemistry . tape 81 . de Gruyter, 2016, ISBN 978-0-939950-97-3 , ISSN  1529-6466 , p. 513 ( limited preview in Google Book Search - The Platinova Reef, Skaergaard Intrusion).

Web links

Individual evidence

  1. ↑ a b c d e f g h i NS Rudashevsky, AM McDonald, LJ Cabri, TFD Nielsen, CJ Stanley, Yu. L. Kretzer, VN Rudashevsky: Skaergaardite, PdCu, a new platinum-group intermetallic mineral from the Skaergaard intrusion, Greenland . In: Mineralogical Magazine . tape 68 , no. 4 , August 1, 2004, p. 615-632 , doi : 10.1180 / 0026461046840208 .
  2. ↑ Stefan Weiß: The large Lapis mineral directory. All minerals from A - Z and their properties . 6th completely revised and supplemented edition. Weise, Munich 2014, ISBN 978-3-921656-80-8 .
  3. ↑ Find location list for Skaergaardite at the Mineralienatlas and at Mindat