Orcelite

from Wikipedia, the free encyclopedia
Orcelite
General and classification
chemical formula Ni 5-x As 2 (x = 0.23)
Mineral class
(and possibly department) 		Sulfides and sulfosalts
System no. to Strunz
and to Dana 		2.AB.10 ( 8th edition : II / A.04)
02.03.02.01
Crystallographic Data
Crystal system hexagonal
Crystal class ; symbol dihexagonal-pyramidal 6 mm
Room group (no.) P 6 3 cm (No. 185)
Lattice parameters a  = 6.70  Å ; c  = 12.39 Å
Formula units Z  = 6
Physical Properties
Mohs hardness not defined
Density (g / cm 3 ) measured: 6.5; calculated: 8.50
Cleavage Please complete!
colour yellow-white, pink to bronze-colored (more brown than nickel)
Line color Please complete!
transparency opaque
shine Metallic luster

Orcelite is a rarely occurring mineral from the mineral class of " sulfides and sulfosalts ". It crystallizes in the hexagonal crystal system with the chemical composition Ni 5-x As 2 (x = 0.23) and has so far only been found in the form of scattered grains enclosed in pentlandite . The color of the opaque crystallites can be yellow-white or pink to bronze-colored and is similar to nickel , but is more brown than this.


Etymology and history

Orcelite was first discovered in the Tiébaghi ​​massif near the municipality of Koumac in the northern province of New Caledonia and described in 1959 by S. Caillère, J. Avias and J. Falgueirettes, who named the mineral after the French physicist, chemist and mineralogist Jean Orcel (1896–1978 ) named.

classification

In the now outdated, but still common 8th edition of the mineral classification according to Strunz , orcelite belonged to the mineral class of "sulfides and sulfosalts" and there to the department of "alloys and alloy-like compounds", where it formed an independent group together with Maucherite .

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 orcelite to the class of "sulfides and sulfosalts" and there to the department of "alloys and alloy-like compounds". However, this division 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-division "Nickel-Semi-Metal Alloys", where it is the only member of the unnamed group 2.AB.10 .

The systematics of minerals according to Dana also assigns orcelite to the class of "sulfides and sulfosalts" and there into the category of "sulfide minerals". Here he is the only member of the unnamed group 02.03.01 within the subdivision of " Sulphides - including selenides and tellurides - with the composition A m B n X p , with (m + n): p = 5: 2 ".

Education and Locations

Orcelit formed in serpentinierten Harzburgiten usually in Paragenesis with Balenit , Breithauptit , chalcopyrite , chalcocite , Heazlewoodite , magnetite , Maucherite , millerite , parkerite , pentlandite and solid nickel and copper .

In total, orcelite has so far (as of 2011) been found at 14 sites. The only known site in Germany is the Heimberg quarry near Wolfshagen in the Harz Mountains in Lower Saxony. Orcelite was also found near Zeehan on Tasmania in Australia; Goze Deltschew in the Bulgarian Oblast Blagoevgrad; at Vourinos in the Greek regional district of Kozani ; in the Baula complex in the Indian state of Orissa ; in Val Malenco in the Italian province of Sondrio ; Karabash in Russia; near Mijas and in the Sierra Alpujata ( province of Málaga ) in Spain; at Brunflo in Sweden and at Eskişehir in Turkey.

Crystal structure

Orcelite crystallizes hexagonally in the space group P 6 3 cm (space group no. 185) with the lattice parameters a  = 6.70  Å and c  = 12.39 Å; as well as 6 formula units per unit cell .

See also

Individual evidence

  1. ↑ 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. 59 .
  2. ↑ Webmineral - Orcelite (English)
  3. ↑ a b Handbook of Mineralogy - Orcelite (English, PDF 62.9 kB)
  4. ↑ Mindat - Orcelite (English)

literature

Web links