Iridarsenite
| Iridarsenite | |
|---|---|
| General and classification | |
| other names |
IMA 1973-021 |
| chemical formula | (Ir, Ru) As 2 |
|
Mineral class (and possibly department) |
Sulfides and sulfosalts |
|
System no. to Strunz and to Dana |
2.AC.50 ( 8th edition : II / D.20) 02.12.04.05 |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | 2 / m |
| Space group | P 2 1 / c |
| Lattice parameters |
a = 6.05 Å ; b = 6.06 Å; c = 6.18 Å β = 113 ° 17 ' Please complete the source as an individual reference |
| Formula units | Z = 4 Please complete the source as an individual reference |
| Physical Properties | |
| Mohs hardness | 5 to 5.5 |
| Density (g / cm 3 ) | 10.9 |
| Cleavage | Please complete |
| colour | gray with a brownish tinge |
| Line color | Please complete |
| transparency | opaque |
| shine | metallic |
Iridarsenite is a very rare mineral from the mineral class of sulfides and sulfosalts . It crystallizes in the monoclinic crystal system with the chemical composition (Ir, Ru) As 2 and forms irregularly shaped, up to 60 μm inclusions in rutheniridosmin of gray color.
Etymology and history
The mineral was found in 1974 by DC Harris in its type locality , the Waria River in the province of Oro in Papua New Guinea . It is named after its composition of the elements iridium and arsenic .
classification
In the Strunz system , iridarsenite is counted among the sulfides and sulfosalts. After the 8th edition it forms together with anduoite , ferroselite , Frohbergite , kullerudite , marcasite , mattagamite and omeiite the marcasite group, a subgroup of sulphides with a ratio of metal to sulfur, selenium or tellurium of <1: 1. In the 9th edition it forms with Borishanskiit a subgroup of the compounds of semimetals with platinum group elements (PGE), which is one of the alloys and alloy-like compounds.
In the classification by Dana it forms with arsenopyrite , Gudmundit , Osarsit , Ruarsit and Clinosafflorit the arsenopyrite sub-group of the sulfides, selenides and tellurides with Composition A m B n X p , with (m + n): p = 1: 2.
Education and Locations
Iridarsenite forms in nuggets of natural osmium-iridium-ruthenium alloys. It is associated with irarsite , ruthenarsenite and rutheniridosmin.
Only a few locations are known of this very rare mineral. In addition to its type locality, iridarsenite was found in Amdo in the Tibet Autonomous Region ( China ), on Cuba , in the Sajan Mountains in Russia , Witwatersrand in South Africa and Goodnews Bay in the US state of Alaska .
Crystal structure
Iridarsenite crystallizes in the monoclinic crystal system in the space group P 2 1 / c with the lattice parameters a = 6.05 Å ; b = 6.06 Å, c = 6.18 Å and β = 113 ° 17 'as well as four formula units per unit cell .
See also
Individual evidence
literature
- Iridarsenite in: Anthony et al .: Handbook of Mineralogy , 1990, 1, 101 ( pdf ).