Atheneity
| Atheneity | |
|---|---|
| General and classification | |
| other names |
IMA 1973-050 |
| chemical formula | (Pd, Hg) 3 As |
|
Mineral class (and possibly department) |
Sulfides and sulfosalts |
|
System no. to Strunz and to Dana |
2.AC.05a ( 8th edition : II / A.05) 02.02.04.01 |
| Crystallographic Data | |
| Crystal system | hexagonal |
| Crystal class ; symbol | ditrigonal-dipyramidal; 6 m 2 |
| Space group | P 6 2 m (No. 189) |
| Lattice parameters | a = 6.798 Å ; c = 3.483 Å |
| Formula units | Z = 2 |
| Physical Properties | |
| Mohs hardness | 5 |
| Density (g / cm 3 ) | 10.2 |
| Cleavage | Please complete |
| colour | white with a bluish cast |
| Line color | Please complete |
| transparency | opaque |
| shine | metallic |
Atheneite is a very rare mineral from the mineral class of sulphides and sulphosalts . It crystallizes in the hexagonal crystal system with the chemical composition (Pd, Hg) 3 As and forms small, ingrown bubbles of white color.
Etymology and history
The mineral was discovered in 1974 by AM Clark, AJ Criddle and EE Fejer in the Itabira type locality in the Brazilian state of Minas Gerais . They named the new mineral after the Greek goddess Pallas Athene . The name was chosen because of the contained element palladium .
classification
Already in the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the athenite belonged to the mineral class of "sulfides and sulfosalts" and there to the department of "alloys and alloy-like compounds", where together with arsenopalladinite , genenkinite , isomertieite , mertieite -I , Mertieit-II , Miessiit ( IMA 2006-013 ), Majakit , Menshikovit , Naldrettit , Palladoarsenid , Palladobismutoarsenid , Palladodymit , Polkanovit , Rhodarsenid , stibiopalladinite , Stillwaterit , Ungavait and Vincentit 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 the Atheneit under the category of "Alloys and alloy-like compounds". However, this 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-section "Alloys of semi-metals with platinum group elements (PGE)", where it is only together with Vincentite the unnamed Group 2.AC.05a forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the Atheneit 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 02.02.04 within the subdivision “Sulphides - including selenides and tellurides - with the composition A m B n X p , with (m + n): p = 3: 1”.
Crystal structure
Athenaite crystallizes in the hexagonal crystal system in the space group P 6 2 m (space group no. 189) with the lattice parameters a = 6.798 Å and c = 3.483 Å as well as two formula units per unit cell .
Education and Locations
Athenaite forms in concentrates of gold washings . It is associated with arsenopalladinite , palladite , isomerite and hematite .
Only a few locations are known of the very rare mineral. Besides its type locality, atheneit was found in Curionópolis , in the Brazilian state of Pará , in the Republic of Komi and near Lake Baikal in Russia and in the Bushveld complex in South Africa .
See also
literature
- Atheneit in: Anthony et al .: Handbook of Mineralogy , 1990, 1, 101 ( pdf ).
Web links
Individual evidence
- ↑ a b c Luca Bindi: Atheneite, [Pd 2 ] [As 0.75 Hg 0.25 ], from Itabira, Minas Gerais, Brazil: crystal structure and revision of the chemical formula. In: The Canadian Mineralogist. 48, 2010, pp. 1149–1155, doi : 10.3749 / canmin.48.5.1149 .