Allargentum
| Allargentum | |
|---|---|
 |
|
| General and classification | |
| chemical formula | (Ag, Sb) |
|
Mineral class (and possibly department) |
Sulfides and sulfosalts |
|
System no. to Strunz and to Dana |
2.AA.30 ( 8th edition : II / A.02) 02.02.01.02 |
| Crystallographic Data | |
| Crystal system | hexagonal |
| Crystal class ; symbol | 6 / mmm |
| Space group | P 6 3 / mmc |
| Lattice parameters | a = 2.94 Å ; c = 4.78 Å Please complete the source as an individual reference |
| Formula units | Z = 2 Please complete the source as an individual reference |
| Physical Properties | |
| Mohs hardness | 3.5 |
| Density (g / cm 3 ) | 10.0 |
| Cleavage | Please complete |
| colour | silver gray to yellowish |
| Line color | Please complete |
| transparency | opaque |
| shine | metallic |
Allargentum is a rarely occurring mineral from the mineral class of sulphides and sulphosalts and with a maximum silver content of around 99% silver, after solid silver, the mineral with the highest silver content. It crystallizes in the hexagonal crystal system with the chemical composition (Ag, Sb) and forms complex intergrowths with silver and small grains of silver-gray to yellowish color.
Etymology and history
The mineral was first found by Paul Ramdohr in Cobalt in the Canadian province of Ontario in 1949 . He defined allargentum as a hexagonal phase in the synthetic silver-antimony system. However, W. L. Petruk, L. J. Cabri, D. C. Harris, J. M. Stewart and L. A. Clark were able to show that the sample used by Ramdohr is a silver variety containing mercury and antimony. Instead, they named a silver-antimony mineral that they had also found in cobalt with the name Allargentum. This redefinition has also been recognized by the IMA.
classification
In the Strunz system , Allargentum is counted among the alloys and alloy-like compounds, a subgroup of sulfides and sulfosalts. After the 8th edition , it forms a group together with Dyskrasit . In the 9th edition it forms a separate subgroup of the compounds of semi-metals with copper, silver and gold .
In the Dana systematics , it forms with dyscrasite a subgroup of sulphides - including selenides and tellurides - with the composition A m B n X p , with a ratio of (m + n) to p of 3: 1.
Crystal structure
Allargentum crystallizes in the hexagonal crystal system in the space group P6 3 / mmc with the lattice parameters a = 2.94 Å and c = 4.78 Å as well as two formula units per unit cell .
properties
Allargentum and dyscrasite form a mixed crystal row .
Education and Locations
Allargentum is formed in silver- antimony ores. It is associated with silver, dyscrasite, broad-mainite , domeykite , kutinaite and stephanite .
In addition to the type locality in Canada, they are found in Catamarca and Córdoba in Argentina , Broken Hill and Mount Isa in Australia , Lishu in China , Benešov and Kutná Hora in the Czech Republic , Ylivieska in Finland , Bad Schlema in Germany , Narsaq in Greenland , Qostanai in Kazakhstan , Karasjok , Porsanger and Hemnes in Norway , Dalnegorsk in Russia , several mines in Sweden , Adrasman in Tajikistan and Ouray in the US state of Colorado . In total, Allargentum has been found at over 40 sites worldwide.
See also
literature
- Allargentum in: Anthony et al .: Handbook of Mineralogy , 1990, 1, 101 ( pdf ).
Web links
Individual evidence
- ↑ Webmineral - Mineral Species sorted by the element Ag (Silver)
- ^ Paul, Ramdohr: New ore minerals . In: Fortschr. Mineral. , 1949, 28, pp. 69-70, abstract in: American Mineralogist , 1954, 39, p. 691 pdf .
- ↑ W. L. Petruk, L. J. Cabri, D. C. Harris, J. M. Stewart and L. A. Clark: Allargentum, redefined . In: Canadian Mineralogist , 1970, 10, pp. 163-172, Abstract in: American Mineralogist , 1971, 56, p. 638 pdf .
- ^ New Dana Classification of Sulfide Minerals
- ↑ Mindat - Localities for Allargentum