Brodtkorbit
| Brodtkorbit | |
|---|---|
| General and classification | |
| other names |
IMA 1999-023 |
| chemical formula | Cu 2 HgSe 2 |
|
Mineral class (and possibly department) |
Sulfides and sulfosalts |
|
System no. to Strunz and to Dana |
2.BD.55 ( 8th edition : II / B.06) 05/02/08/02 |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | 2 / m |
| Space group | P 2 1 / n |
| Lattice parameters |
a = 7.492 Å ; b = 4.177 Å; c = 7.239 Å β = 114.29 ° Please complete the source as an individual reference |
| Formula units | Z = 2 Please complete the source as an individual reference |
| Physical Properties | |
| Mohs hardness | 2.5 to 3 |
| Density (g / cm 3 ) | 7.77 |
| Cleavage | is missing |
| Break ; Tenacity | irregular |
| colour | dark gray |
| Line color | dark gray |
| transparency | opaque |
| shine | metallic |
Brodtkorbit is a very rarely occurring mineral from the mineral class of sulfides and sulfosalts . It crystallizes in the monoclinic crystal system with the chemical composition Cu 2 HgSe 2 and forms individual grains or aggregates of up to 100 μm in size and of a dark gray color.
Etymology and history
The mineral was found in 2002 by Werner H. Paar, Dan Topa, Andrew C. Roberts, Alan J. Criddle, Gerhard Amann and Ricardo J. Sureda in sample material from the Tumiñico Mine in the Sierra de Cacho in the Argentine province of La Rioja . They named it after the Argentine mineralogy professor Milka Kronegold de Brodtkorb .
classification
Brodtkorbit is in the classification according to Strunz to the sulphides and thio-salts having a ratio of metal to sulfur , selenium or tellurium, of greater than 1: counted own. 1 In the 9th edition of the system , a distinction is also made according to the cations , here Brodtkorbite is classified as a sulfide with a metal to sulfur ratio of greater than 1: 1 and the mercury or thallium contained . It forms its own group. In the 8th edition , the group around Brodtkorbite includes eukairite , henryite , imiterite , jalpait , mckinstryite , selenojalpait and stromeyerite in addition to this mineral .
According to the Dana system , brodtkorbite and imiterite form a subgroup of sulfides, selenides and tellurides with the composition A m B n X p and the ratio of (m + n) to p of 3: 2.
Education and Locations
Brodtkorbite seldom forms under hydrothermal conditions at temperatures below 112 ° C in polymetallic, selenium-rich deposits in calcite veins. It is associated with berzelianite , tiemannite , umangite , clausthalite , eukairite , naumannite , hematite and calcite .
So far only one site is known (as of September 2010), the type locality in Argentina.
Crystal structure
Brodtkorbite crystallizes in the monoclinic crystal system in the space group P 2 1 / n with the lattice parameters a = 7.492 Å , b = 4.177 Å, c = 7.239 Å and β = 114.29 ° as well as two formula units per unit cell .
See also
Individual evidence
literature
- Werner H. Paar, Dan Topa, Andrew C. Roberts, Alan J. Criddle, Gerhard Amann, Ricardo J. Sureda: The new mineral species Brodtkorbite, Cu 2 HgSe 2 , and the associated selenide assemblage from Tuminico, Sierra de Cacho, La Rioja, Argentina. In: The Canadian Mineralogist. 2002, 40, 1, pp. 225-237, doi : 10.2113 / gscanmin.40.1.225 .
- Brodtkorbit in: Anthony et al .: Handbook of Mineralogy , 1990, 1, 101 ( pdf ).