Novákit
| Novákit | |
|---|---|
 |
|
| General and classification | |
| chemical formula | (Cu, Ag) 21 As 10 |
|
Mineral class (and possibly department) |
Sulfides and sulfosalts |
|
System no. to Strunz and to Dana |
2.AA.15 ( 8th edition : II / A.01) 04/02/18/01 |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic prismatic; 2 / m , monoclinic sphenoid; 2 or monoclinic; m |
| Space group | C 2 (No. 5) , Cm (No. 8) or C 2 / m (No. 12) |
| Lattice parameters |
a = 16.27 Å ; b = 11.71 Å; c = 10.01 Å β = 112.74 ° Please complete the source as an individual reference |
| Formula units | Z = 4 Please complete the source as an individual reference |
| Physical Properties | |
| Mohs hardness | 3 to 3.5 |
| Density (g / cm 3 ) | 8.01 |
| Cleavage | Please complete |
| colour | gray, creamy white |
| Line color | black |
| transparency | opaque |
| shine | metallic |
Novákit is a very rare mineral from the mineral class of sulphides and sulphosalts with the chemical composition (Cu, Ag) 21 As 10 . It crystallizes in the monoclinic crystal system and forms aggregates with grains up to three centimeters in size. It also occurs as a vein in arsenic.
Etymology and history
The mineral was first found in 1961 by the Czech mineralogists Z. Johan and J. Hak in the type locality Černý Důl ( Schwarzenthal ) in the Giant Mountains ( Czech Republic ). They named the new mineral after the Czech mineralogist Jiří Novák .
classification
In the Strunz system , Novákite is classified under the sulphides and sulphosalts. It is counted among the alloys and alloy-like compounds. In the eighth edition it formed a group with algodonite , cuprostibite , domeykit , koutekit and kutinait . In the ninth edition , the alloys are also subdivided according to cations, where novákite can be found in the class of semi-metals with copper (Cu), silver (Ag) or gold (Au).
In the systematics of minerals according to Dana , it forms a subgroup of sulfides - including selenides and tellurides - with the composition Am Bn Xp, with (m + n): p = 2: 1.
Crystal structure
Novákite crystallizes in the monoclinic crystal system in the space group C 2 (space group no. 5) , Cm (no. 8) or C 2 / m (no. 12) with the lattice parameters a = 16.27 Å , b = 11.71 Å , c = 10.01 Å and β = 112.74 °, as well as four formula units per unit cell .
Education and Locations
Novákite forms in hydrothermal veins rich in carbonate. Depending on where it was found, it is associated with arsenic , arsenol amprite , koutekite , silver , lollingite , chalcosine , skutterudite , chalcopyrite , bornite , uraninite , calcite , algodonite , djurleit and domeykite .
Only a few sites are known. In addition to the type locality, the mineral was also found in Náchod ( Czech Republic ) and in Montrose in the US state of Colorado .
See also
literature
- Novákit in: Anthony et al .: Handbook of Mineralogy , 1990, 1, 101 ( pdf )
- Z. Johan, J. Hak: Novákite, (Cu, Ag) 4 As 3 , a new mineral . In: American mineralogist , 1961, 46, pp. 885-891 ( pdf ).
Web links
- Mineral Atlas: Novákit
- Mindat - Novákite (English)