Pirquitasite
| Pirquitasite | |
|---|---|
 |
|
| General and classification | |
| other names |
IMA 1980-091 |
| chemical formula | Ag 2 ZnSnS 4 |
|
Mineral class (and possibly department) |
Sulfides and sulfosalts |
|
System no. to Strunz and to Dana |
2.CB.15a ( 8th edition : II / C.06) 02.09.02.07 |
| Crystallographic Data | |
| Crystal system | tetragonal |
| Crystal class ; symbol | 4 2 or 4 |
| Space group | I 4 2 m or I 4 |
| Lattice parameters | a = 5.786 Å ; c = 10.829 Å Please complete the source as an individual reference |
| Formula units | Z = 2 Please complete the source as an individual reference |
| Twinning | polysynthetic |
| Physical Properties | |
| Mohs hardness | 4th |
| Density (g / cm 3 ) | 4.822 (calculated) |
| Cleavage | is missing |
| colour | brown-gray |
| Line color | Please complete |
| transparency | opaque |
| shine | metallic |
Pirquitasite is a very rare mineral from the mineral class of sulfides and sulfosalts . It crystallizes in the tetragonal crystal system with the chemical composition Ag 2 ZnSnS 4 and forms up to 0.5 mm large, irregularly shaped grains of brown-gray color that are fused with other minerals.
Etymology and history
The mineral was first found in 1982 by Z. Johan and P. Picot in the Pirquitas deposit in the Argentine province of Jujuy . They named it after the place where it was found.
classification
In the Strunz system , pirquitasite is classified among the sulfides and sulfosalts. It is counted among the sulphides with a ratio of metal to sulfur, selenium or tellurium of 1: 1. In the eighth edition , it formed a group with barquillite , briartite , černýite , famatinite , ferrokësterite , hocartite , kësterite , kuramite , luzonite , permingeatite , petrukite , sakuraiite , rhodostannite , stannite , toyohaite and velikite . In the ninth edition , the sulfides are also subdivided according to cations, where pirquitasite mt černýite, ferrokësterite, hocartite, idaite, kësterite, kuramite, mohite, stannite, stannoidite and velikite form a subgroup of metal sulfides with a ratio of metal to sulfur, selenium or tellurium of 1: 1 and zinc , iron , copper or silver .
In the systematics of minerals according to Dana it forms with stannite, černýite, briartite, kuramite, hocartite, sakuraiite, velikite, kësterite, ferrokësterite and barquillite the stannite subgroup of sulphides - including selenides and tellurides - with the composition Am Bn Xp, with ( m + n): p = 1: 1.
Modifications and varieties
Pirquitasite and hocartite form a mineral series in which zinc is exchanged for iron.
Education and Locations
Pirquitasite is formed by hydrothermal mineralization. It is associated with hocartite, pyrite , marcasite , wurtzite , Franckeit , miargyrite , aramayoite , chalcostibite , stannite , kesterite, rhodostannite and cassiterite .
In addition to the type locality in Argentina, only two other sites are known, the Cerro Rico near Potosí in Bolivia and the Toyoha mine near Sapporo in Japan .
Crystal structure
Pirquitasite crystallizes in the tetragonal crystal system in the space group I 4 2 m or I 4 with the lattice parameters a = 5.786 Å and c = 10.829 Å, as well as two formula units per unit cell .
See also
Individual evidence
literature
- Z. Johan, P. Picot: La pirquitasite, Ag 2 ZnSnS 4 , un nouveau membre du groupe de la stannite. In: Bull. Minéral. 1982, 105, pp. 229-235 ( abstract in American Mineralogist, p. 1249 ; PDF; 638 kB).
- Pirquitasit in: Anthony et al .: Handbook of Mineralogy , 1990, 1, 101 ( pdf ).