Argentopyrite
| Argentopyrite | |
|---|---|
 |
|
| General and classification | |
| other names |
Silver gravel |
| chemical formula | AgFe 2 S 3 |
|
Mineral class (and possibly department) |
Sulfides and sulfosalts |
|
System no. to Strunz and to Dana |
2.CB.65 ( 8th edition : II / C.14) 02.09.13.02 |
| Crystallographic Data | |
| Crystal system | orthorhombic (pseudohexagonal) |
| Crystal class ; symbol | orthorhombic-dipyramidal 2 / m 2 / m 2 / m |
| Space group | Pmmn |
| Lattice parameters | a = 6.64 Å ; b = 11.47 Å; c = 6.45 Å |
| Formula units | Z = 4 |
| Twinning | parallel [001] |
| Physical Properties | |
| Mohs hardness | 3.5 to 4 |
| Density (g / cm 3 ) | measured: 4.25; calculated: 4.27 |
| Cleavage | no |
| Break ; Tenacity | uneven; brittle |
| colour | gray-white, tinged with variegated colors |
| Line color | Gray |
| transparency | opaque |
| shine | Metallic luster |
Argentopyrite (also silver gravel ) is a rarely occurring mineral from the mineral class of " sulfides and sulfosalts ". It crystallizes in the orthorhombic crystal system with the composition AgFe 2 S 3 , so from a chemical point of view it is a silver - iron sulfide.
Argentopyrite is opaque in every form and develops mostly thick tabular, pseudo-hexagonal crystals , but also granular mineral aggregates of initially gray-white color and metallic luster . When exposed to the air, the mineral becomes colored and iridescent over time. Argentopyrite leaves a gray line on the marking board .
Etymology and history
Argentopyrite was first found near Jáchymov ( Sankt Joachimsthal ) in the Czech Republic and described in 1866 by Wolfgang Sartorius von Waltershausen (1809–1876), who named the mineral after its silver content (Latin: Argentum ) and its similarity to pyrite .
Type material of the mineral is among others in the Royal Ontario Museum in Toronto , Canada (register no .: M13001 ) and in the collection of the Geoscientific Museum of the University of Göttingen (register no .: GZG.MIN.2.3.75.4 / UG023-025 ).
classification
In the meanwhile outdated, but still in use 8th edition of the mineral classification according to Strunz , the argentopyrite belongs to the mineral class of "sulfides and sulfosalts" and there to the department of "sulfides with the molar ratio of metal: sulfur (selenium, tellurium) = 1: 1", where, together with cubanite , enargite , sternbergite and stibioenargite, it forms the unnamed group II / C.14 .
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 assigns argentopyrite to the class of "sulfides and sulfosalts" and there in the department of "metal sulfides, M: S = 1: 1 (and similar) ”. However, this section is further subdivided according to the type of cations contained in the compound, so that the mineral is classified according to its composition in the sub-section "with zinc (Zn), iron (Fe), copper (Cu), silver (Ag), etc." is to be found where it forms the unnamed group 02.CB.65 together with Sternbergit member .
The systematics of minerals according to Dana also assigns argentopyrite to the class of "sulphides and sulphosalts" and there in the category of "sulphide minerals". Here it is together with cubanite and isocubanite in the " cubanite group " with the system no. 02.09.13 within the sub-section of " Sulphides - including selenides and tellurides - with the general composition A m B n X p , with (m + n): p = 1: 1 ".
Modifications and varieties
The compound is dimorphic and occurs in nature in addition to the orthorhombic crystallizing argentopyrite also as orthorhombic, but in a different space group crystallizing starbergite .
Education and Locations
(field of view: 5 mm)
Argentopyrit formed by hydrothermal processes in silver-bearing ore - courses . There it occurs in paragenesis primarily with native silver and sternbergite, but also with sulfide minerals such as prostite , pyrargyrite , pyrite , pyrostilpnite , stephanite , xanthocone , nickel skutterudite as well as calcite , dolomite and quartz .
In addition to its type locality Jáchymov, argentopyrite was also found in the Czech Republic near Měděnec ( copper mountain ). So far (as of 2010) argentopyrite has been detected at around 40 sites worldwide, including Broken Hill and the "George Fisher Mine" near Mount Isa in Australia; near Colquechaca in the Bolivian Department of Potosí; in several regions of Germany and France ; Greece ; Italy ; on Honshū in Japan; in the "Silvana Mine" near Sandon in the Canadian province of British Columbia ; Kazakhstan ; Morocco ; Norway ; near Hüttenberg (Carinthia) in Austria; Romania ; of Switzerland ; Slovakia ; in the "Tynebottom Mine" in the English district of Tynedale and in the "Black Creek Mine" ( Alaska ) and in the "Slate Creek District" ( Idaho ) in the USA.
Crystal structure
Argentopyrite crystallizes orthorhombically in the space group Pmmn with the lattice parameters a = 6.64 Å ; b = 11.47 Å and c = 6.45 Å and 4 formula units per unit cell .
See also
Individual evidence
- ↑ Webmineral - Argentopyrite (English)
- ↑ a b c d Hugo Strunz , Ernest H. Nickel: Strunz Mineralogical Tables . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p. 83 .
- ↑ John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols: Argentopyrite , in: Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 62.4 kB )
- ^ W. Sartorius von Waltershausen: Some subsequent remarks about the silver gravel . In: News from the K. Society of Sciences and the Georg August University (1866) (PDF 140.4 kB; p. 2)
- ↑ Typmineral catalog Germany - Argentopyrite ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. , managed by the University of Hamburg
- ↑ Mindat - Localities for Argento Pyrite
literature
- Petr Korbel, Milan Novák: Encyclopedia of Minerals . Nebel Verlag GmbH, Eggolsheim 2002, ISBN 3-89555-076-0 , p. 32 .
Web links
- Mineral Atlas: Argentopyrite (Wiki)