Chemistry:Argentopyrite
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| Argentopyrite | |
|---|---|
 Argentopyrite (from Schneeberg, Erzgebirge, Saxony, Germany) | |
| General | |
| Category | Sulfide mineral |
| Formula (repeating unit) | AgFe 2S 3 |
| Strunz classification | 2.CB.65 |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) (same H-M symbol) |
| Space group | P1121/n |
| Identification | |
| Color | Bronze-brown or gray-white; iridescent (many colors) |
| Crystal habit | Tabular prisms, pseudohexagonal or pseudo-orthorhombic, possibly pyramidally-terminated |
| Fracture | Uneven |
| Tenacity | Brittle |
| Mohs scale hardness | 3.5-4 |
| |re|er}} | Metallic |
| Streak | Grey |
| Diaphaneity | Opaque |
| Density | 4.25-4.27 |
| References | [1][2][3] |
Argentopyrite is a moderately rare sulfide mineral with the chemical formula AgFe
2S
3. It is one of the natural compounds of the MFe
2S
3 type, with M being caesium in very rare pautovite, copper in relatively common cubanite, potassium in rare rasvumite and thallium in rare picotpaulite. The type locality is Jáchymov in Czech Republic. Chemically similar mineral include sternbergite (dimorphous with argentopyrite), lenaite, AgFeS
2, and argentopentlandite, Ag(Fe,Ni)
8S
8.[1]
Crystal structure
Although previously assumed orthorhombic,[5] argentopyrite was later shown to be monoclinic, with structural relationship to cubanite. The most important feature of the argentopyrite structure are:[6]
- hexagonal close-packing of sulfur atoms
- presence of AgS
4 and FeS
4 tetrahedra in sheets displaying corner-sharing - presence of a cluster of four FeS
4 tetrahedra that share edges - presence of two iron sites, instead of one as in related species
- ordered-disordered ferrous-ferric nature of the mineral
References
- ↑ 1.0 1.1 "Argentopyrite - Argentopyrite: Argentopyrite mineral information and data". http://www.mindat.org/min-299.html. Retrieved 2016-03-07.
- ↑ "Argentopyrite". http://www.handbookofmineralogy.org/pdfs/argentopyrite.pdf. Retrieved 2016-03-07.
- ↑ Mineralienatlas
- ↑ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine 85 (3): 291–320. doi:10.1180/mgm.2021.43. Bibcode: 2021MinM...85..291W.
- ↑ Murdoch, J., and Berry, L.G., 1954. X-ray measurements on argentopyrite. American Mineralogist 39, 475-485
- ↑ Yang, H., Pinch, W.W., and Downs, R.T., Crystal structure of argentopyrite, AgFe
2S
3, and its relationship with cubanite. American Mineralogist 94, 1727-1730
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