Freibergite
(repeating unit)Cu12Sb4S13 IMA symbol Fb[1] Strunz classification 2.GB.05 Crystal system Cubic Crystal class Hextetrahedral (43m)
H-M symbol: (4 3m) Space group I43m Identification Formula mass 1,929.46 g/mol Color Steel gray to black Crystal habit massive to well formed crystals Cleavage None Fracture Uneven Mohs scale hardness 3.5–4 Luster Metallic Streak reddish black Diaphaneity Opaque
H-M symbol: (4 3m)
Freibergite is a complex sulfosalt mineral of silver, copper, iron, antimony and arsenic with formula (Ag,Cu,Fe)12(Sb,As)4S13. It has cubic crystals and is formed in hydrothermal deposits. It forms one solid solution series with tetrahedrite and another with argentotennantite. Freibergite is an opaque, metallic steel grey to black and leaves a reddish-black streak. It has a Mohs hardness of 3.5 to 4.0 and a specific gravity of 4.85 to 5. It is typically massive to granular in habit with no cleavage and an irregular fracture.
The mineral was first described in 1853 from an occurrence in the silver mines of the type locality at Freiberg, Saxony.
References
- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- Mineral handbook
- Webmineral
- Mindat
![](http://upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/30px-Commons-logo.svg.png)
Wikimedia Commons has media related to Kenoargentotetrahedrite-(Fe).
- v
- t
- e