Tetrahedrite

Tetrahedrite is a copper antimony sulfosalt mineral with formula: . It is the antimony endmember of the continuous solid solution series with arsenic bearing tennantite. Pure endmembers of the series are seldom if ever seen in nature. Of the two, the antimony rich phase is more common. Other elements also substitute in the structure, most notably iron and zinc along with less common silver, mercury and lead. Bismuth also substitutes for the antimony site and bismuthian tetrahedrite or annivite is a recognized variety. The related, silver dominant, mineral species freibergite, although rare, is notable in that it can contain up to 18% silver.
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(n.)
A sulphide of antimony and copper, with small quantities of other metals. It is a very common ore of copper, and some varieties yield a considerable presentage of silver. Called also gray copper ore, fahlore, and panabase.
  

General Information:
 Chemical Formula:
(Cu,Fe)12Sb4S13
 Composition:
(Molecular Weight = 1,643.31 gm)
Iron 10.20 % Fe
Copper 34.80 % Cu
Antimony 29.64 % Sb
Sulfur 25.37 % S 
 Empirical Formula:
Cu9Fe2+3Sb4S13
 Name Origin:
Name is derived from its crystal form.
Physical Properties:
 Cleavage:
None
 Color:
iron gray, black, or steel gray.
 Density:
4.6 - 5.2, Average = 4.9
 Diaphaniety:
Opaque
 Habits:
Massive - Granular - Common texture observed in granite and other igneous rock., Massive - Uniformly indistinguishable crystals forming large masses.,
 Hardness:
3.5-4 - Copper Penny-Flourite
 Luminescence:
None.
 Luster:
Metallic
 Streak:
black
More details...

Eng: tetrahedrite
Urdu: خاکی کچ تانبا ۔ خاکی یا کالے رنگ کی فلزیَاتی چمک والی معدنی شے جو تانبے سُرمے اور گندھک کی آمیزش سے ترکیب پاتی ہے ۔