Tellurobismuthite

Tellurobismuthite is a mineral form of bismuth telluride (Bi2Te3) with trigonal structure and lattice parameters a=0.439 nm and c=3.06 nm. There are natural cleavage planes in the (0001) direction as the crystal is effectively lamellar (layered) in that plane. The Mohs hardness is 2 and the density is 7815 kg.m-3. It is a dull grey colour, which is particularly lustrous on initial fracture.
See more at Wikipedia.org...

General Information:
 Chemical Formula:
Bi2Te3
 Composition:
(Molecular Weight = 800.76 gm)
Bismuth 52.20 % Bi
Tellurium 47.80 % Te
 Empirical Formula:
Bi2Te3
 Environment:
Gold and tellurium-bearing deposits.
 Locality:
Little Madrid Mine, Sylvanite district, Hidalgo County, New Mexico.
 Name Origin:
Named after its composition of tellurium and bismuth.
Physical Properties:
 Cleavage:
[0001] Perfect
 Color:
pale gray.
 Density:
7.815
 Diaphaniety:
Opaque
 Habits:
Massive - Fibrous - Distinctly fibrous fine-grained forms., Platy - Sheet forms (e.g. micas).,
 Hardness:
1.5-2 - Talc-Gypsum
 Luster:
Metallic
 Streak:
lead gray
More details...