Aikinite

Aikinite is a sulfide mineral of lead, copper and bismuth with formula PbCuBiS3. It forms black to grey or reddish brown acicular orthorhombic crystals with a Mohs hardness of 2 to 2.5 and a specific gravity of 6.1 to 6.8. It was originally found in 1843 in the Ural Mountains. It is named after Arthur Aikin (1773-1854), an English geologist.
See more at Wikipedia.org...

General Information:
 Chemical Formula:
PbCuBiS3
 Composition:
(Molecular Weight = 575.92 gm)
Copper 11.03 % Cu
Bismuth 36.29 % Bi
Lead 35.98 % Pb
Sulfur 16.70 % S 
 Empirical Formula:
PbCuBiS3
 Locality:
TL: Berezovsk near Ekaterinburg, Ural Mountains.
Physical Properties:
 Cleavage:
[010] Indistinct
 Color:
lead gray, grayish black, or reddish brown.
 Density:
6.1 - 6.8, Average = 6.44
 Diaphaniety:
Opaque
 Habits:
Acicular - Occurs as needle-like crystals., Massive - Uniformly indistinguishable crystals forming large masses.,
 Hardness:
2-2.5 - Gypsum-Finger Nail
 Luster:
Metallic
 Streak:
grayish black
More details...