Mineral - Bournonite
Bournonite
Chemical Properties
Mineral Class
Sulfides and sulfosalts
Toxicity
low
Formula
PbCu[SbS₃]
Unit Cell
a=8.15 b=8.69 c=7.79 Z=4
Physical Properties
Hardness
2.5 - 3
Streak
gray
Density
Heavy (3,5-6)
Cleavage
Imperfect after {010}, indistinct after {100} und {001}
Fracture
conchoidal,
uneven
Tenacity
Brittle
Optical Properties
Color
blackgray
Birefringence
Luster
Metallic
Transparency
opaque
Pleochroism
Geomineralogical Properties
Crystal System
orthorhombic
Point Group
orthorhombic-pyramidal - mm2
Space Group
Pmn2 1 (31)
Habit
prismatic, tabular
Formation
In hydrothermal ore deposits
Paragenesis
Twinning
Wheel-shaped rotational twins after {110}
Rarity
Common
Synonyms
Bournonite
Composition
Elements
Mass
Pb
42.34
Cu
12.80
Zn
0.04
Fe
0.27
Sb
24.44
S
19.58
Romania (Palache et al. 1952)
Groups and Members
Bournonite-Group