Mineral - Stephanite
Stephanite
Chemical Properties
Mineral Class
Sulfides and sulfosalts
Toxicity
none
Formula
Ag₅SbS₄
Unit Cell
a=7.84 b=12.47 c=8.54 Z=4
Physical Properties
Hardness
2 - 2.5
Streak
black
Density
Very Heavy (>6)
Cleavage
Imperfect after {010}
Fracture
conchoidal
Tenacity
Brittle
Optical Properties
Color
blackgray
Birefringence
Luster
Metallic
Transparency
opaque
Pleochroism
Geomineralogical Properties
Crystal System
orthorhombic
Point Group
orthorhombic-pyramidal - mm2
Space Group
Cmc2 1 (36)
Habit
acicular, prismatic, tabular, stair-shaped
Formation
(1) Primary hydrothermal as a late-stage formation in low- to moderately thermal veins
(2) Secondary through supergene enrichment in the cementation zone of silver deposits
Paragenesis
Twinning
Pseudohexagonal rotational twins after {110}
Rarity
Rarely
Synonyms
Stephanite
Composition
Elements
Mass
Ag
68.65
Sb
15.22
S
16.02
Chile (Palache et al. 1952)