Mineral - Proustite
Proustite
Chemical Properties
Mineral Class
Sulfides and sulfosalts
Toxicity
middle
Formula
Ag₃[AsS₃]
Unit Cell
a=10.79 c=8.69 Z=6
Physical Properties
Hardness
2 - 2.5
Streak
red
Density
Heavy (3,5-6)
Cleavage
Distinct after {10 1 1}
Fracture
conchoidal,
uneven
Tenacity
Brittle
Optical Properties
Color
red
Birefringence
0.296
Luster
Adamantine
Transparency
translucent,
transparent
Pleochroism
Geomineralogical Properties
Crystal System
trigonal
Point Group
ditrigonal-scalenohedral - 3 m
Space Group
R 3 c (167)
Habit
prismatic, Rhombohedron, Scalenohedron
Formation
(1) Primary hydrothermal as a late-stage formation in Ag-As-rich veins of the low-temperature sequence
(2) Secondary through enrichment in the oxidation or cementation zone of silver-bearing sulfide deposits
Paragenesis
Twinning
V-shaped contact twins after {10 1 4}, rotational trillings after {10 1 4}
Rarity
Rarely
Synonyms
Proustite
Composition
Elements
Mass
Ag
64.12
Sb
0.08
As
15.90
S
19.28
0.75
Canada (Palache et al. 1952)
Groups and Members
Proustite-Group