Mineral - Polybasite
Polybasite
Chemical Properties
Mineral Class
Sulfides and sulfosalts
Toxicity
none
Formula
(Ag,Cu)₁₆Sb₂₁₁
Unit Cell
a=26.17 b=15.11 c=23.89 β=90° Z=16
Physical Properties
Hardness
2 - 2.5
Streak
red
Density
Very Heavy (>6)
Cleavage
Imperfect after {001}
Fracture
conchoidal
Tenacity
Brittle
Optical Properties
Color
black
Birefringence
Luster
Metallic
Transparency
opaque
Pleochroism
Geomineralogical Properties
Crystal System
monoclinic , trigonal
Point Group
monoclinic-prismatic - 2/m
Space Group
C2/c (15)
Habit
tabular
Formation
(1) Primary hydrothermal, forming late in low- to medium-temperature veins, typically through precipitation from silver-rich, antimony-bearing hydrothermal solutions in the epithermal zone.
(2) Secondary, as a product of supergene enrichment in the cementation zone of silver deposits.
Paragenesis
Twinning
Rarity
Rarely
Synonyms
Polybasite
Composition
Elements
Mass
Ag
67.95
Cu
6.07
Fe
0.76
Sb
5.15
As
3.88
S
16.37
Canada (Palache et al. 1952)
Groups and Members
Pearceite-Polybasite-Group