Mineral - Crocoite
Crocoite
Chemical Properties
Mineral Class
Chromates
Toxicity
middle
Formula
Pb[CrO₄]
Unit Cell
a=7.12 b=7.42 c=6.80 β=102° Z=4
Physical Properties
Hardness
2.5 - 3
Streak
orangeyellowyellow orange
Density
Very Heavy (>6)
Cleavage
Distinct after {110}, indistinct after {001} and {100}
Fracture
conchoidal
Tenacity
Brittle
Optical Properties
Color
redyellow
Birefringence
0.370
Luster
Greasy,
Adamantine
Transparency
translucent,
transparent
Pleochroism
Geomineralogical Properties
Crystal System
monoclinic
Point Group
monoclinic-prismatic - 2/m
Space Group
P2 1 /c (14)
Habit
lamellar, lath-shaped, acicular, prismatic, radial, tabular
Formation
Oxidation zone of lead deposits
Paragenesis
Twinning
Rarity
Rather rare
Synonyms
Crocoite
Composition
Elements
Mass
CrO₃
30.35
SiO₂
1.10
PbO
68.35
France (Palache et al. 1952)
Groups and Members
Monazite-Supergroup