Mineral - Variscite
Variscite
Chemical Properties
Mineral Class
Phosphates
Toxicity
none
Formula
AlPO₄ · 2H₂O
Unit Cell
a=9.82 b=9.63 c=8.56 Z=8
Physical Properties
Hardness
4.5
Streak
white
Density
Normal (2-3,5)
Cleavage
Distinct after {010}, indistinct after {001}
Fracture
splintery,
uneven
Tenacity
Brittle
Optical Properties
Color
redgreenbluecolorless
Birefringence
0.031
Luster
Vitreous,
Waxy
Transparency
translucent,
transparent
Pleochroism
Geomineralogical Properties
Crystal System
orthorhombic
Point Group
orthorhombic-dipyramidal - 2/m 2/m 2/m
Space Group
Pbca (61)
Habit
coarse, bulbous, spherical, massive
Formation
Secondarily, through the action of phosphate-bearing solutions near the surface on aluminum-rich rocks under oxidizing conditions
Paragenesis
Twinning
Rarity
Rather rare
Synonyms
Variscite
Composition
Elements
Mass
P₂O₅
44.73
V₂O₅
0.32
Al₂O₃
32.40
Fe₂O₃
0.06
Cr₂O₃
0.18
H₂O
22.68
Utah (Palache et al. 1952)
Groups and Members
Variscite-Group