Mineral - Cavansite
Cavansite
Chemical Properties
Mineral Class
Silicates
Toxicity
none
Formula
Ca[V⁴⁺O|Si₄O₁₀] · 4H₂O
Unit Cell
a=9.79 b=13.64 c=9.63 Z=4
Physical Properties
Hardness
3 - 4
Streak
whiteblueblue white
Density
Normal (2-3,5)
Cleavage
Distinct after {010}
Fracture
Tenacity
Brittle
Optical Properties
Color
blue
Birefringence
0.009
Luster
Vitreous
Transparency
translucent,
transparent
Pleochroism
X, Z: Farblos
Y: Blau
Geomineralogical Properties
Crystal System
orthorhombic
Point Group
orthorhombic-dipyramidal - 2/m 2/m 2/m
Space Group
Pnma (62)
Habit
leafy, acicular, prismatic, radial, tabular
Formation
In cavities of basaltic rocks under zeolite-facial conditions, from vanadium-rich hydrothermal solutions, at low temperatures (<200 °C) and moderate pH values
Paragenesis
Twinning
Rarity
Common
Synonyms
Cavansite
Composition
Elements
Mass
SiO₂
49.40
VO₂
17.10
CaO
11.50
H₂O
21.00
USA (Staples et al. 1973)