Mineral - Okenite
Okenite
Chemical Properties
Mineral Class
Silicates
Toxicity
none
Formula
Ca₁₀[Si₆O₁₆|(Si₆O₁₅)₂] · 18 H₂O
Unit Cell
a=9.69 b=7.28 c=22.02 α=93° β=100° γ=111° Z=2
Physical Properties
Hardness
4.5 - 5
Streak
white
Density
Normal (2-3,5)
Cleavage
Perfect after {001}
Fracture
Tenacity
Elastic-flexible
Optical Properties
Color
whitecolorless
Birefringence
0.010
Luster
Vitreous,
Pearly
Transparency
translucent,
transparent
Pleochroism
Geomineralogical Properties
Crystal System
triclinic
Point Group
triclinic-pinacoidal - 1
Space Group
P 1 (2)
Habit
fibrous, felted, hair-like, spherical, acicular, radial
Formation
Hydrothermal as a secondary mineral formed by precipitation from silica-rich, calcium-containing solutions in cavities (vugs/geodes) within basaltic rocks
Paragenesis
Twinning
Rarity
Rather rare
Synonyms
Okenite
Composition
Elements
Mass
SiO₂
53.88
Al₂O₃
0.08
Fe₂O₃
0.01
CaO
27.61
SrO
0.27
Na₂O
0.12
K₂O
0.06
H₂O
18.02
India (Dana 1895)