Mineral - Tremolite
Tremolite
Chemical Properties
Mineral Class
Silicates
Toxicity
none
Formula
□Ca₂Mg₅(Si₈O₂₂)(OH)₂
Unit Cell
a=9.86 b=18.05 c=5.28 β=105° Z=2
Physical Properties
Hardness
5 - 6
Streak
white
Density
Normal (2-3,5)
Cleavage
Perfect after {110}
Fracture
splintery
Tenacity
Brittle
Optical Properties
Color
whitegraygreenviolet
Birefringence
0.026
Luster
Vitreous,
Silky
Transparency
translucent,
transparent
Pleochroism
Geomineralogical Properties
Crystal System
monoclinic
Point Group
monoclinic-prismatic - 2/m
Space Group
C2/m (12)
Habit
blocky, fibrous, lath-shaped, acicular, prismatic, radial, columnar
Formation
(1) Contact metamorphism of siliceous carbonate rocks (dolomites) under low-grade conditions at temperatures up to approximately 500 °C.
(2) Regional metamorphism in the green schist facies resulting from the reaction of dolomite with quartz and water.
Paragenesis
Twinning
Rarity
Common
Synonyms
Tremolite
Composition
Elements
Mass
SiO₂
56.57
TiO₂
0.01
Al₂O₃
1.41
FeO
0.08
MnO
0.03
MgO
24.41
CaO
12.25
Na₂O
1.44
K₂O
0.68
F
1.52
Cl
0.05
H₂O
1.46
New York (Dana 1895)
Groups and Members
Amphibole-Supergroup
Calcium-Amphibole-Group
Tremolite-Subgroup