Mineral - Clinochlore
Clinochlore
Chemical Properties
Mineral Class
Silicates
Toxicity
middle
Formula
(Mg,Fe²⁺,Al)₃[(OH)₂|AlSi₃O₁₀]·(Mg,Fe²⁺,Al)₃(OH)₆
Unit Cell
a=5.35 b=9.27 c=14.27 β=96° Z=2
Physical Properties
Hardness
2 - 2.5
Streak
greenblueblue green
Density
Normal (2-3,5)
Cleavage
Perfect after {001}
Fracture
smooth
Tenacity
Inelastic-flexible
Optical Properties
Color
brownredyellowgreencolorless
Birefringence
0.011
Luster
Vitreous,
Pearly
Transparency
translucent,
transparent
Pleochroism
Geomineralogical Properties
Crystal System
monoclinic
Point Group
monoclinic-prismatic - 2/m
Space Group
C2/m (12)
Habit
leafy, radial, tabular
Formation
(1) Metamorphic through the transformation of magnesium-rich minerals (such as olivine, pyroxene, or biotite) under low- to medium-grade conditions of the green schist facies.
(2) Hydrothermal as an alteration product of mafic rocks and in alpine fissure fillings through precipitation from magnesium-rich aqueous solutions.
(3) Metasomatic in contact zones between silica-rich and magnesium-rich rocks (e.g. chlorite schist formation).
Paragenesis
Twinning
Rarity
Rather rare
Synonyms
Clinochlore
Composition
Elements
Mass
SiO₂
33.83
Al₂O₃
12.95
Fe₂O₃
2.25
FeO
3.02
MgO
34.94
H₂O
13.11
Austria (Dana 1895)
Groups and Members
Chlorite-Group