Mineral - Hemimorphite
Hemimorphite
Chemical Properties
Mineral Class
Silicates
Toxicity
none
Formula
Zn₄Si₂O₇(OH)₂· H₂O
Unit Cell
a=8.37 b=10.73 c=5.16 Z=2
Physical Properties
Hardness
4.5 - 5
Streak
white
Density
Normal (2-3,5)
Cleavage
Perfect after {110}, indistinct after {101} and {100}
Fracture
uneven
Tenacity
Brittle
Optical Properties
Color
greenblue
Birefringence
0.022
Luster
Vitreous,
Adamantine
Transparency
translucent,
transparent
Pleochroism
Geomineralogical Properties
Crystal System
orthorhombic
Point Group
orthorhombic-pyramidal - mm2
Space Group
Imm2 (44)
Habit
tabular, grape-shaped
Formation
Oxidation zone of Zinc deposits
Paragenesis
Twinning
Butterfly-shaped contact twins after {001}
Rarity
Rather rare
Synonyms
Hemimorphite
Composition
Elements
Mass
SiO₂
25.01
ZnO
67.42
H₂O
8.32
Virginia (Dana 1895)