Copper Hydroxy Carbonate
Cu3(CO3)2(OH)2
Chemical name
Copper Hydroxy Carbonate
Mineral name
Azurite
Chemical formula
Cu3(CO3)2(OH)2
Crystal system
monoclinic
Crystal Class
monoclinic-prismatic (2/m)
Space Group
P2_1/c
Unit cell
a [Å]:5.01
b [Å]:5.85
c [Å]:10.35
Molecular weight [g/mol]
344,65
Formula units
Z=2
Twinning
rare on {-101}, {-102}, {001}
Mohs hardness
3.5 - 4
Density [g/cm3]
3.77
Cleavage
nearly perfect on {011}, distinct on {100}, indistinct on {110}
Fracture / Tenacity
conchoidal
Color
(azure-)blue, very dark to pale blue, pale blue in transmitted light
Streak
light blue
Transparency
transparent to translucent
Optical character
biaxial (+)
Refractive Index
nα=1.730; nβ=1.758; nΥ=1.838
Birefringence δ
0.108
Pleochroism δ
moderate to strong
Piezoelectric crystals
 
T(c) [°C]
nε = 1.568–1.602