Aluminium Oxide Chromium Vanadium doped
Al2O3:CrV
Chemical name
Aluminium Oxide Chromium Vanadium doped
Mineral name
Sapphire (Corundum)
Chemical formula
Al2O3:CrV
Crystal system
trigonal
Crystal Class
ditrigonal-scalenohedral (-3 2/m)
Space Group
R-3c
Unit cell
a [Å]:4.74
b [Å]:4.74
c [Å]:12.97
Formula units
Z=6
Twinning
polysynthetic twins common
Mohs hardness
9
Density [g/cm3]
3.9 - 4.1
Cleavage
none
Fracture / Tenacity
brittle, uneven to conchoidal
Color
green
Streak
white
Transparency
transparent, translucent to opaque
Optical character
uniaxial (-)
Refractive Index
nω=1.769; nε=1.761
Birefringence δ
0.009
Pleochroism δ
distinct
Other
luminescent (rare but very strong)