Lithium Aluminium Silicate
LiAl(SiO3)2
Chemical name
Lithium Aluminium Silicate
Mineral name
Spodumen
Chemical formula
LiAl(SiO3)2
Crystal system
monoclinic
Crystal Class
monoclinic-prismatic (2/m)
Space Group
C2/c
Unit cell
a [Å]:9.52
b [Å]:8.32
c [Å]:5.25
Formula units
Z=4
Frequent crystal surfaces
{100}, {010}, {110}
Twinning
common on {100}
Mohs hardness
6.5 - 7
Density [g/cm3]
3.1 - 3.2
Cleavage
perfect on {110}
Fracture / Tenacity
uneven to conchoidal
Color
colorless to grayish-white, rose to violett, green
Streak
white
Transparency
transparent to translucent
Optical character
biaxial (+)
Refractive Index
nα=1.648-1.661; nβ=1.655-1.670; nΥ=1.662-1.670
Birefringence δ
0.014 - 0.018
Pleochroism δ
strong
Other
often fluorescent (kunzite)