1 Optical Properties
1.1 Luster
Vitreous
Vitreous, Adamantine, Vitreous, Adamantine
1.2 Pleochroism
Strong: pale lavender dark blueAnthony et al
None
1.3 Dispersion
1.4 Transparency
TranslucentAnthony et al, Translucent
Transparent, Transparent to translucent
1.5 Refractive Index
Not Available1.730-1.895
1
3.25
1.6 Optic Character
Not Available
Not Available
1.7 Crystal System
Trigonal Ditrigonal Pyramidal H-M Symbol (3m) Space Group: R 3m
Trigonal
1.8 Birefringence
Not AvailableNot Available
0
0.296
1.9 Clarity
TranslucentAnthony et al
Transparent