1 Optical Properties
1.1 Luster
Vitreous
Waxy, Silky, Resinous, Greasy
1.2 Pleochroism
Strong: pale lavender dark blueAnthony et al
pale greenish yellow.
1.3 Dispersion
1.4 Transparency
TranslucentAnthony et al, Translucent
Translucent
1.5 Refractive Index
Not Available1.530-1.575
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
Monoclinic Domatic H-M Symbol (m) Space Group: Cm
1.8 Birefringence
Not AvailableNot Available
0
0.296
1.9 Clarity
TranslucentAnthony et al
Translucent