Optical Properties
Luster
Vitreous, Vitreous, Waxy
Vitreous
Pleochroism
AbsentWalter Schumann
Not Available
Dispersion
None
Not Available
Transparency
Translucent, Translucent, Opaque, Translucent to nearly opaque
Gemmological Tables (2004)
Refractive Index
1.530-1.543
1.719-1.739
Optic Character
Not Available
Not Available
Crystal System
Trigonal
Trigonal
Birefringence
0.004
0.014-0.016
Clarity
Translucent
TransparentUlrich Henn and Claudio C. Milisenda
