Luster
Not Available
Vitreous, Pearly
Pleochroism
Colorless blueAnthony et al
Not Available
Dispersion
Not Available
Not Available
Transparency
Gemmological Tables (2004) More from other references
Not Available
Refractive Index
1.639-1.680
1.490-1.507
Optic Character
Not Available
Not Available
Crystal System
Not Available
Hexagonal
Birefringence
0.041
0.002-0.012
Clarity
TransparentUlrich Henn and Claudio C. Milisenda
Not Available