1 Optical Properties
1.1 Luster
Adamantine
Waxy, Silky, Resinous, Greasy
1.2 Pleochroism
Moderate; cochineal-red to blood-red
Not Available
1.3 Dispersion
1.4 Transparency
OpaqueUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) Rarely transparentMore from other references
TranslucentHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
1.5 Refractive Index
2.792-3.0871.530-1.575
1
3.25
1.6 Optic Character
Not Available
Not Available
1.7 Crystal System
1.8 Birefringence
0.295-0.296Not Available
0
0.296
1.9 Clarity
OpaqueUlrich Henn and Claudio C. Milisenda
TranslucentHerve Nicolas Lazzarelli