Luster
Vitreous, Resinous
Vitreous, Adamantine
Pleochroism
-
Strong: purplish-red
Dispersion
0.020.02
0.005
1
👆🏻
Transparency
Transparent, Translucent
Transparent, Translucent, Transparent to opaque
Refractive Index
1.556-1.6001.762-1.778
1
3.25
👆🏻
Optic Character
-
-
Crystal System
-
Trigonal
Birefringence
0.024-0.0370.008
0
0.296
👆🏻
Clarity
Transparent
Transparent