1 Optical Properties
1.1 Luster
1.2 Pleochroism
Weak: colorless-(greenish) yellow
Strong: pale lavender dark blueAnthony et al
1.3 Dispersion
1.4 Transparency
Gemmological Tables (2004) More from other references
TranslucentAnthony et al, Translucent
1.5 Refractive Index
1.650-1.677Not Available
1
3.25
1.6 Optic Character
Not Available
Not Available
1.7 Crystal System
Monoclinic Prismatic H-M Symbol (2/m) Space Group: P 21/a
Trigonal Ditrigonal Pyramidal H-M Symbol (3m) Space Group: R 3m
1.8 Birefringence
0.019-0.025Not Available
0
0.296
1.9 Clarity
TransparentUlrich Henn and Claudio C. Milisenda
TranslucentAnthony et al