1 Optical Properties
1.1 Luster
1.2 Pleochroism
O = brownish red; E = yellowish red
Weak: colorless-(greenish) yellow
1.3 Dispersion
1.4 Transparency
OpaqueHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references
Gemmological Tables (2004) More from other references
1.5 Refractive Index
2.690-3.2201.650-1.677
1
3.25
1.6 Optic Character
Not Available
Not Available
1.7 Crystal System
Trigonal
Monoclinic Prismatic H-M Symbol (2/m) Space Group: P 21/a
1.8 Birefringence
1.9 Clarity
OpaqueHerve Nicolas Lazzarelli
TransparentUlrich Henn and Claudio C. Milisenda