Pleochroism
Weak or absentWalter Schumann
Not Available
Dispersion
None
Not Available
Transparency
Transparent, Translucent, Transparent to translucent
Translucent
Refractive Index
1.53-1.55
1.744-1.755
Optic Character
Not Available
Not Available
Crystal System
Triclinic
Orthorhombic
Birefringence
0.007-0.010
Not Available
Clarity
Transparent to translucent
Translucent