Luster
Pleochroism
Dispersion
Transparency
Refractive Index
Optic Character
Crystal System
Birefringence
Clarity
TranslucentWalter Schumann
TranslucentWalter Schumann
Trichroism: green light brown dark brownHerve Nicolas Lazzarelli
TransparentUlrich Henn and Claudio C. Milisenda