Gemstone | Crystal System | Density | Hardness | Refractive index | Treatments |
Corundum | trigonal | 4.00 | 9.0 | 1.762-1.770 | heat,
fracture filling; bulk diffusion with beryllium, coating, irradiation |
Color: Clarity: Transparent
to Opaque; Type II
Optic Character: DR Uniaxial Negative Cause of Color: Purple: Fe, Ti Cr in varying combinations Pink: Cr, possibly Ti Blue: Ti, Fe Green:Fe or Fe and Ti Yellow: Fe Orange: Fe or Color Centers Orangey Pink: Cr Color Change: Cr, V, Fe, Ti Fluorescence: Violet and Colr Change::Inert to Moderate to Strong Red Pink: Strong Orange-res Blue: Inert to Strong Red; dependent on Fe content Green:Inert Yellow: Inert to moderate orange, red or yellow Orange: usually inert Orangey Pink: May be strong orange-red Fracture : Concoidal Luster : Vitreous Cleavage : None Durability: Excellent Characteristics
for Identification: Localities:
|
Corundum
|