Thai ruby (3.66 cts) and Sri Lankan sapphire (2.75 cts). Photo © Joel E. Arem, PhD, FGA. Used with permission.
Red Corundum Faceted Cushion Cut
Thai ruby (3.66 cts) and Sri Lankan sapphire (2.75 cts). Photo © Joel E. Arem, PhD, FGA. Used with permission.
Article: A Guide to Gem Classification
Credit: Joel E. Arem, PhD, FGA
| Gemstone | Corundum |
| Natural or man made | Natural |
| Gem State | Faceted |
| Color | Red, Blue |
| Transparency | Transparent |