Black blue opal (a black opal with blue body color). Photo © Joel E. Arem, PhD, FGA. Used with permission.
Opaque Blue Play-of-Color Opal Stone Other
Black blue opal (a black opal with blue body color). Photo © Joel E. Arem, PhD, FGA. Used with permission.
Article: Appraising Opals
Credit: Joel E. Arem, PhD, FGA
| Gemstone | Opal Stone |
| Natural or man made | Natural |
| Gem State | Other |
| Color | Blue |
| Transparency | Opaque |
| Photo phenomena | Play of Color |