| Mineral | Opal |
|---|---|
| Formula | SiO2 • n(H2O) |
| Crystal Form | Amorphous/Amorphous |
| Cleavage | None |
| Color | White, Yellow, Red, Brown, Blue |
| Density | 1.9 – 2.3 g/cm3 |
| Diaphaneity | Transparent toTranslucent to Opa |
| Fracture | Conchoidal |
| Hardness | 5.5 - 6.0 |
| Lustre | Vitreous - Dull |
| Streak | White |
| Dana 8 Class | 75.2.1.1 |
| Strunz Class | IV/D.01-80 |
| Mindat | mindat.org |
| WebMineral | WebMineral |
| ID | 67 |