| Answer | Crossword Clue |
|---|---|
| OPAL | Stone made of hydrated silica |
| OPAL | Gemstone of hydrated silica |
| OPAL | It's a form of hydrated silica |
| turquoise | A semiprecious stone, typically opaque and of a greenish-blue or sky-blue color, consisting of a hydrated hydroxyl phosphate of copper and aluminum |
| OPAL | Silica stone |
