| Answer | Crossword Clue |
|---|---|
| ALUMINA | Oxide in rubies and sapphires |
| ALUMINA | Oxide found in rubies and sapphires |
| CORUNDUM | Sapphires and rubies. |
| GEMS | Emeralds, rubies, and sapphires |
| SRILANKA | Noted source of rubies and sapphires |
| LIME | Oxide used in cement and mortar. |
