| Clue | Source | Date |
|---|---|---|
| Silvery-white metallic element; symbol Rb (8) | Mirror Quiz | 02 Jan 2026 |
| Silver-white element used in radio vacuum tubes (8) | ||
| Element of hillbilly language overheard | ||
| Polish ID, I with hesitation, gets something like potassium (8) | ||
| Rare metallic element | The Times Concise | 17 Jun 2015 |