COBALT
| Date | Clue |
|---|---|
| 2018-10-19 | Deep blue |
| 2018-02-25 | Shade of blue |
| 2017-02-04 | Permanent magnet metal |
| 2015-03-10 | Shade of blue |
| 2011-03-09 | Discontinued Chevrolet model |
| 2009-04-13 | Metal that gave its name to a shade of blue |
| 2005-12-18 | Element in magnetic alloys |
| 1997-10-19 | Metal found in meteors |
| 1996-07-18 | Shade of blue |