SILICON
| Date | Clue |
|---|---|
| 2020-01-23 | Element of some chips |
| 2014-02-12 | Element in chips |
| 2012-04-23 | Element used to make semiconductors |
| 2012-01-22 | More than a quarter of the earth's crust, by mass |
| 2011-04-15 | More than a quarter of the earth's crust |
| 2010-11-24 | ___ Valley |
| 2008-05-23 | Element used to make semiconductors |
| 2004-08-21 | Element used to make semiconductors |
| 1995-07-20 | ____ Valley |