| # | Clue | Answer As Given | Value | Round | Category | Air Date | Show |
|---|---|---|---|---|---|---|---|
| The Mohs scale is used to judge this quality of gems; a diamond rates a 10 | hardness | $400 | J | GEMSTONES | 2007-05-28 | #5241 | |
| A scratch test won’t reveal a mineral’s allergies, but this property | hardness | $200 | J | MINERALS | 1986-04-22 | #422 |