| Material | Knoop Hardness Scale |
|---|---|
| Wood – Pine | 10 |
| Copper | 120 |
| Limestone | 125 – 150 |
| Marble | 140 – 180 |
| Slate | 140 – 250 |
| Porcelain Fixtures & China | 400 – 500 |
| Glass & Ceramic | 400 – 550 |
| Ceramic Wall Tile | 450 – 550 |
| Porcelain Wall Tile | 500 – 650 |
| Porcelain Floor Tile | 500 – 650 |
| Marble Style Porcelain Floor Tile | 500 – 650 |
| Granite Style Porcelain Floor Tile | 500 – 650 |
| Granite | 550 – 650 |
| Quartz | 820 |
| Common Tool Steel | 700 – 900 |
| Tungsten Carbide | 2,000 |
| Diamond | 7,000 |