Technical Resources
- Length Conversions
- Measures of Hardness
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- Scratch/Dig Specifications
- Surface Roughness
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- Relevant Links
Mineral Hardness Conversion Chart
There are many different scales / methods to measure mineral hardness. The most appropriate method for your application will depend on the material that you are measuring. The chart below is intended to give you a general reference of how some of these methods relate to others, using Mohs as the base measurement.
Hardness Comparison Reference Chart |
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| Mohs (MM) |
Knoop (HK) |
Brinell Indentation (HB Indentation) |
Brinell 10mm Standard 500 kgf (HB 500) |
Rockwell A-Scale (HRA) |
Vickers (HV) |
Material Example |
| 1 | -- | -- | -- | -- | 27 | Talc |
| 2 | -- | -- | -- | -- | 61 | Gypsum |
| 2.5 | 117 | -- | 90 | -- | 102 | - |
| 3 | 169 | 4.9 | 136 | -- | 157 | Calcite |
| 3.5 | 239 | 4.10 | 189 | 60 | 229 | - |
| 4 | 327 | 3.50 | -- | 66 | 315 | Fluorite |
| 4.5 | 436 | 3.08 | -- | 72 | 418 | - |
| 5 | 564 | 2.76 | -- | 77 | 535 | Apatite |
| 5.5 | 705 | 2.44 | -- | 81 | 669 | - |
| 6 | 839 | 2.27 | -- | 84 | 817 | Feldspar |
| 6.5 | 929 | -- | -- | 86 | 982 | - |
| 7 | -- | -- | -- | -- | 1161 | Quartz |
| 8 | -- | -- | -- | -- | 1567 | Topaz |
| 9 | -- | -- | -- | -- | 2035 | Corundum |
| 10 | -- | -- | -- | -- | -- | Diamond |
| "--" = converted value is outside of acceptable range for this scale. | ||||||