651.5 Mohs = 6.39 HRC
| Mohs | HRC |
|---|---|
| 636.5 Mohs | 6.24 |
| 641.5 Mohs | 6.29 |
| 646.5 Mohs | 6.34 |
| 651.5 | 6.39 |
| 656.5 Mohs | 6.44 |
| 661.5 Mohs | 6.49 |
| 666.5 Mohs | 6.53 |
651.5 Mohs = 6.39 HRC
1 HRC ≈ 10.2 HV · 1 HRB ≈ 1.8 HV · 1 Mohs ≈ 0.1 HV — approximate; real conversions vary by material per ASTM E140