663.5 Mohs = 6.5 HRC
| Mohs | HRC |
|---|---|
| 648.5 Mohs | 6.36 |
| 653.5 Mohs | 6.41 |
| 658.5 Mohs | 6.46 |
| 663.5 | 6.5 |
| 668.5 Mohs | 6.55 |
| 673.5 Mohs | 6.6 |
| 678.5 Mohs | 6.65 |
663.5 Mohs = 6.5 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