684.5 Mohs = 6.71 HRC
| Mohs | HRC |
|---|---|
| 669.5 Mohs | 6.56 |
| 674.5 Mohs | 6.61 |
| 679.5 Mohs | 6.66 |
| 684.5 | 6.71 |
| 689.5 Mohs | 6.76 |
| 694.5 Mohs | 6.81 |
| 699.5 Mohs | 6.86 |
684.5 Mohs = 6.71 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