690.5 Mohs = 6.77 HRC
| Mohs | HRC |
|---|---|
| 675.5 Mohs | 6.62 |
| 680.5 Mohs | 6.67 |
| 685.5 Mohs | 6.72 |
| 690.5 | 6.77 |
| 695.5 Mohs | 6.82 |
| 700.5 Mohs | 6.87 |
| 705.5 Mohs | 6.92 |
690.5 Mohs = 6.77 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