This table provides a comprehensive conversion between diamond powder grit, mesh, and micron sizes tailored for gemcutting applications. Use this guide to select the appropriate abrasive grade at each stage—from coarse shaping to fine polishing—to achieve optimal gemstone finishes.
Grit ratings are the standard in North America, mesh size designations are commonly used in Asian markets, micron measurements are prevalent across Europe, and FEPA grades are defined and maintained by the European Federation of Abrasives.
| Grit | Mesh | Micron (µm) | FEPA | Comments |
|---|---|---|---|---|
| 100 | 120–160 | 130-170 | D151 | Typical preforming grit for sintered laps |
| 160 (180) | 100-120 | 75-100 | D91 | Typical rough preforming grit for plated laps |
| 225 | 200–230 | 65–85 | D76 | |
| 270 | 230–270 | 50–65 | D54 | |
| 325 (360) | 270–325 | 40–55 | D46 | Typical preforming grit for plated laps |
| 600 | 400–500 | 30 | D36 | Plated laps: coarse cutting grit / Sintered laps: fine cutting grit |
| 800 | 600–700 | 25 | D25 | |
| 1,050 | 12–25 | 18 | D15 | |
| 1,200 | 1000–1200 | 15 | D10 | Typical fine cutting grit for plated laps |
| 1,800 | 6–12 | 9 | D9 | |
| 2,800 | 5–10 | 7 | D8 | |
| 3,000 (3k) | 4–8 | 6 | D6 | Typical coarse pre-polish option |
| 4,500 | 4–6 | 5 | D5 | |
| 5,000 | 2–6 | 4 | D4 | |
| 8,000 (8k) | 2–4 | 3 | D3 | Typical fine pre-polish option |
| 9,000 | 2–3 | 2.5 | D2 | |
| 14,000 (14k) | 0–2 | 1 | D1 | Industry standard commercial polish |
| 60,000 (60k) | 0–1 | 0.5 | D0.5 | Typical fine commercial polish |
| 100,000 (100k) | 0–0.5 | 0.25 | D0.25 | Competition level polish |
| 200,000 (200k) | 0–0.25 | 0.125 | D0.125 | Competition level polish |