| Index / Item | Zinc borate 2335 ( 2ZnO .3B2O3 . 3.5H2O ) | |
| Excellent grade | First grade | |
| Whiteness | 99 | 95 |
| Particle size , um | 3-6 | |
| 6-10 | ||
| 10-15 | ||
| Pb, PPM < | 10 | 20 |
| Cd, PPM < | 5 | 10 |
| ZnO , % | 37.0-40.0 | |
| B2O3, % | 46.0-48.0 | |
| H2O(hydrate), % | 13.0-15.5 | |
| Fineness (Residue on 45um sieve ) , % ≤ | 0.1 | |
| Specific gravity, g/cm3 | 2.67 | |
| Melting point °C | 980 | |
| Temp. of dehydration °C | 290 | |
| Refractive index | 1.58 | |






