Zinc Borate (ZB) CAS NO.: 12767-90-7 Index /Grade Zinc Borate 2335( 2ZnO.3B2O3 3.5H2O) Super Grade Appearance White Crystal Powder B2O3% 45.0-48.0 ZnO% 36.0-39.0 Surface Water% ¡Ü 1 Loss on Ignition% ¡Ü 13.5-15.5 Mean Particle Diameter µm ¡Ü 7 Specific Gravity@25 .g/ml 2.7 Refractive Index 1.58