TEST ITEMS SPECIFICATION APPEARANCE DARK YELLOW POWDER COLOR MATCHING DE 1.00 max CONTENT OF Fe2O3 86% min CONTENT OF SiO2+Al2O3 0.5% PH VALUE 3.1 DENSITY 4.1 g/ml SHADE CLOSE TO STANDARD OIL ABSORPTION 30-35% RESIDUE ON 320 MESH 0.008% max WATER SOLUBLE 0.3% max VOLATITE 1000 ° C 0.8% max TINTING STRENGTH 98-102 %