Description Zinc Sulfide, 99.995% (Trace Metals Basis), Pieces 6mm & smaller, 250g For Research & Development Not for drug, human, animal, or food use Certificate of Analysis: Appearance (Color) White Appearance (Form) Pieces Assay (Trace Metals Basis) 99.995% ICP Analysis Confirms Zn component Particle Size 6mm & smallerTotal Metallic Impurities (ppm) As 8, Cu 2, Fe 2, Mg 1, Ni 2 CAS: 1314-98-3 FORMULA: ZnS