Chemical Specifications Appearance Colorless to white deliquescent crystals Assay (argentometric) Min 98% Chloride (Cl) Max 0.01% Sulphate (SO4) Max 0.05% Sulphide (S) Max 0.002% Heavy metal (as Pb) Max 0.001% Ammonium (NH4) Max 0.05% Iron (Fe) Max 0.005%