Rochelle salt / Potassium Sodium Tartrate Cas no. 6381-59-5 MF:Na2C4H4O6.4H20 Appearance: Colorless crystal or white crystalline powder. Assay(dry):99.0% min. Chloride: 0.008% max. Sulfate: 0.05% max. Iron( Fe): 0.002% max. Heavy metals(Pb): 0.001% max. Insoluble matter in water: 0.05% max. Packing: 25kg woven bag lined with double layers kraft bag 1X20'FCL: 20MT (with pallet) or 23-24MT ( non-pallet package )