agri grade) Magnesium Sulfate(fertilizer) transparent crystal main contain 99%min Mg 9.81%min used as fertilizer...(agri grade) Magnesium Sulfate(fertilizer)Magnesium sulfate heptahydrate quality index:AppearanceWhite small granularMain content99% minMgSO448.59% minMgO16.27% minMg9.81% minPH(5W/V%Sol)5-9Ferron(Fe)0.002% maxChloride(CL)0.02% maxHeavy metal (Pb)0.0008% maxArsenic(As)0.0002% maxInsoluble0.01% maxSize (mm)0.1-1 0.2-3 1-4 ZIBO YICHI INTERNATION TRADING COMPANY IS A MANUFACTUREROF MAGNESIUM SULPHATE,WE HAVE OUR OWN FACTORY FOR MANUFACTURE CHEMICAL PRODUCTS