Iso 9001:2000 certificate (mgso4 .Nh2o n=0-7) From crystalline to powder Technical grade, feiilizer grade, food additive grade, pharm grade Appearance white small granular Main content 99.5% min Mgso4 48.59% min Mgo 16.27% min Mg 9.81% min Ph(5w/v%sol) 5-8 Ferron(fe) 0.0015% max Heavy metal (pb) 0.001 %max Arsenic(as) 0.0002% max