Magnesium Sulphate Heptahydrate 1.99% agricuture grade 2.transparent crystal 3.main contain 99%min 4.special ... rubber, palm trees ;2. In industries: used in tanning, porcelain, pigment, match, fireproof materials, Mg-salt, dyeing, medicine and food additives ... ,%,≥0.5Pb ,%,≤1Water insoluble,%,≤0.05 Magnesium Sulphate Heptahydrate fertilizer grade