--White exiguous acicular or oblique-pillar crystal. Smell-less,tast-bitter.Easily efflorescent at dry air.
--Speciific gravity is 1.68.
--Freely soluble in water . Soluble in its own water at 67.5oC.Slightly soluble in ethanol and glycerin.
--Dcomposing is heatedup.Lossing 4 crystal water at 70-80oC.About at 200oC,lossing all of its crystal water becomes anhydrous compounds.

Use:
--Mainly used in fertilizer, tanning, pringting and dyeing,activator,paper-making,plastic,porcelain,pigment matchmaking ,dynamite and fire-proof materials making .
--Can used in pringting and dyeing delaine as the aggravating reagent of calico or silk,and as filling up of wooden-cotton products.Be used as Epsom salts at medicine.