It is insoluble in water and acid, but dissolves in caustic soda and hydraulic fluoride acid without separation under high temperature. It can be filled in rubber to increase its physical characters, improve its inflexion tiredness, wearing, hardness of heating, responses of fixing and extending, elasticizing and adherence of compound materials. Because of its low cost and high white degree, it becomes the best white strengthening agent instead of carbon black. It is also widely used as a thickening in painting and printing, a filling in papermaking, a precipitator of fluorescent powder on the screen, a modal-releasing agent in casting, a sticking agent of synthetic resin, as well as a whitener of coating.