A rock-forming mineral; industrially important in glass and ceramic industries; patter and enamelware; soaps; bond for abrasive wheels; cements; insulating compositions; fertilizer; tarred roofing materials; and as a sizing, or filler, in textiles and paper. In pottery and glass, feldspar functions as a flux. End-uses for feldspar in the world. include glass (70 percent) and pottery and other uses (30 percent).