F 500

Unworked or semi-worked glass except glass used for construction purposes; fused quartz glass and fused silica as semi-finished products and semi-finished products manufactured therefrom, namely, pipes, [bars, boards, blocks all for use in chemical,] telecommunication,[ electrical, electronic and semiconductor industries;] unworked and semiworked fused quartz glass; semi-finished products from fused quartz glass, namely,[ ingots,] tubes,[ rods, discs, plates and rings, ]all for the manufacture of optical fibers; [vitreous silica fibers as a semi-finished product for use in chemical, electrical, telecommunication, and semiconductor industries and not for textile purposes]