21 Fused quartz and pyrolytic boron nitride products in the form of crucibles, tubes, for use in the semiconductor, electronics, metallurgical, thin film and pharmaceutical industries; fused silica as a semi-finished product, namely, ingots, tubes, rods, plates and rings for general industrial and further manufacturing use, fused quartz as a semi-finished product, namely, ingots, tubes, rods, plates and rings for general industrial and further manufacturing use; articles made from fused silica, fused quartz or glass, namely, ingots tubes, rods, plates, and rings all for general industrial and further manufacturing use; house mark for a full line of boron nitride products, partly worked glass, fused quartz and fused silica, namely, ingots tubes, rods, plates, and rings all for general industrial and further manufacturing use