21 Unworked or semi-worked glass, except glass used in building; glassware, namely, for lamp tubes, semiconductor machines; Fused silica as a semi-worked product, other than for building, and semi-finished products made therefrom, namely, tubes, poles, plates, blocks, rings; Synthetic fused quartz as a semi-worked product, other than for building, and semi-worked products made therefrom, namely, tubes, poles, plates, blocks, rings; Synthetic vitreous silica fibres, not for textile use; Synthetic black fused quartz as a semi-worked product, other than for building, and semi-worked products made therefrom, namely, tubes, poles, plates, blocks, rings; Synthetic opaque fused quartz as a semi-worked product, other than for building, and opaque semi-worked products made therefrom, namely, tubes, poles, plates, blocks, rings; Opaque synthetic vitreous silica fibres, not for textile use; Articles made from fused quartz or glass bodies, namely, ingots, tubes, rods, discs, plates and rings all for general industrial and further manufacturing use