... > SECTION XIII - ARTICLES OF STONE, PLASTER, CEMENT, ASBESTOS, MICA OR SIMILAR MATERIALS; CERAMIC PRODUCTS; GLASS AND GLASSWARE > CHAPTER 69 - CERAMIC PRODUCTS > I. GOODS OF SILICEOUS FOSSIL MEALS OR OF SIMILAR SILICEOUS EARTHS, AND REFRACTORY GOODS > 6903 Other refractory ceramic goods (for example, retorts, crucibles, muffles, nozzles, plugs, supports, cupels, tubes, pipes, sheaths, rods and slide gates), other than those of siliceous fossil meals or of similar siliceous earths > Containing, by weight, more than 50 % of alumina (Al2O3) or of a mixture or compound of alumina and of silica (SiO2) > Containing, by weight, 45 % or more of alumina (Al2O3)