Section 13 Articles of stone, plaster, cement, asbestos, mica or similar materials; ceramic products; glass and glassware 69 Ceramic products 69 02 Refractory bricks, blocks, tiles and similar refractory ceramic constructional goods, other than those of siliceous fossil meals or similar siliceous earths. Commodity Code Description 69 02 10 Containing by weight, singly or together..., >50% Mg, Ca or Cr as MgO, CaO, Cr2O3 69 02 20 Containing by weight..., >50% alumina (Al2O3), silica (SiO2) 69 02 90 Other