Granite: Dimensional surfaces, at minimum, cut and polished on one side (worked). Marble: Dimensional surfaces, at minimum, cut and polished on one side (worked). May include very small amounts of other calcareous stone defined by U.S. Customs and Border Protection as marble. Travertine: Dimensional surfaces, at minimum, cut and polished on one side (worked). Other Calcareous: Dimensional surfaces, at minimum, cut and polished on one side (worked), not otherwise classified as marble or travertine. Slate: Dimensional surfaces, at minimum, cut and polished on one side (worked), not classified as roofing material. Porcelain: Ceramic flags and paving, hearth or wall tiles, of a water absorption coefficient by weight <= 0,5 % (excl. refractory, mosaic cubes and finishing ceramics). Includes tiles and slabs.