Thin slabs made from clays,silica, fluxes, colouring and other mineral raw materials,generally used as coverings for floors, walls or facades.They are prepared by grinding, sieving, mixing,moistening etc, and are shaped by pressing, extruding,casting or other processes, usually at room temperamre.They are then dried and subsequently fired at a high temperature. Tiles may be glazed (CL), unglazed(UGL) or engobed and are incombustible and unaffected by light. Dependi~ on degree of vitrification, water absorption may vary. A low water absorption tile is also called porcelain tile. An extremely low water absorption tite is called .a fully vitrified tile and this may be either in polished or unpolished form.