What are the tiles

Ceramic tiles are made from a mixture of solutions of clay, sand and other natural materials by pressing or extrusion followed by a single or double firing, with or without enamelling.

Tiles are:

Pressed or extruded. Pressed tiles are made from a powder mix, molded under high pressure by a press. Extruded - from the dough-like mass, the formation of which occurs when passing through the extruder - the unit operating on the principle of meat grinder.
With a dense or porous base. The porosity of the tile depends on one of its main characteristics - water absorption: the greater the porosity of the substrate, the obviously higher the water absorption of the tile.
Glazed or not enamelled. Glazed tiles have a surface covered with a layer of colored glass, giving them not only a beautiful appearance, but also hardness and water resistance. Non-enameled tiles are uniform in composition and, as a rule, do not have decorative patterns.