Ceramic Tiles can be formed either by pressing or extrusion.
Pressed tiles are made from clay paste that is compacted and formed by a high-pressure press. (Examples of these are floor tiles, wall tiles.)
Extruded tiles are formed by passing the raw materials in the form of a paste through a special tube. (Examples terracotta and klinker.) After forming, the tiles are dried to remove most of the water and then fired at the required temperature.

Tiles can be glazed or unglazed. Basically an unglazed tile contains the same colour and base raw material throughout the body and normally have no decoration or patterns.
A glazed tile consists of clay body (or bisque) covered with glaze, which is applied and fired separately. The glazes are formed from sand, clay, pieces of glass and oxide-based pigments to give the colour.
Bi-cottura
Double fired: the dried tiles are fired at temperatures approximately 750 degrees centigrade then the glazing and decorations are applied. They are then fired a second time at the same temperature as the first firing to stabilise the glaze.
Monocuttura tiles are strong, durable and easy to maintain.
Single fired: the glaze is applied directly to the green ware and the glaze of the body is fired together at temperatures approximately 1000-1250 degrees centigrade. Then the tiles are sorted to eliminate defective tiles. The body used can be white or yellow to reddish brown.

Wall Tiles
Double firing glazed obtained by pressing. Firing the shaped tile body at 750°C then the glaze and decoration is applied and fired a second time at the same temperature.

Terracotta
Unglazed tile on a red body. Obtained by extrusion. Single fired slow low temperatures water absorption 3-15%.

Klinker
Unglazed or glazed single fired, klinker is usually compact and is obtained by extrusion. Water absorption 0-7%.