bricks or tiles of small format with elevated thickness in which the composite mixture is composed of clay and low-quality kaolin, feldspathic flux and non-plastic materials. It is differentiated from vitrified tiles for the heterogeneity of the mixture and for its reduced vitrification but, as with vitrified tiles, is frost-resistant, impervious to chemical attack and has a notable mechanical resistance to bending. C. products are obtained through pressing or extrusion and are fired at temperatures above 1,200° C. with a cycle of several hours. They are used for both external and internal paving. The largest producer today continues to be Germany, the country in which it was invented around 1930.