Ceramics, made of kaolin (porcelain) and gres clay (gres), or stoneware, which can withstand very high temperatures. They are fired at 1400°C, a temperature at which the kaolin liquefies into the glass, closes the pores, and gives the ceramic mass a compact structure, with minimal absorbency (<0.5%) and great resistance to breakage and etching. The rendering of granite tiles in the Greek market, either as a paraphrase of the foreign term or as a reference to the hardness of granite, is abusive, as this category of tiles contains no trace of granite!