stoneware (from the French grès 'sandstone')[1]​ is a ceramic paste, commonly composed of figuline clay or baked clay, quartz sand and degreasing materials - such as silica - and fluxes "Flux (chemistry)") - such as feldspar. Its main characteristics are its hardness and its low water absorption once fired at its glassy sintering temperature.

A certain variety of products can be manufactured with stoneware such as sanitaryware, sanitation pipes, tableware, pottery, among others, but without a doubt the largest field of application is the production of floor and wall tiles.

Stoneware has its origins around the year 1400 BC. C. between the Han dynasty and the Shang dynasty (1600 BC-1046 BC).[2]​[3]​[4]​[5]​.

In Europe, the production of stoneware began in the 19th century in Germany, in the Rhine region.[6]​ It did not begin to spread to other countries until the 19th century. Special success in the enamels, developing the salt glazes, to give them greater impermeability. In England it had great roots and from the century onwards an autonomous industry developed in Staffordshire. Famous potters at this center were John Dwight"), and Josiah Wedgwood.

The raw materials used to manufacture stoneware are divided into three categories: plastic materials, fluxing materials and inert materials.

Plastic materials are clay minerals, mainly kaolinitic or lithic, which provide sufficient plasticity in the presence of water to obtain, during the forming stage, a defined and stable shape. Chemically they provide aluminum, silicon and part of calcium, iron and titanium.

The fluxing materials are mainly feldspars and feldspathoids that in the firing phase form glassy phases that act as binders between the particles and reduce the final porosity of the product. They are chemical carriers of sodium, potassium, aluminum and silicon.

The inert materials are mainly siliceous sands that allow dimensional control of the pieces during the drying and firing stage, as well as favoring the degassing of any impurities (organic matter) that may be in the raw materials. They mainly provide silicon.

Porcelain stoneware is a type of stoneware with a higher degree of vitrification, which gives it less porosity, greater hardness and resistance. It is mainly used for soils exposed to large changes in temperature or water.