Stoneware goes back to about the 13th century when for the first time kilns could be brought to a temperature sufficient to cause vitrification. Vitrification is when the porous clay actually melts into a non-porous mass. This transformation from clay to stone occurs at about 1, degrees centigrade, or 2, degrees Fahrenheit. By introducing salt into the kiln at the height of the firing, just after vitrification has taken place, a hard glaze that is actually a type of glass, a sodium-alumina-silicate, is formed on the stoneware surface as the sodium in the salt and the silicates in the clay chemically combine. A proper glaze requires 2.
Your search has returned 41 results. Save your search - find out immediately when "Westerwald Pottery" is available at auction! Small Cobalt-decorated Stoneware Jug, Westerwald, Germany, 19th century, shaped bulbous body with incised and sprig-molded floral pattern, ringed neck, the spout with mask, ht. The George C.