Clay pottery: tips and groups

Antique clay "pottery" can be defined in a several different ways. One way of looking at the term is that it is a ceramic ware made of clay that was heated at a high temperature. Pottery can also be defined as the place where ceramics are made. In addition, "pottery" can refer to ceramics where the clay for pottery used is of a low grade and was fired at a lower heat, resulting in product that is not as hard as other grades of ceramics.

Groups of Clay Pottery
Earthenware is a low grade of clay pottery typically fired at temperatures below 2012 degrees Fahrenheit. The lower the temperature, the more porous the product will be. Extremely porous pottery is easier to chip and the less durable than other varieties. A glaze can be used to make the product water resistant.

Stoneware usually consists of about 90% clay and is fired at more than 2,100 degrees Fahrenheit. This results in strong, dense product that is durable and water resistant.

Porcelain is sometimes also called china because Chinese artisans had a centuries-long monopoly on the porcelain trade. The pottery clay used for porcelain is very high grade, whether it is white clay mixed with glass for soft paste or hard paste that uses the clay called kaolin. Like stoneware, porcelain is fired at more than 2,100 degrees Fahrenheit. When porcelain is thin, it is translucent.

As its name implies, bone china includes bone ash in its formula. Bone china was invented in England in the process of trying to create a substitute for porcelain. Bone china is fired twice, first at about 2336 degrees Fahrenheit and again at about 1976 degrees Fahrenheit. The resulting product is translucent, but does not quite reach the quality of porcelain.