POTTERY TYPES

Clay, pottery, earthenware, terracotta, stoneware – are they all the same thing?

Clay is essentially the raw material. It is a mix of mineral substances that occur in sedimentary rocks and soils. It is soft when moist, but hardens when heated. Item made from clay become earthenware when it is fired at relatively low temperatures (where it does not become vitreous).

Pottery comprises three distinctive types of wares:  earthenware, stoneware, and porcelain.

The first type, earthenware, has been manufactured using the same basic techniques since ancient times. Earthenware is basically composed of clay or a blend of clays that are baked firm. Because it is fired at low heat, the pottery clay does not lose its porous nature and does not become translucent. Earthen wares are porous and therefore not as strong as stone wares. Earthenware can be glazed, but it will never be as hard as stoneware-glazed surface. An earthenware-glazed dish will scratch or chip more easily than the harder surface of stoneware.

The second type of pottery, called stoneware is earthenware relatively rich in vitreous material and fired at so high a temperature (about 2185 degrees Fahrenheit) that it becomes as hard as stone and non-porous. Stoneware is extremely strong and will not absorb water. Because stoneware is nonporous, it does not require a glaze; when a glaze is used, it serves a purely decorative function. Stoneware dishes can be used in conventional and microwave ovens.

Porcelain was invented by the Chinese and consists of feldspathic material incorporated in a stoneware composition. Porcelain is a very hard white ceramic which has been manufactured in China since the 600s, and in Europe since the 1700s. Porcelain, also called china, is fired using very high heat, resulting in a white, nonporous pottery.  Porcelain is translucent; stoneware and earthenware is not.

Terracotta is an Italian word for “baked earth”. It refers to type of brownish, unglazed porous earthen wares.