Ginna's Quick Guide to Ceramics


Porcelain is a ceramic material made by heating raw materials, generally including clay in the form of kaolin, in a kiln to Cone 10 t Cone 14 (1200-1400C/2192-2552F).
(We do not fire porcelain.)

Porcelain, which some consider to be a type of stoneware, generally thought to have originated in China. The European search for the secret of porcelain manufacture ended in 1708 with the discovery of a combination of ingredients, including Colditz clay (a source of kaolinite), calcined alabaster, and quartz, that produced a hard, white, translucent porcelain.vase

Porcelain is distinguished as being whiter than stoneware and always vitreous. Kaolin, or china clay, has a lower content of impurities than many other clays. It is also fired to a vitreous state, transforming the constituent silica into glass. Some porcelain bodies are translucent after firing.

The toughness, strength, and translucence of porcelain arise mainly from the glass formed within the clay body by the silicite minerals (mullite) at these very high temperatures.

Porcelain derives its name from old Italian porcellana (cowrie shell) because of its resemblance to the translucent surface of the shell. Porcelain can informally be referred to as "china" in some English-speaking countries, as China was the birth place of porcelain making.

Properties associated with porcelain include low permeability and elasticity; considerable strength, hardness, glassiness, brittleness, whiteness, translucence, and resonance; and a high resistance to chemical attack and thermal shock.

For the purposes of trade, the Combined Nomenclature of the European Communities defines porcelain as being

"completely vitrified, hard, impermeable (even before glazing), white or artificially coloured, translucent (except when of considerable thickness) and resonant."

One should keep in mind that the term porcelain lacks a universal definition and is often applied in broadly to diverse kinds of substances which have only certain surface-qualities in common.