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Porcelain is often called china, or chinaware, because it was first made in China. Porcelain is characterized by whiteness, a delicate appearance, and translucence (ability to let light through). Because it is the hardest ceramic product, porcelain is used for electrical insulators and laboratory equipment. However, porcelain is known primarily as a material for high-quality vases and tableware, as well as for figurines and other decorative objects. The type of porcelain that is used for such purposes produces a bell-like ring when struck.

Porcelain differs from other types of ceramics in its ingredients and in the process by which it is produced. Two common types of ceramics–earthenware and stoneware–are made from a single natural clay, which is then fired (baked). In many cases, the object is coated with a glassy substance called glaze. Firing at a low temperature produces earthenware, a porous material. Earthenware can be made waterproof by glazing. Firing at a high temperature produces stoneware, a hard, heavy material. Stoneware is nonporous without glazing. Porcelain is basically made from a mixture of two ingredients–kaolin and petuntse. Kaolin is a pure white clay that forms when the mineral feldspar breaks down. Petuntse is a type of feldspar found only in China. It is ground to a fine powder and mixed with kaolin. This mixture is fired at high temperatures and the petuntse vitrifies–that is, it melts together and forms a nonporous, natural glass. The kaolin, which is highly resistant to heat, does not melt and therefore allows the item to hold its shape. The process is complete when the petuntse fuses itself to the kaolin.

There are three main kinds of porcelain: (1) hard-paste porcelain, (2) soft-paste porcelain, and (3) bone china. The differences between these types of porcelain are based on the material from which they are made. This material is called the body or paste.

A piece of porcelain is shaped on a potter’s wheel or in a mold. After this stage, the porcelain worker may decorate it by (1) surface modifications, (2) painting, or (3) transfer printing. Surface modifications are achieved by incising (carving), perforating (poking holes), and embossing (applying raised designs). A well-known method of embossing porcelain is to apply a mixture of water and clay, called slip, to the item with a brush. Relief designs (three-dimensional effects) are usually molded separately and then attached to the porcelain.

Painting the porcelain surface may be done in several ways. A deep blue made from the metal cobalt is the most dependable color used for underglazing. Cobalt blue has been widely used both in China and in Europe. Paints that are applied over the glaze are commonly called enamels. A large variety of enamel colors were perfected at an early period. Most of them are made from metallic oxides, such as iron, copper, and manganese. Enamel colors require a second firing to make them permanent.

Chinese decorators separated each color from the next with a dark outline, but European artists blended colors together with no separating line. In addition, Europeans used decorations purely for their artistic value, but Chinese decorations were symbolic. For example, a pomegranate design symbolized a wish for many offspring because a pomegranate has many seeds.

(Source: ancienthistory.mrdonn.org)