Bone china

Bone china is a type of porcelain that is made from bone ash, kaolin, and feldspar. It was developed by English potter Josiah Spode in the late 18th century, and remains renowned for its high levels of whiteness and translucency, as well as its mechanical strength and chip resistance.

History

The development of bone china is credited to Josiah Spode, who introduced it around 1796 in his factory in Stoke-on-Trent, England. Spode sought to create a type of porcelain that could rival the popular and expensive Chinese porcelain, which was imported in large quantities during the 18th century. The addition of bone ash gave the material a unique appearance and quality, which quickly gained popularity.

Composition

Bone china is made from 50% bone ash, 25% kaolin, and 25% feldspar. The bone ash, which is derived from animal bones, is what gives bone china its distinctive properties. The bones are heated to high temperatures to sterilize them and then ground into a fine powder. This bone ash is then mixed with the kaolin and feldspar to create the bone china mixture.

Production

The production of bone china involves several stages. First, the raw materials are mixed together to form a body slip. This slip is then formed into the desired shape using a variety of methods, including jiggering, casting, or pressing. After the shape is formed, it is allowed to dry before being fired in a kiln at a temperature of around 1200 degrees Celsius. This initial firing, known as the biscuit firing, hardens the piece and prepares it for glazing. After the biscuit firing, the piece is glazed and then fired again at a lower temperature. This second firing, known as the glost firing, gives the piece its characteristic glossy finish.

Characteristics

Bone china is known for its high levels of whiteness and translucency. It is also very strong and chip resistant, making it ideal for use in tableware. Despite its strength, bone china is also very delicate and requires careful handling.

Uses

Bone china is primarily used in the production of tableware and decorative items. It is highly prized for its beauty and durability, and is often used in high-end restaurants and hotels. It is also a popular choice for wedding gifts and collectibles.

See also

• Porcelain
• Josiah Spode
• Stoke-on-Trent