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Porcelain is a ceramic material made by heating raw materials, generally including clay in the form of kaolin, in a kiln to temperatures between 1,200 °C (2,192 °F) and 1,400 °C (2,552 °F). The toughness, strength, and translucence of porcelain arise mainly from the formation of glass and the mineral mullite within the fired body at these high temperatures. Porcelain derives its present 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." However, the term porcelain lacks a universal definition and has "been applied in a very unsystematic fashion to substances of diverse kinds which have only certain surface-qualities in common" (Burton 1906). Porcelain is used to make table, kitchen, sanitary, and decorative wares; objects of fine art; and tiles. Its high resistance to the passage of electricity makes porcelain an excellent insulator. Dental porcelain is used to make false teeth, caps, crowns and veneers. 
Northern Song celadon porcelain, 10th century, China. 
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Flower centerpiece, 18th century, Spain. Earthenware is a common ceramic material, which is used extensively for pottery tableware and decorative objects. Although body formulations vary between countries and even between individual makers, a generic composition is 25% ball clay, 28% kaolin, 32% quartz, and 15% feldspar. Earthenware is one of the oldest materials used in pottery. While red earthenware made from red clays is very familiar and recognizable, white and buff colored earthenware clays are also commercially available and commonly used. Earthenware is commonly bisque, or biscuit, fired to temperatures between 1000 and 1150 °C (1800 and 2100 °F), and glost- (glaze-) fired from 950 to 1,050 °C (1,742 to 1,922 °F). However examples of the reverse  low biscuit and high glost firing  can also be found: this can be popular with some studio potters where bisque temperatures may be 900 to 1,050 °C (1,652 to 1,922 °F) with glost temperatures in the range of 1,040 to 1,150 °C (1,904 to 2,102 °F). The exact temperature will be influenced by the raw materials used and the desired characteristics of the finished ware. The higher firing temperatures are likely to cause earthenware to bloat. After firing, the body is porous and opaque with colours ranging from white to red depending on the raw materials used. Earthenware may sometimes be as thin as bone china and other porcelains, though it is not translucent and is more easily chipped. It is also less strong, less tough, and more porous than stoneware, but is less expensive and easier to work. Due to its higher porosity, earthenware must usually be glazed in order to be watertight 
Earthenware pottery
From Wikipedia, the free encyclopedia : Wholesale glass, porcelain and earthenware |
