Earthenware
Overview
 
Earthenware is a common ceramic
Ceramic
A ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous...

 material, which is used extensively for pottery
Pottery
Pottery is the material from which the potteryware is made, of which major types include earthenware, stoneware and porcelain. The place where such wares are made is also called a pottery . Pottery also refers to the art or craft of the potter or the manufacture of pottery...

 tableware and decorative objects.
Although body formulations vary between countries and even between individual makers, a generic composition is 25% ball clay
Ball clay
Ball clays are kaolinitic sedimentary clays, that commonly consist of 20-80% kaolinite, 10-25% mica, 6-65% quartz. Localized seams in the same deposit have variations in composition, including the quantity of the major minerals, accessory minerals and carbonaceous materials such as lignite...

, 28% kaolin, 32% quartz
Quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...

, and 15% feldspar
Feldspar
Feldspars are a group of rock-forming tectosilicate minerals which make up as much as 60% of the Earth's crust....

. Earthenware is one of the oldest materials used in pottery
Pottery
Pottery is the material from which the potteryware is made, of which major types include earthenware, stoneware and porcelain. The place where such wares are made is also called a pottery . Pottery also refers to the art or craft of the potter or the manufacture of 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 may sometimes be as thin as bone china
Bone china
Bone china is a type of soft-paste porcelain that is composed of bone ash, feldspathic material and kaolin. It has been defined as ware with a translucent body containing a minimum of 30% of phosphate derived from animal bone and calculated calcium phosphate...

 and other porcelain
Porcelain
Porcelain is a ceramic material made by heating raw materials, generally including clay in the form of kaolin, in a kiln to temperatures between and...

s, though it is not translucent and is more easily chipped.
Encyclopedia
Earthenware is a common ceramic
Ceramic
A ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous...

 material, which is used extensively for pottery
Pottery
Pottery is the material from which the potteryware is made, of which major types include earthenware, stoneware and porcelain. The place where such wares are made is also called a pottery . Pottery also refers to the art or craft of the potter or the manufacture of pottery...

 tableware and decorative objects.

Types of earthenware

Although body formulations vary between countries and even between individual makers, a generic composition is 25% ball clay
Ball clay
Ball clays are kaolinitic sedimentary clays, that commonly consist of 20-80% kaolinite, 10-25% mica, 6-65% quartz. Localized seams in the same deposit have variations in composition, including the quantity of the major minerals, accessory minerals and carbonaceous materials such as lignite...

, 28% kaolin, 32% quartz
Quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...

, and 15% feldspar
Feldspar
Feldspars are a group of rock-forming tectosilicate minerals which make up as much as 60% of the Earth's crust....

. Earthenware is one of the oldest materials used in pottery
Pottery
Pottery is the material from which the potteryware is made, of which major types include earthenware, stoneware and porcelain. The place where such wares are made is also called a pottery . Pottery also refers to the art or craft of the potter or the manufacture of 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 may sometimes be as thin as bone china
Bone china
Bone china is a type of soft-paste porcelain that is composed of bone ash, feldspathic material and kaolin. It has been defined as ware with a translucent body containing a minimum of 30% of phosphate derived from animal bone and calculated calcium phosphate...

 and other porcelain
Porcelain
Porcelain is a ceramic material made by heating raw materials, generally including clay in the form of kaolin, in a kiln to temperatures between and...

s, though it is not translucent and is more easily chipped. It is also less strong, less tough, and more porous than stoneware
Stoneware
Stoneware is a vitreous or semi-vitreous ceramic ware with a fine texture. Stoneware is made from clay that is then fired in a kiln, whether by an artisan to make homeware, or in an industrial kiln for mass-produced or specialty products...

, but is less expensive and easier to work. Due to its higher porosity
Porosity
Porosity or void fraction is a measure of the void spaces in a material, and is a fraction of the volume of voids over the total volume, between 0–1, or as a percentage between 0–100%...

, earthenware must usually be glazed
Ceramic glaze
Glaze is a layer or coating of a vitreous substance which has been fired to fuse to a ceramic object to color, decorate, strengthen or waterproof it.-Use:...

 in order to be watertight.

There are several types of earthenware, including
  • Creamware
    Creamware
    Creamware is a cream-coloured, refined earthenware created about 1750 by the potters of Staffordshire, England, which proved ideal for domestic ware. It was popular until the 1840s. It was also known as tortoiseshellware or Prattware depending on the colour of glaze used...

  • Delftware
    Delftware
    Delftware, or Delft pottery, denotes blue and white pottery made in and around Delft in the Netherlands and the tin-glazed pottery made in the Netherlands from the 16th century....

  • Faience
    Faience
    Faience or faïence is the conventional name in English for fine tin-glazed pottery on a delicate pale buff earthenware body, originally associated with Faenza in northern Italy. The invention of a white pottery glaze suitable for painted decoration, by the addition of an oxide of tin to the slip...

  • Tin-glazed pottery
    Tin-glazed pottery
    Tin-glazed pottery is a majolica pottery covered in glaze containing tin oxide which is white, shiny and opaque. The pottery body is usually made of red or buff colored earthenware and the white glaze was often used to imitate Chinese porcelain...

  • Victorian majolica
    Victorian majolica
    Victorian Majolica is earthenware pottery made in 19th century Britain, Europe and the USA with molded surfaces and colorful clear lead glazes.-History:...

  • Raku
  • Terra cotta
    Terra cotta
    Terracotta, Terra cotta or Terra-cotta is a clay-based unglazed ceramic, although the term can also be applied to glazed ceramics where the fired body is porous and red in color...


Firing

Earthenware is commonly biscuit
Bisque (pottery)
Bisque porcelain is unglazed, white ceramic ware Examples include bisque dolls.Bisque also refers to "pottery that has been fired but not yet glazed...

 (or "bisque") fired to temperatures between 1000 and 1150 °C (1800 and 2100 °F), and glost-fired (or "glaze-fired") from 950 to 1050 °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 biscuit temperatures may be 900 to 1050 °C (1,652 to 1,922 F) with glost temperatures in the range of 1040 to 1150 °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 colors ranging from white to red depending on the raw materials used.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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