Histories of UK potters and pottery manufacturers

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Last updated: 1st August 2011

POTTERY BODIES AND PASTES

Body

The physical composition of a ceramic as opposed to other components such as the glaze and decoration.  For example, ‘an earthenware body’. Used as a generic term for the raw material from which a ceramic has been made.  Terra-cotta, earthenware, stoneware, soft- and hard-paste porcelain and bone china are all ‘bodies’ but with different chemical compositions and/or physical processing. ‘Paste’ is a related term, referring more specifically to the clay mixture used to form the ceramic item. For any ceramic body, there could be any number of suitable ‘pastes’ each differing slightly in composition and properties. See Paste.

Biscuit

The ceramic body after one firing, but before decoration or glazing.

Bisque

A once-fired, but unvitrified and unglazed porcellaneous body used mainly for busts and figurines. Bisque figurines usually have a white to ivory body with a fine, smooth surface texture.

Bone china

A soft-paste porcellaneous body that includes calcined animal bone (up to 50%) in addition to china clay and china stone, the calcined bone adding whiteness, translucency and strength. Although the inclusion of bone ash in pastes pre-dates 1794, its adoption by Josiah Spode from about 1794 marked the introduction of ‘bone china’ and by about 1820 it had become the standard porcellaneous body in the United Kingdom. Bone china is an attractive, warm, slightly creamy body ideally suited to tablewares.

China

A generic term used to describe porcellaneous (white, translucent) bodies as opposed to earthenware or ‘pottery’.  The term originally described the hard-paste porcelain imported from China, but gradually came to be used for all similar bodies.

Dry body (stoneware)

A generic term for fine-textured, vitrified stoneware that needs no glaze to retain liquids – thus the name ‘dry-body’.

Earthenware

A ceramic body fired at a comparatively low temperature to produce a generally heavy, opaque, porous body. Earthenware is a general descriptive name for any opaque, glazed ceramic body made from ‘clay’. It is distinguished from porcelain by being opaque (usually) rather than translucent, and from stoneware by being porous rather than having a vitrified body.

Felspar porcelain

A refined paste developed by Josiah Spode at the end of the 18th century for bone china.

Felspathic Earthenware

An improved earthenware body containing feldspar.  Feldspathic earthenware is a moderately hard, fine grained earthenware that may be slightly translucent if thinly potted.  Feldspathic earthenware was made by many manufacturers and marketed under names including semi-porcelain, opaque porcelain, granite ware, stone china and iron-stone china.

Fine stoneware

A generic term for high quality stoneware (vitrified earthenware).  Examples include Wedgwood’s basalts, jasper, caneware etc.

Hard-paste porcelain

A porcellaneous (white, translucent) body manufactured from a mixture including china clay (kaolin) and china stone (petuntse) and covered in a glaze that is fused to the body in a high-temperature firing.

Ironstone china

A type of earthenware made from a paste containing powdered slag derived from the blast furnaces used to make iron. Vast quantities of durable ironstone china were exported from the Potteries to North America in the 19th and early 20th centuries.

Paste

The prepared mass of ingredients prior to its formation into a ceramic object. A paste is the result of mixing various ceramic materials according to a formula for, say, an earthenware body.

Porcelain

A hard translucent, white ceramic body manufactured originally from a mixture including china clay (kaolinite) and petuntse or china stone that, when fired, become vitreous and translucent. Originally discovered in China. A modern porcelain body would be manufactured from a mix of kaolinite, ball clay (added to increase plasticity), feldspar (the flux to help melt and fuse the paste) and silica to add body. See the definitions for ‘hard-paste’ and ‘soft-paste’ porcelains.

Porcellaneous

A body having the characteristics of porcelain i.e. whiteness, hardness and translucency.

Pottery

A non-specific term used for any ceramic body, but commonly used as a generic term for earthenware and stoneware which lack the high degree of translucence and whiteness associated with porcelain.

Raku

A low-temperature-fired earthenware where the body is composed of a prevously fired clay that has been broken up and pulverised. Of Japanerse origin.The word can refer to the finished ware or to the process of manufacture.

Soapstone porcelain

A variation of English soft paste porcelain.

Soft-paste porcelain

A porcellaneous (white, translucent) body produced from a range of materials (silica, gypsum etc) usually fused and ground and then mixed with china clay.  The soft-paste porcelains are generally fired at a lower temperature than hard-paste porcelain and the glaze does not fuse with the underlying body. Soft-paste porcelains are ‘warmer’ to touch compared to the ‘cold’ feel of hard-paste wares, and the surface glaze gives an impression of greater depth and gloss. Bone china is a soft-paste porcelain.

Stone china

An earthenware body containing powdered felspathic rock. An alternative term for feldspathic earthenware. Stone china was opaque, but the fine body enabled its manufacturers to use the term ‘china’.

Stoneware

A vitrified (non-porous) earthenware body manufactured from clay to which has been added materials such as sand or calcined flint which melt and re-crystallise at high temperatures, rendering the body non-porous and thus not requiring a covering glaze.  Stoneware is usually heavy, but need not be so, and is widely used in the manufacture of studio pottery.

Terracotta

An unglazed porous orange or red earthenware much used for garden and architectural pottery. The name is from the Italian ‘fired earth’.

Vitreous stoneware

A ceramic body rendered non-porous by vitrification at high temperature of ingredients contained within the paste. Stoneware is by definition vitreous so the term is somewhat redundant.