List of pottery terms
Encyclopedia
Historically the production of 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...

 has been a characteristic of human activity in most areas of the world. Over time, each culture has established terms which define tools, ingredients and production techniques. Terms currently in use may be derived from a variety of pottery traditions.

List of pottery and ceramic terms

NOTE: Where terms are described in detail in other Wikipedia articles, the term may not be defined in this list. A link to the main article is given in these cases. Some terms may be defined in this list, but a link to a Wikipedia article may give more detail and context for the use of the term. Links to appropriate short definitions in Wiktionary are noted as "(W)" for more information.

A

  • Absorbency. The ability of a material (clay, etc.) to soak up water.

  • Alumina. A major ingredient in all clays and glazes which imparts greater strength and higher firing temperatures.

B

  • 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...

    .
    A secondary clay moved from the parent rock, ball clay is often mixed with other clays and minerals, organic matter are frequently present. Ball clays commonly exhibit high plasticity and high dry strength.(W)

  • Band. are lines marked around circular ceramic utensils, plates, jars or lids using any method of decoration which can be applied at all stages of manufacture. Banding is the action of marking a band.

  • Bat. Or "batt." Less commonly also known as a "batterboard", thin slab of wood, plaster, or plastic used to support pottery forms during throwing, attached to the head of the potter's wheel by clay body or "bat pins".

  • Bentonite
    Bentonite
    Bentonite is an absorbent aluminium phyllosilicate, essentially impure clay consisting mostly of montmorillonite. There are different types of bentonite, each named after the respective dominant element, such as potassium , sodium , calcium , and aluminum . Experts debate a number of nomenclatorial...

    . An extremely plastic clay which can be added in small quantities to short clay to make it more plastic.

  • Bisque
    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 Biscuit. Pottery that has been fired but not yet glazed. (W)

  • Bisque Fire. Preliminary firing prior to glazing and subsequent firing at a higher temperature.

  • Bloating. The permanent swelling of a ceramic article during firing caused by the evolution of gases.

  • Blunging. The wet process of blending, or suspending ceramic raw materials in liquid by agitation.

  • Body. The structural portion of a ceramic article, or the material or mixture from which it is made.

  • Bone Ash. Calcined animal bone used in the production of 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...

    . (W)

  • 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...

    .
    Vitreous, translucent pottery made from a body of the following approximate composition: 45-50% calcined bone, 20-25% kaolin. 25-30% china stone. (W)

  • Bone-dry The final stage of greenware dried to a completely dry state and ready to be fired. In this stage, the clay is very fragile, non-plastic and porous.

C

  • Candling. Usually done anywhere from 3 to 12 hours before a firing, candling is the initial lighting of a kiln to take any chemically-bound water out of the clay body. Its purpose is to prevent pieces from exploding during firing.

  • Carbonizing The permanent staining of clay by the introduction of carbon particles during firing.

  • Casting, slip casting
    Slipcasting
    Slipcasting is a technique for the mass-production of pottery, especially for shapes not easily made on a wheel. A liquid clay body slip is poured into plaster moulds and allowed to form a layer, the cast, on the inside cavity of the mould...

    (W)

  • Celadon
    Celadon
    Celadon is a term for ceramics denoting both a type of glaze and a ware of a specific color, also called celadon. This type of ware was invented in ancient China, such as in the Zhejiang province...

    Stoneware glazes containing iron which produce green, gray and gray-blue colors in reduction firing.

  • 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...

    (W)

  • Cheese hard Another term for leather-hard.

  • China A term often referring to Porcelain ware. Used more generically for any ceramic tableware. (W)

  • China Clay Refers to Kaolin, which is the primary clay used for producing Porcelain.

  • Chamotte (Grog) A ceramic material formed by the high temperature firing of a refractory clay, after which it is crushed and graded to size. Used as the a non-plastic component of some clay bodies. (W)

  • Clay
    Clay
    Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...

    A group of hydrous aluminium phyllosilicate minerals. Often also used to refer to the clay body, which sometimes may only contain small amounts of clay
    Clay
    Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...

     minerals. (W)


  • Clay body The material used to form the body of a piece of pottery. Thus a potter might order such an amount of earthenware body, stoneware body or porcelain body from a supplier of ceramic materials.

  • Coiling A hand method of forming pottery by building up the walls with coils of ropelike roles of clay.

  • Cone, See pyrometric cone
    Pyrometric cone
    Pyrometric cones are pyrometric devices that are used to gauge heatwork during the firing of ceramic materials. The cones, often used in sets of three as shown in the illustration, are positioned in a kiln with the wares to be fired and provide a visual indication of when the wares have reached a...

    .

  • Crackle glaze A glaze intentionally containing minute cracks in the surface.

  • Crawling. A parting and contraction of the glaze on the surface of ceramic ware during drying or firing, resulting in unglazed areas bordered by coalesced glaze. (W)

  • Crazing
    Crazing
    Crazing is a network of fine cracks on the surface of a material, for example in a glaze layer.Crazing is a phenomenon that frequently precedes fracture in some glassy thermoplastic polymers. Crazing occurs in regions of high hydrostatic tension, or in regions of very localized yielding, which...

    .
    A glaze fault characterised by the cracking of fired glazes and due to high tensile stresses. (W)

  • Crock
    Crock
    A crock is a botched attempt or design to achieve something, particularly in engineering. An automobile with intentionally designed square wheels would be a crock. Crock itself is a slang word, meaning something which is broken down, worn out or nonsense....

    .
    synonym of pot. (W)

  • Crocker. synonym of a potter, one who creates pottery (archaic). (W)

  • Crockery. synonym of pottery. (W)

  • Crystal glaze Glazes characterized by crystalline clusters of various shapes and colors embedded in a more uniforma and opaque glaze

  • china clay See Kaolin

D

  • Deairing. The removal of entrapped air from a mass or slurry, often by the application of a vacuum. (W)

  • Deflocculate. To separate agglomerates in a slurry by chemical means, and so decrease viscosity. (W)

  • Delft ware A light-colored pottery body covered with a tin glaze with overglaze decorations in cobalt on the unfired glaze in attempt by the Dutch to imitate Chinese blue and white porcelain.

  • Dipping Glazing pottery by immersing itg in a large pan or vat of glaze.

  • Dunt. A crack caused by thermal shock, especially if ware cooled too rapidly after it has been fired. (W)

E

  • Earthenware
    Earthenware
    Earthenware is a common ceramic material, which is used extensively for 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, 28% kaolin, 32% quartz, and 15%...

    . A pottery created by low temperature firing. (W)

  • Enamel
    Vitreous enamel
    Vitreous enamel, also porcelain enamel in U.S. English, is a material made by fusing powdered glass to a substrate by firing, usually between 750 and 850 °C...

    (W) Coloured, glass-like decoration applied to ceramic wares. Also called on-glaze decoration. Often made by mixing metal oxides with a lead-based flux. Enamels are usually fired to temperatures in the range of about 700 to 800 degrees Celsius.

  • Eutectic. An invariant point on an equilibrium diagram. A mixture of two substances which has the lowest melting point in the whole series of possible compositions. (W)

  • Engobe. A slip coating applied to a ceramic body for imparting colour, opacity or other characteristics. It may subsequently be covered with a glaze. (W)

F

  • 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...

    A form of tin-glazed earthenware (W)

  • Fat clay A very plastic form of clay such as ball clay

  • Fettling. The removal, in the unfired state of excess body left in the shaping of pottery-ware at such places as seams and edges. (W)

  • Fire clay
    Fire clay
    Fire clay is a term applied to a range of refractory clays used in the manufacture of ceramics, especially fire brick.High grade fire clays can withstand temperatures of 1775°C , but to be referred to as a "fire clay" the material must withstand a minimum temperature of 1515°C...

     A highly heat resistant form of clay which can be combined with other clays to increase the firing temperature.

  • firing. The process of heating clay pottery in a kiln to bring the glaze or clay to maturity'

  • Flatware (W)

  • Flux
    Flux
    In the various subfields of physics, there exist two common usages of the term flux, both with rigorous mathematical frameworks.* In the study of transport phenomena , flux is defined as flow per unit area, where flow is the movement of some quantity per time...

    .
    substance that promotes fusion in a given mixture of raw materials. (W)

  • Frit. A product made by quenching and breaking up a glass of a specific composition. Common uses include as components of a glaze or enamel. (W)

  • Frit china A glossy, partly translucent chinaware produced by adding a glass frit to the body.

G

  • Potter's gauge
    Pottery gauge
    A pottery gauge is one of various tools used in pottery to ensure that pots thrown on a potter's wheel are uniform in size or shape. Some pottery gauges simply ensure that the height and diameter are consistent, others are templates or shapers....

    .
    A tool used to ensure that thrown pots are of uniform size or shape.

  • Glaze. A coating that has been matured to the glassy state on a formed ceramic article, or the material or mixture from which the coating is made. (W)

  • Glaze firing A firing cycle in a kiln to the temperature at which the glaze materials will melt to form a glasslike surface coating.

  • Glost fire. A glaze firing which is at a lower temperature than the bisque fire.

  • Greenware. Unfired clay articles. There are a series of drying stages greenware goes through: wet, damp, soft leather-hard, leather-hard, stiff leather-hard, dry, and bone dry.

  • Grog. See chamotte, above. (W)

  • Gum arabic
    Gum arabic
    220px|thumb|right|Acacia gumGum arabic, also known as acacia gum, chaar gund, char goond, or meska, is a natural gum made of hardened sap taken from two species of the acacia tree; Acacia senegal and Acacia seyal...

    Natural gums used as binders to enable the glaze to adhere better to the body.

H

  • Hard-paste porcelain
    Hard-paste porcelain
    Hard-paste porcelain is a ceramic material that was originally made from a compound of the feldspathic rock petuntse and kaolin fired at very high temperature. It was first made in China around the 9th century....

    , True porcelain which is fired at or above 2420 degrees Fahrenheit.

  • Hollowware. (W)

I

  • Iron oxide
    Iron oxide
    Iron oxides are chemical compounds composed of iron and oxygen. All together, there are sixteen known iron oxides and oxyhydroxides.Iron oxides and oxide-hydroxides are widespread in nature, play an important role in many geological and biological processes, and are widely utilized by humans, e.g.,...

    . A common flux found in glazes, slips, and in many body clays that generally gives a redish color.

J

  • Jigger. A machine for the shaping of clay body into flatware by the differential rotation of a profile tool and mould. Also the process. (W)

  • Jolley. To shape hollowware by the same process as jigger. (W)

K

  • Kaolin. Otherwise known as china clay, white or off-white firing kaolinitic. Used to make porcelain(W)

  • Kidney A kidney-shaped tool mad of flexible steel for finishing thrown pots or made of stiff rubber for pressing and smoothing clay in a mold.

  • Kiln
    Kiln
    A kiln is a thermally insulated chamber, or oven, in which a controlled temperature regime is produced. Uses include the hardening, burning or drying of materials...

    A furnace made of refractory clay materials for firing pottery.

  • Kiln furniture Refractory shelves and posts upon which ceramic ware is placed while being fired in the kiln.

  • Kiln spurs
    Kiln spurs
    Kiln spurs are supports, often in the shape of a tripod, used to maintain the shape and separate pieces of ceramic during the firing process....

    .
    Supports, often in the shape of a tripod, used to maintain the shape and separate pieces of 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...

     during the firing process.

  • Kneading is a step in preparing clay for shaping. It involves manipulating the clay in a fashion somewhat like Kneading
    Kneading
    Kneading is a process in the making of bread or pasta dough, used to mix together the ingredients and add strength to the final product. Its importance lies in the mixing of flour with water. When these two ingredients are combined and kneaded, the gliadin and glutenin proteins in the flour expand...

     dough for bread. It ensures the even distribution of moisture in the body.

L

  • Leather-hard
    Leather-hard
    Leather-hard is the condition of a clay or clay body when it has been partially dried to the point where all shrinkage has been completed. At this stage the clay object has approximately 15% moisture content. The clay is still visibly damp but has dried enough to be able to be handled without...

    or Cheese hard The condition of a clay or clay body when it has been partially dried to the point where all shrinkage has been completed. (W)

  • Limestone
    Limestone
    Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....

    A major flux for whitening in medium- and high-fire temperature ranges.

  • Luster A type of decoration used in Egypt and Persia which leaves a thin layer of metal on the decorated portions of pottery.

  • Luting A method of joining together two pieces of dry or leather-hard clay with a slip.

M

  • Majolica
    Majolica
    Majolica, an English version of the Italian word maiolica, is a term covering a wide variety of European tin-glazed pottery, typically brightly painted over an opaque white background glaze, with an earthenware body....

    or maiolica Earthenware developed in Majorca which is Tin-glazed and overpainted with oxides. Similar pottery is known in France as Faience and Englad as Deftware.

  • Mat glaze A dull-surfaced glaze with no gloss.

  • Maturing temperature The temperature at which a glaze exhibits it best qualities.

  • Maturity. The combined effects of firing time and firing temperature on ceramic wares in a kiln. Within limits, wares fired at low temperatures for extended periods may develop a degree of maturity similar to that achieved by applying higher firing temperatures for shorter periods. (W)

  • Modulus of Rupture.
    Flexural strength
    Flexural strength, also known as modulus of rupture, bend strength, or fracture strength, a mechanical parameter for brittle material, is defined as a material's ability to resist deformation under load...

    The maximum transverse breaking stress applied under specified conditions, that a material will withstand before fracture. It is used as a common quality control test used for both ceramic rawmaterials and ceramic bodies. (W)

  • Muffle kiln. A kiln used for firing enamelled decoration, constructed so as to protect wares from direct flame and from smoke, soot, ash and other contaminants.

  • Mullite
    Mullite
    Mullite or porcelainite is a rare silicate mineral of post-clay genesis. It can form two stoichiometric forms 3Al2O32SiO2 or 2Al2O3 SiO2. Unusually, mullite has no charge balancing cations present...

    Interlocking needlelike crystals of aluminum silicate responsible for toughness and hardness of ttoneware and porcelain which form in high-temperature bodies.

O

  • Once-fired, green-fired (W)

  • Opacifier
    Opacifier
    An opacifier is a substance added to a material in order to make the ensuing system opaque. An example of a chemical opacifier is tin dioxide , which is used to opacify ceramic glazes and milk glass; bone ash is also used....

    A glaze that is opaque and hence covers the color of the clay body

  • Orton cones
    Orton Ceramic Foundation
    The roots of the Orton Ceramic Foundation date back to the establishment of the "Standard Pyrometric Cone Company" in 1896 by Dr. Edward J. Orton, Jr.. Dr. Orton was a pioneer in developing and applying scientific principles to ceramic manufacturing...

    One set of pyrometric cones which differs from the Seger cones in the temperatures associated with the cone numbers.

  • Overglaze (W) See Enamel, above.

  • Oxidation (W)

  • Oxidizing firing A firing in a kiln that retains an oxygen environment.

P

  • Paper Clay Adding reconstituted paper pulp to ordinary plastic clay in proportions up to 50% of the toal which gives a material of great plasticcity giving an advantage to hand builders and sculptors.

  • Pinholes. Faults in the surface of a ceramic body or glaze which resemble pin pricks. (W)

  • Plasticity is the quality of clay that slloed it to be manipuated and still maintain its shape without cracking.

  • 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...

    .
    A vitreous ceramic material. Traditionally considered to be white and if, of thin section, translucent. (W)

  • Potsherd. (W)

  • Potter. A person who makes pots or other ceramic art and wares. (W)

  • Potter's clay. The clay used by the potter (W)

  • (Potter's) Wheel
    Potter's wheel
    In pottery, a potter's wheel is a machine used in asma of round ceramic ware. The wheel may also be used during process of trimming the excess body from dried ware and for applying incised decoration or rings of color...

    .

  • 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...

    .
    All fired ceramic wares or materials which, when shaped, contain a significant amount of clay. Exceptions are those used for technical, structural or refractory applications. Pottery is also: (1) the art and wares made by potters; (2) a ceramic material (3) a place where pottery wares are made; and (4) the business of the potter. (W)
Published definitions of Pottery include:
-- "All fired ceramic wares that contain clay when formed, except technical, structural, and refractory products."
-- "China, earthenware and any article made from clay or from a mixture containing clay and other materials."
-- "A class of ceramic artifacts in which clay is formed into containers by hand or in molds or with a potter's wheel, often decorated, and fired"
-- "The term pottery includes many varieties of ware from the crudest vessels of prehistoric times to the most beautiful decorated porcelains, stoneware and earthenware; it also includes many articles such as large grain-jars used in ancient times for storing corn and other dry materials, wine-jars and modern sanitaryware and the large tanks for containing corrosive acids. Many kinds of earthenware, stoneware and porcelains are used for scientific and experimental purposes as well as electrical apparatus (insulators, switch-bases, sparking plugs and bases or frames for electrical heating appliances)."

  • Pug. Also pug mill. A machine for consolidating plastic clay or body into a firm column. It consists of a barrel which tapers at one end to a die, through which the clay or body is forced by knives mounted on a shaft which rotates centrally to the barrel. A vacuum system may be installed to de-ier the clay or clay body. (W)

  • Pyrometer a temperatue indicator linked to a kiln via a thermocoupler.

  • Pyrometric cone
    Pyrometric cone
    Pyrometric cones are pyrometric devices that are used to gauge heatwork during the firing of ceramic materials. The cones, often used in sets of three as shown in the illustration, are positioned in a kiln with the wares to be fired and provide a visual indication of when the wares have reached a...

    s.
    (W)

Q

  • 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,...

    Flint or silica.

  • Quartz inversion
    Quartz inversion
    The room-temperature form of quartz, α-quartz, undergoes a reversible change in crystal structure at 573 °C to form β-quartz. This phenomenon is called an inversion, and for the α to β quartz inversion is accompanied by a linear expansion of 0.45 %. This inversion can lead to cracking of...

    Strctural changes to quartz during firing is reversed for free quartz.

R

  • Roller-head machine(W) Used in mass production of pottery, a rotary shaping tool that replaces jigger and jolley to shape wares.

  • Raw, is unfired clay

  • Raw glazing. refers to applying a glaze to an unfired ware and firing both in a "Once-firing".

  • Reduction. Firing in an oxygen starved environment.

  • Refactory refers to heat resistant or clay that is fired at a high tempereture.

S

  • Saggar. A lidded or covered ceramic box used to protect wares from direct flame, smoke, fuel-ash or cinders during firing.(W)

  • Scrafito. This is a decorating technique where a slip is applied to a leather-hard piece of clay and left to dry. Once the slip is dry a host of different tools are used to carve into the clay to remove the slip and leave an embedded decoration behind.

  • Single-fired see once-fired

  • Sintering is the process caused by kiln firing which solidifies the clay but does not lead to vitrification. This occurs at low temperatures as in low-fired earthenware.

  • Slip A suspension of clay, clay body or glaze in water.(W)

  • Soaking is The time during the firing cycle when a steady temperature is maintained to allow optimal maturation of the glazes.

  • Stoneware. A vitreous or semivitreous ceramic material. Traditionally made primarily from nonrefractory fire clay.(W)

  • Seger cone see Pyrometric cone

T

  • Terracotta (W)

  • Throwing The term used when referring to forming or shaping on a potter's wheel. (W)

U

  • Underglaze
    Underglaze
    Underglaze is a method of decorating ceramic articles, the decoration is applied to the surface before it is glazed. Because the glaze will subsequently cover it such decoration is completely durable, but because the subsequent glost firing is at a higher temperature than used in on-glaze...

    A color applied to a bisque-fired pottery and covered with a glaze. (W)

V

  • Vitreous. Pertaining to the hard, glassy, and nonabsorbent quality of a fired body or glaze.

  • Vitrification Process by which clay materials bond tro become dense, nonabsorbent, and glassified after firing.

W

  • Water Absorption. The mass of water absorbed by a porous ceramic material, under specified conditions, expressed as a percentage of the mass of the dry material. It is used as a common quality control test used for both ceramic raw materials and ceramic bodies. (W)

  • Wedging. A procedure for preparing clay or a clay body by hand: the lump of clay is repeatedly thrown down on a work bench; between each operation the lump is turned and sometimes cut through and rejoined in a different orientation. The object is to disperse the water more uniformly, to remove lamination and to remove air. (W)

External links

  • ASTM Standard C242-00. Standard Terminology of Ceramic Whitewares and Related Products.
  • Dictionary of Ceramics 3rd edition. Dodd A., Murfin D. The Instiutue of Materials. 1994.
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