ABSORPTION: The assimilation of water by a ceramic body. It is used as a measure of the degree of vitrification.
ALUMINA BODY: A ceramic body produced by adding quantities of Alumina Oxide to the clay recipe. The result is a whiter, stronger ceramic body.
ALUMINA OXIDE: Aluminum Oxide a component found in all clays. When additional amounts of this oxide are added to a body or glaze formula it imparts greater strength and whiteness.
BALL CLAY: A fine grained sedimentary clay. Ball clay is a major component in many clay formulas, usually added to increase plasticity during the forming process.
BATCH: The materials that make up a ceramic body (or glaze) when they have been blended together in specific proportions.
BINDERS: Materials that are added to a glaze or clay recipe to increase glaze adherence or impart strength to a body during casting or pressing.
BISQUE: An unglazed clay body that has been fired once, to facilitate handling and to prepare it to receive glaze.
BLANK: An undecorated piece of dinnerware. This term usually applies when the item is scheduled for further processing.
BONE ASH: Calcium phosphate most often obtained through the calcining (subjection to extreme heat) of cattle bone.
BONE CHINA: A ceramic body first developed in Britain during the 18th century containing between 40% and 50% bone ash. This body is characterized by its strength, translucency and warm white color.
BURNISHING: A polishing process. Commonly used to remove oxidation from precious metal decorations after firing.
CASTING: A ceramic forming process. Items are formed by pouring slip into a plaster mold.
CRAZING: A defect in clayware glaze. A network of tiny cracks in glaze caused by the difference in the rate of contraction between the clay body and the glaze.
EMBOSSING: A raised or relief decoration on a dinnerware body. Generally produced in the mold, but sometimes formed separately and applied before firing.
FELDSPAR: A mineral aggregate used as a flux or glass forming agent in ceramic bodies and glazes.
FIRING: The controlled heat treatment of ceramic ware in a kiln or furnace to develop desired properties.
GLAZE: The glossy transparent or colored coating baked onto the surface of ceramic dinnerware. It reduces absorption, adds strength, and creates a pleasing decorative appearance.
GREENWARE: Ceramic items that have been formed but not fired.
HOLLOWARE: Ceramic, glass, or metal items capable of containing fluids, such as cups, bowls, or pitchers as opposed to "flatware" such as plates.
JIGGERING: A common method of forming ceramic dinnerware. In this process a spinning mold and/or template are used to form a clay slug.
KAOLIN: Also known as china clay. A very fine, white clay created by the decomposition of feldspar under the natural geologic forces of the earth.
KILN: The oven in which ceramic dinnerware is fired or baked.
LINING: A common dinnerware decorating process. Lines are applied concentrically to an item either by hand or by machine.
MOLD: Any form over or in which clay can be shaped.
OFFSET PRINTING: A decorating method in which a design is printed on the surface of a temporary carrier before transfer to the final item.
OXIDIZING ATMOSPHERE: An atmosphere inside a furnace or kiln that contains an oversupply of oxygen, in excess of that amount required for complete combustion.
PINMARKS: Small depressions (usually three) on the back of a glazed dinnerware item. These are caused by the support pins used during firing.
REDUCING ATMOSPHERE: An atmosphere inside a furnace or kiln with limited oxygen. This tends to remove oxygen from substances and materials fired or baked in it.
REFRACTORY: Inorganic, non-metallic, ceramic materials which retain their physical shape and chemical identity in the presence of extremely high temperatures.
SAGGER: A refractory box that contains dinnerware items during the firing process. It protects them from contamination and exposure to direct flame.
SCREEN PRINTING: A technique which involves the passage of pigment through a fabric to which a pattern stencil has been applied.
SINGLE FIRE: A firing cycle in which the normal bisque and glaze firings are combined.
SILICA: Silicon dioxide, the most common element in the earth's crust. Used as a filler in the composition of ceramic bodies.
SLIP: Clay blended with water until it achieves a liquid state.
THERMAL SHOCK: Stress created within a ceramic body caused by a rapid and dramatic change in temperature.
TRANSLUCENCE: The quality of some ceramic dinnerware bodies that allows them to transmit diffused light; semi-transparency.
TUNNEL KILN: A long tunnel-like oven in which dinnerware is fired while being carried through on flat cars.
VITRIFICATION: The progressive reduction or elimination of porosity in a ceramic body as a result of heat treatment.