Rich golden-brown stoneware clay, no longer being mined. See Lizella clay.

A well known Kentucky ball clay.

In glaze formulation, a material that produces inert inclusions or minute crystals in glaze, causing it to become opaque. Most common are tin oxide and zirconium silicate.

In a gas or oil burner, the restricted opening through which a jet of fuel emerges.

The escape of gases from clay and glazes during firing. Carbonates, sulfates, nitrates, organic contaminants, and chemically combined water volatize between 600 and 1200° F. Other compounds, especially fluxes, volatize later during glaze-melt. See carbon coring, oxidation cleanup, water-smoking stage.

Any surface decoration applied over the glaze surface, either as an oxide wash applied over raw glaze surface before glaze-firing, or as a lower-temperature medium fired onto a previously higher-fired glaze surface, as in china paints and lusters.

In spraying glazes or other mediums, the small droplets and/or dust that do not settle on the object being sprayed. An adequate spray booth is essential in order to exhaust all overspray.

Potash feldspar no longer mined. Substitute Custer or G-200.

  Any chemical reaction in which atoms or molecules combine with oxygen atoms. The combustion of fuel is an oxidation reaction.

After glaze reduction, a short period of oxidation to allow out gassing to stop and glazes to heal.

Any kiln atmosphere with an abundance of oxygen to combust the fuel and oxidize the ceramic materials. Includes all electric firings and any gas firing with adequate air to insure complete combustion of the fuel close to the burner.

A molecule combining any element with oxygen.

A mixture of coloring oxide and water, sometimes including a little flux, used as an overall patina (often on unglazed work) or for over glaze brushwork. See patina.

To subject a material to a high-oxygen atmosphere, encouraging oxidation reactions.