Ceramic glaze
A glass-forming coating fused to a ceramic surface during firing. It can add color, texture, and protection while reducing porosity.
Silica: Silicon dioxide, a compound found in minerals and used as the principal glass former in many glazes. Silica builds the glassy network that gives fired glaze its continuous surface.
Ceramic: An inorganic, nonmetallic material hardened by heat. Glaze is a coating applied to a ceramic object and fused during firing.
Earthenware: A porous ceramic fired at relatively low temperatures, often made watertight with glaze. Glaze can seal earthenware that would otherwise absorb liquids.
Underglaze: A ceramic colorant applied beneath a transparent or translucent glaze. Underglaze supplies decoration below the fused surface rather than forming the surface itself.
Flux (ceramics): A glaze ingredient that lowers the temperature at which silica melts and forms glass. Fluxes make glaze mature at temperatures suitable for the clay body and kiln.
Clay body: The shaped ceramic material beneath a surface coating, made from clay and other mineral ingredients. The body supports the glaze and affects how the two materials bond.
Porcelain: A dense, vitrified ceramic known for its pale body and translucency in thin sections. Porcelain is often glazed to add a compatible surface and visual finish.
Engobe: A liquid clay coating applied to ceramic ware, often to change its color or surface. Unlike glaze, engobe is primarily clay and does not form a glassy coating.
Alumina: Aluminum oxide, a ceramic material that increases the viscosity and durability of many glazes. Alumina helps keep molten glaze from running off a vessel.
Feldspar: A group of rock-forming minerals commonly used as a source of silica, alumina, and fluxes in ceramic recipes. Feldspars supply several ingredients that help a glaze form glass in a kiln.