The Probert Encyclopaedia of Rocks & Minerals

FIRE-CLAY

Fire-clay is a compact kind of clay, consisting chiefly of silica and alumina, capable of sustaining intense heat, and used in making fire-bricks (for furnaces), gas-retorts, crucibles, etc. Fire-clay is found in various regions, but the most highly esteemed is that of Stourbridge, which resists very high temperatures. Fire-clay generally belongs to the coal formation, forming a stratum immediately below each seam of coal.
Research Fire-Clay