Tabular alumina is aluminum oxide that has been heated to temperatures above 1,650 °C (3,000 °F). Composed of tabletlike crystals, it has high heat capacity and thermal conductivity as well as exceptional strength and volume stability at high temperatures. For these reasons, a major use of tabular alumina is in the production of high-quality refractories, the materials used for lining industrial furnaces. High-alumina refractories are used in the metal and glass industries in boiler installations, in large furnaces and kilns for smelting metals and firing glass, pottery and porcelain, and in the manufacture of building bricks.