Gannister
A highly refractory siliceous rock, used very extensively in the several processes connected with the manufacture of steel and in the production of steel castings, but especially as a lining for the Bessemer converters. Ground quartz, sand, and fire-clay are mixed with this substance in varying proportions; but the silica, about 90 per cent, is cemented to some extent by the argillaceous matter it contains, making it in some instances sufficiently cohesive for ramming around a plug, and thus forming a solid lining in converters and steel-melting furnaces without any ad-mixture of alumina, etc., in which case the shrinkage is materially reduced and the original shape retained under very intense heat. See CONVERTER; REFRACTORY MATERIALS.