silica refractory
121dinas brick — ˈdēnəs noun Usage: usually capitalized D Etymology: after Craig y Dinas, Wales : a refractory silica brick made from an impure sandstone containing lime and clay and formerly used in furnace crowns …
122thorium oxide — noun or thorium dioxide : a refractory crystalline compund ThO2 obtained usually as a dense white powder by igniting thorium nitrate and used chiefly in incandescent gas mantles, in crucibles and refractories, in silica free optical glass, and in …
