Carborundum

From Encyclopediak

Carborundum, a trade name given for an abrasive made in an electric furnace by smelting together sand, sawdust, coke and a little salt. It is used in its crushed state, like corundum and emery, and when ground into a fine powder it is employed to polish metals. It forms a valuable glaze for making fire bricks more durable, so they may stand greater heat. Its manufacture is covered by a patent and the electric smelter is at Niagara Falls. See ABRASIVES; EMERY.