Emery, a fine grained, black sandstone. Its color is due to the presence of iron. In use it may be cut into the shape of a grindstone and caused to rotate on an axis; but it is so difficult to work that it is really easier to pound the stone into a powder and build it up into the required shape again with cement. Rubber and copper are frequently added to the composition to diminish danger from breaking. The emery paper on sale at hardware stores consists of paper coated with glue and dusted with emery powder. Its principal use is in smoothing metal and wood. Emery cloth is prepared in the same way. It is used chiefly for polishing metals. Emery is found in Massachusetts, Georgia, and North Carolina; but the world's chief supply is obtained from Asia Minor and the Grecian Archipelago. Emery ranks next to the diamond in hardness. It will cut glass or any other material save the diamond. See CORUNDUM; ALUMINUM; SAPPHIRE.