Emery

(ém'ür-e.) [From Cape Emeri, Isle of Naxos.] (Min.) A compact variety of Corundum, very generally regarded as a kind of iron ore. It is of a blackish -gray color, and so very hard as to scratch topaz. It consists of alumina, silica, and iron; and is used in the form of a powder for polishing hard minerals and metals. The lapidaries cut ordinary gems by sprinkling their wheels with the moistened powder ofE.; but it will produce no effect on the diamond. [s. 328]