Emery, a kind of metallic stone, found in several mines, but chiefly in those of iron, being a species of rich iron ore. It is usually of a, dusky, brownish red on the surface; but, when broken, is of a fine bright reddish iron-grey, spangled with glittering specks ; which are in a considerable degree impregnated with that metal. It is also sometimes red, when it usually contains veins of gold.
This stone, or ore, is divided into three sorts, namely, the Spanish, the red, and the common emery. The first is found in the gold mines of Peru, and is interspersed with small veins and specks of gold; whence it is conjectured to be a kind of ore of that rich metal, and is prohibited to be exported. From the experiments made by naturalists, it appears to be the metal called Platina, to which we refer. The red emery is discovered in cop-per-m nes, chiefly in Denmark and Sweden ; whence a small quantity is imported. The common emery is dug up in great abundance in the island of Guernsey. It is also obtained from some iron-mines in England, and is the only sort which is consumed in very considerable quantities by iocksmithsy glaziers, lapidaries, masons, cutlers, and others, who employ it for cutting and polishing glass, marble, and precious stones ; as well as for the polishing and burnishing of articles made of iron and steel. This species of emery is of a brownish colour, inclining to red; is extremely hard, and consequently very difficult to be reduced to powder ; an art which has been discovered in this country, and is effected by means of certain mills, invented for the purpose : when pulverized, it forms a considerable article of exportation. This native ore, when fused with lead or iron, possesses the property of hardening those metals. It is also said to increase the weight, and heighten the colour of gold. - It deserves no notice either as an-internal medicine, or as a dentrifice.