EMERY.
Emeri ; Emeril, . . FR. Nashdak, . . . . Rus. Sxnirgel, . . . . . GER. Esmeril, . . . . SP. Smeregio ; Srnerglio, IT. Zimpara, . . . TURK.
LAT This substance is greatly used in the arts for grinding an.d polishing hard minerals and metals. Corundum, emerald, ruby, topaz, sapphire, and emery are only surpassed in hardness by the diamond. Emery is regarded as granular or amorphous corundum, coloured with iron, and is not known to occur in India, where corundum and garnets are used by the people in its place. It was, however, sent to the Exhibition of 1862, from Monghir ; and Callastry, near Madras, is also named as a site, also Ongole. In the mixed corundums of Greece and Turkey the iron seems equally diffused through the mass, imparting to it a bluish-grey colour ; but in specimens which reached the lsladras Museum from Southern Baia, the corundum and ore of iron, though occurring together, are not mixed, but remain apart, segA g,ated, the corundum forming one side of a, mineral, and the oxide of iron, in a -lump or lumps, on the. other side ; and all such masses ' are magnette,.and possess polarity. In the arts, that of Naxos is preferred, as it is more uniform in its quality than that from Pulah and Guinuch. That from Naxos is of a dark grey colour, with a mottled surface, and with small points of a mica ceous mineral disseminated in the mass. It fre
quently contains bluish specks or streaks, which are easily recognised as being pure corundum. When reduced to powder, it varies in colour from dark grey to black, but the colour of its powder affords no indication of its commercial value. The powder of emery examined under the micro scope shows the distinct existence of the two minerals, corundum and oxide of iron. The specific gravity of emery is about 4, but its.hard ness is its most important property in its applica tion to the arts. The only difference in corun dum seems to be the absence of oxide of iron. There could be no difficulty in preparing coruudum powders of the requisite degrees of fineness. The selling price of corundum in London has ranged from .£10 to 125 a ton. There seems no reason why the picked corundums should sell for less than the finest emeries ; and Captain Newbold mentions that the corundums near Gram, when sorted into the three sorts known in commerce, viz. the red, the whites, and the scraps, of these two are sold to the Arab merchants at Mangalore and Tellicherry at prices from 12 to 15 or 30 rupees the candy, equal to £1, £6, and 112 a ton.—Madras Museum Report. See Corundum.