AU'GITE (front Gr. auge, brilliancy), or (from Gr. pair, fire, and xenos, a guest), a mineral very nearly allied to hornblende (q.v.), which has, indeed, by sonic mineralogists been regarded as a variety of it, although the distinction between them is undeniably important, as characterizing two distinct series of igneous rocks. A. con sists of 41' to 56 per cent of silica, 20 to 25 per cent of lime, and 12 to 19 per cent of magnesia, the maguesia sometimes giving place in whole or in part to protoxide of iron, and some varieties containing a little alumina, or a little protoxide of manganese. Its specific gravity is 3.195 to 3.525. It is little affected by acids, or not at all. It is usually of a greenish color, often nearly black. It crystallizes in six or eb'ht-sided prisms vari ously modified; it often occurs in crystals, sometimes imbedded, often in grains or scales. It is an essential component of many igneous rocks, particularly of basalt (q.v.), dolerite, and A. porphyry (see Poarnvitv), from which chiefly it derives its importance as a mineral species. A. rock, consisting essentially of A. alone, occurs in the Pyrenees. A. is a common mineral in the trap-rocks of Britain and other countries. It is rarely associated with quartz. in which respect it differs from hornblende, but very often with
labradorite, olivine, and leucite. Fluorine, which is generally present in small quantity in hornblende, has never been detected in A. The form of the crystals is also different in the two minerals, as well as their cleavage; but prof. Gustav Rose of Berlin has endeavored to show that the difference between A. and hornblende arises only from the different circumstances in which crystallization has taken place, and that A. is the pro duction of a comparatively rapid, and hornblende of a comparatively slow cooling. Ile regards some of the varieties as intermediate. this views have been supported by experi ments. and by a comparison of A. with certain crystalline substances occurring among the scoriae of foundries.Biiqt.vide, sahlite, and roccolite are varieties of A.Diallage (q.v.) and hypersthene (q.v.) arc very nearly allied to it.
a co. in w. Ohio. intersected by the Dayton and Michigan and the Lake Eric and Louisville railroads; 339 sq.m.; pop. '80. 25,465. The Miami canal passes through, and it is drained by A. river. Surface level, well wooded, and soil fer tile. Co. scat. Wapakoneta.