344. AZURESTONE FAMILY. held between the eye and the light, all the colours ap pear somewhat muddy. It occurs disseminated, in angular imbedded grains, and crystallised in rhomboidal dodecahedrons like gar- net. Internally it is shirting and vitreous. The fracture is imperfect conchoidal, passing into splin tery, or inclining to imperfect foliated. The fragments are angular and sharp-edged. It is semi-transparent and transparent. It scratches glass; also felspar and quartz very feebly. It is easily frangible. Specific gravity, 3.333, Gismondi. 3.100, Neergaard. Chemical Characters. It is infusible without addition before the blowpipe, and its colour remains unaltered ; but with borax forms yellowish-green glass. With acids it forms a translucent jelly. Constituent Parts. Silica, 30.0 Alumina, 15.0 Sulphate of Lime, 20.5 Lime, - 5.0 Potash, 11.0 Iron, 1.0 Trace of Sulphureted Hy drogen. Loss, 17.5 100 Vauquelin. The