COMMON IRON-FYRITES. 207 The fracture is coarse, small and fine-grained uneven *. The fragments are indeterminate angular, and rather sharp-edged. It sometimes occurs in fine granular distinct concre tions. It is hard. It is brittle. It is rather difficultly frangible. When rubbed, or struck with steel, it emits a strong sulphureous smell. Specific gravity,— Dodecahedral pyrites, Pyrites in smooth-planed cubes, Pyrites from Frey berg, Cornwall, Cubic pyrites, Id. 4.830, 4.831, 4.682, 4.789, 4.600, | 4.7016, j Hatchett. Id. Gellerl. Kirwan. Brisson. Chemical Characters. Before the blowpipe it emits a strong sulphureous odour, and burns with a {bluish flame. It. afterwards changes into a brownish-coloured globule, which is at tractable by the magnet, and by continuance of the heat, passes into a blackish slag, which communicates a dirty- green colour to borax. Constituent. * Hausmann mentions a variety of common iron-pyrites with perfect, 'arge, and flat conchoidal fracture, and nearly splendent lustre, and hence proposes to subdivide this subspecies into two kinds, viz. Uneven and CW- elteidal common iron-pyrites,—Yid. Leonhard's Taschenbuoh, b. tiii*