64 CHRYSOLITE FAMILY. The broader lateral planes are deeply longitudinally streaked; but the smaller lateral planes, and the acumi nating planes, are smooth. The crystals are middle-sized and small; occur rest ing on one another, intersecting one another, and collect ed into scopiform groups. Externally it is shining and glistening, and pearly; internally it is shining and vitreous. The fracture is foliated, with a fourfold cleavage : of these two are parallel with the truncations on the lateral edges, a third with the smaller lateral planes, and the fourth with the broader lateral planes; some varieties incline to radiated. The cross fracture is imperfect and small conchoidal. The fragments are splintery. It occurs in thin and very thin lamellar distinct con cretions, which sometimes approach to columnar. It is translucent. It scratches fluor-spar, but hardly glass. It is easily frangible. Specific gravity, 3.310, Hauy. Chemical Character. It melts with difficulty before the blowpipe. Constituent Parts. Silica, Magnesia, Lime, Iron and Manganese, 57.50 18.25 16.50 6.00 Laugicr, Geognqslie