LIGHT RED SILVER-ORE. 83 lateral planes of the one are set obliquely on the lateral planes of the other, and very flatly acu minated on the extremities with three planes, which are set on the obtuse lateral edges. 4. Very acute six-sided pyramid, very flatly acumi nated with six planes, which are set on the late ral planes. 5. Double six-sided pyramid, less acute than the pre ceding, in which the acute lateral edges are trun cated. 6. Equiangular double six-sided pyramid, acuminated with six planes, which are set on the lateral planes, and the summit truncated. 7. Also in acicular crystals. The crystals are seldom middle-sized, usually small, and very small, and occur in druses. The surface of the crystals is usually smodth, some times streaked; the streaks being longitudinal in the prisms, but oblique in the pyramids, and sometimes drusy. Externally the lustre is splendent. Internally it alternates from splendent to glistening, and has usually an adamantine lustre ; the varieties that incline to the foregoing subspecies have a semi-metallic lustre. The fracture is usually imperfect and small conchoidal, which sometimes passes into coarse and small grained uneven, sometimes into imperfect foliated, which latter has the greatest degree of lustre, and occurs only in the crystallised varieties. The fragments are rather sharp-edged. The massive varieties are generally translucent on the edges; the crystallised usually transparent. V 2 Tfc