tkON-MICA OR MICACEOUS IRON-GLANCE. 241 The fracture is perfect and curved foliated, with a single cleavage. The fragments are sometimes indeterminate angular, O sometimes tabular. The massive variety occurs in distinct concretions, "liich are large, coarse, small and fine granular. It is slightly translucent on the edges; but translucent ln thin plates. Its streak is chcrry-red. It is semi-hard, approaching to soft when it passes to re d scaly iron-ore. It is brittle. It is uncommonly easily frangible. It is heavy. Specific gravity, 4.500 to 5.070, Kirwan. Physical Characters. It slightly affects the magnet. Constituent Parts. According to Bucholz, this subspecies consists entirely Peroxide of Iron.—Gthlen's Journal, 2d series, b. iii. 104. *• Gcognostic Situation. It generally occurs in veins or in beds in newer primi- tlv e rocks, as mica-slate, and clay-slate; and in these re positories it is usually associated with red and brown Ir °nstone, and iron-pyrites, and sometimes with copper- P)’rites, sparry ironstone, calcareous-spar, fluor-spar, and quartz. Vol. III. Q Geographic