COPPER-MICA. 185 It is sectile. It is gather brittle. Specific gravity, 2.5488. Chemical Characters. It decrepitates before the blowpipe; and passes, first to the state of a black spongy scoria, after which it melts into a black globule, of a slightly vitreous appearance. Constituent Parts. Oxide of Copper, Arsenic Acid, Water, Mines, N. 55. p. 562 39 58 43 21 17 21 99 100 i. des Chencvix, Phil. Tr. .562. for 1801, p. 201. Geognostic and Geographic Situations. It has been hitherto found only in veins in the copper- mines in Cornwall, where it is accompanied with red cop- per-ore, copper-pyrites, copper-glance or vitreous copper- ore, variegated copper-ore, copper-black or black oxide of copper, compact atid fibrous malachite, ironshot cop per-green, azure copper-ore, indurated tile-ore, oliven- ore, and brown iron-ochre. 21. Lenticular