108 COPPER. Observations. r 1. Compact and Foliated Copper-glance are sometimes confounded with Grey Copper-ore, but may be readifv distinguished from it, by their being sectile, whereas grey copper-ore is brittle. The red colour and red coloured streak of Red Copper-ore, distinguish it at once from cop per-glance ; and Silver-gfonce or Sulphureted Silver-ore, although somewhat resembling the two first-mentioned subspecies of copper-glance in external aspect, yet may be readily distinguished from them by an obvious cha racter, viz. Its cutting readily into slices with a knife, whereas these ores separate into small grains when we’ attempt to cut therrt. '' ^ 2. The tarnished varieties of Compact and Foliated Copper-glance incline, and even sometimes pass, into Variegated Copper-ore. 3. The Frankenberg or Hessian corn-ears mentioned by authors, are sometimes aggregations of small crystals of copper-glance; sometimes, according to M. Monch true petrifactions of a phalaris, (Phalaris pulposa ?) com posed of copper-glance, white copper ore, and grey cop per-ore. They are sometimes invested with a thin cover of native silver. 4. It is rather a rare mineral, and the only country in which it has been met with in great quantity, is Siberia. Third