Copper

Cu. At. wt. 63.09. One of the few metals known to the ancients. From the mines of Cyprus it got its Latin name, cuprum, and from this the English name is derived. Copper is present in a large number of minerals, ten of which are sufficiently rich and abundant to be valuable as ores; viz., wife' native copper, chalcocite, bornite, chalcopyrite, tetrahedrite, cuprite, melaconite, chrysocolla, malachite and azurite. Of these the most important are native copper and chalcopyrite, the latter being of world-wide distribution. Copper ores are not restricted to any one geological formation nor to any one mode of occurrence. Some of the more productive districts have been in s.w. England, Spain, Chili, and, in the U. S., Mich., Montana, and Arizona. Copper is soluble in the common acids. It forms two cla es of salts: cuprous, in which it is univalent, and cupric, in which it is bivalent.