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were wrought quite extensively before the war. Four or five of them have been recently re-opened, and put in operation on a large scale. It occurs in rocks of both Lauren- tian and Huronian age, chiefly in a gangue of quartz, but also in hornblende slate, syenite and tremolite, and in tal- cose slates. Most of the gold veins of the State contain copper in large part, and some of the mines of copper were first opened as gold mines. It exists mostly in the form of copper pyrites, although the other common ores are of frequent occurrence.
Mica. A great many mines of this mineral have been opened in the last 3 years, in some of the western counties of the State, most of them in Mitchell county, and all of them in the Laurentian rocks. It is found in ledges (veins) of very coarse granite. Many of the plates of Mica are of remarkable size, reaching 3 and even 4 feet in diameter. It is mostly sold in Philadelphia and used chiefly in the manufacture of stoves, and the mining of it is a very profitable and rapidly growing industry.
Graphite is very abundant in the State, both in the middle and west, existing chiefly in large bedded veins, generally more or less earthy and slaty, but occasionally quite pure and crystalline. It has been wrought on a large scale at several points. One vein, a few miles from the Capital, is one of the most extensive known.
Corundum has been found in large quantities in several counties west of the Blue Ridge, and is now extensively mined. Several valuable rubies and sapphires have been already obtained, one piece having been sold in London for $4,000 : and a ruby crystal of 312 pounds is in the cabinet of Prof. Shepard, Amherst College, Mass. The principal use of this mineral however, is in the manufacture of the finer kinds of emery, for which purpose it has no equal.
Chromic Iron is of common occurrence in the same region.
Manganese. Several veins of the Black Oxide, of considerable extent have been found.