Mineral resources . f their formation. At the outset it may be noted that the pyrolusite, limonite, haematite,malachite, azurite, cuprite, native copper, carbonate of lead, copper glance(chalcocite), the richer bunches of yellow sulphide of copper (chalcopyrite),as well as much of the free gold, occurs in the upper portions of the lodes;while, on the other hand, at very slight depths below water-level, these giveplace to quartz and chert, with slate, containing crystals, threads, veinlets,patches and masses of iron pyrites, galena, zinc-blende, and Mount Boppy lode, however, c
Mineral resources . f their formation. At the outset it may be noted that the pyrolusite, limonite, haematite,malachite, azurite, cuprite, native copper, carbonate of lead, copper glance(chalcocite), the richer bunches of yellow sulphide of copper (chalcopyrite),as well as much of the free gold, occurs in the upper portions of the lodes;while, on the other hand, at very slight depths below water-level, these giveplace to quartz and chert, with slate, containing crystals, threads, veinlets,patches and masses of iron pyrites, galena, zinc-blende, and Mount Boppy lode, however, consists mainly of impure quartz andsilicified slate, and its copper, iron, lead, zinc, and sulphur content is small. The minerals of the first group are those of the zone of oxidation, whilethose of the second represent the original, or primary, association of orend gangue minerals as they were deposited in the formation of the lodes. The secondary minerals may be again divided into oxides and sulphides. Plate Association of ehalcopyrite, zinc-blende, and galena in impure silica, Mount Boppy Lode. The shaded portions represent the sulphide. Tiny veinlets of quartz may be seen traversing the impure silica, x 2. Plate IX.
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectminesandmineralresou
