Page:Popular Science Monthly Volume 41.djvu/678

660 In the absence of these archaeological landmarks, there are other signs scarcely less unmistakable. On exposure to the atmosphere the feldspar is decomposed, the potash being washed out, and the kaolin left as an insoluble residue. If this be followed up, it is pretty sure to lead to mica, but one can not, of course, predict to what sort of mica.

In most cases the mining has been decidedly incidental in its character, and has been abandoned as soon as water was reached, or as soon as the yield of mica ceased to be immediately profitable. Other mines have had quite a history. Perhaps the most famous of the Carolina mines is the Clarissa, near Bakersville. It was opened soon after the Sink-hole, and is said to have produced more mica than all the other mines in the county combined. Its output is reckoned up in hundreds of thousands of dollars. The vein is from four to twelve feet thick, with an average of about six. It has been followed to a depth of over three hundred feet. The mine is now idle and full of water, although men who know it say that there is as much mica there as ever.

With labor at seventy-five cents a day, the primitive methods of mining are the more profitable. Steam drills have been introduced in a number of the mines, but have proved less economical than hand drilling. I do not know that the relation is strictly that of cause and effect, but their introduction has generally been followed by the closing of the mine. When the vein stuff has been blown down, it is an easy matter to separate the blocks of mica from the feldspar and quartz. When once obtained they are jealously guarded, for a clear block of mica of good size represents a value of many dollars. Each mine has its strong-room, solidly built of logs and constantly kept under lock and key. These blocks of mica are in the shape of rough hexagonal prisms (monoclinic), and if of any thickness are quite opaque. They vary in color from silver-gray and green to a rich, almost ruby brown. This last is known as "rum" mica, and sometimes commands an extra price.

The mica is seldom prepared for market at the mine itself, but is taken to a conveniently located glass-house. This generally means a transportation of several miles. Frequently the mines are on steep mountain-sides, and are only connected with the outside world by the roughest sort of trails. In this case the mica is "packed" down the mountain on the backs of men to the wagon-road in the valley below.

At the glass-house the mica is put into shape for shipment. The blocks vary greatly in size. One from the Wiseman mine, near Spruce Pine, is reported to have been six feet long by three wide. Pieces a yard in diameter have been obtained at the Ray mine, in Yancey County, and similarly large plates have been