Ch. 3: Precious Gem stones in 1912

Ch. 3: Precious Gem stones in 1912 Page of 93 Ch. 3: Precious Gem stones in 1912 Text size:minus plus Restore normal size   Mail page  Print this page
GEMS AND PRECIOUS STONES.                           1045
north and south direction along the contact of granite with green­stones. Some specimens are associated with blue quartz which has doubtless come from pegmatite. The crystals found are described as green, some with rich color, translucent, weathered, and badly flawed.
FELDSPAR GEMS.
AMAZON STONE.
VIRGINIA.
Fine specimen and gem minerals have been obtained from some of the mica mines of the Amelia Courthouse region, Virginia. It is probable that the majority of them came from the A. H. Rutherfoord mine, 1-1/4 miles north of town, though the exact locality is not given in many of the descriptions of the fine minerals or on their accompanying labels in collections. Descriptions of this locality and its minerals have been given by W. F. Fontaine,1 T. L. Watson,2 and E. S. Bastin,3 and their work is drawn on freely to supplement notes made by the writer in August, 1912. Additional information was kindly fur­nished by A. H. Rutherfoord.
This part of Amelia County is typical of the Piedmont Plateau region. The larger ridges are rather flat or gently rolling and rise to approximately one general level, 350 to 400 feet above sea level. Except near the larger water courses the slopes and hillsides in the valleys are rather light. Rock weathering has been deep and out­crops are not plentiful. The rock formations are biotite schist and gneiss, in some places garnetiferous, and in others highly feldspathic, resembling granite gneiss. Some of these phases may be metamor­phosed granitic rocks. The strikes measured are generally northerly, with easterly and westerly variations. Pegmatites are common and some cut across the gneisses. The granitic rocks weather to light sandy soil and the schists and gneisses to reddish clay soils.
Fontaine mentions evidences of work by Indians or other persons at the Rutherfoord and other mica mines of this region. The mica vein is reported to have been removed to a depth of 10 feet on the outcrop and the rubbish to have been thrown back or washed into the workings. Mining by white men commenced in the Amelia mica mines in 1873 and has been more or less intermittent since that time.
At the Rutherfoord mine operations were conducted at two points about 90 yards apart in a northeast-southwest direction. The open­ing to the northeast is on a low hill and was called No. 1 by Fontaine; the other opening is in a bottom close to a branch and was designated No. 2 by the same writer. This distinction is very acceptable, in view of the fact that the first work was done at the upper place, which will be used in the following description. The outcrop at the lower place was discovered later in the stream bed, aiid the water was diverted to the north to facilitate working. At the time of Fon­taine's examination in 1883, or earlier, there were shafts less than 80 feet deep at each place. In August, 1912, opening No. 1 consisted
i Notes on the occurrence of certain minerals in Amelia County, Va.: Am. Jour. Sci., 3d ser., vol. 25, 1883, pp. 330-339. 2 Mineral resources of Virginia, Virginia Jamestown Exposition Commission, 1907, pp. 282 and 385-392. 'Quartz and feldspar: Mineral Resources U. S. for 1910, pt. 2, U. S. Geol. Survey, 1911, pp. 971-973.
Ch. 3: Precious Gem stones in 1912 Page of 93 Ch. 3: Precious Gem stones in 1912
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US Geol. Surv. 1912. Gemstones, Metals.
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