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.
