Kyanite, Sillimanite, and Andalusite Deposits of the Southeastern ...

ANDALUSITE DEPOSITS 109
cut at Brasstown Church contains about 4 percent
sillimanite (Furcron and Teague, 1945). The other
sillimanite locality is in the area of massive kyanite
deposits near Old Johnstown, Dawson County,
where small flattened pebblelike masses of finegrained
fibrous sillimanite and quartz occur in coarse
biotite gneiss; the sillimanite content of one of
these small lenses was determined by microscopic
examination to be about 25 percent (Furcron and
Teague, 1945).
ALABAMA
Sillimanite schist was found in Randolph and Clay
Counties, Ala., by W. T. McDaniel, Jr., of the Tennessee
Valley Authority, in 1944, according to
Teague (1950); the extent and quality of these deposits
have not been investigated.
ANDALUSITE DEPOSITS
VIRGINIA
Andalusite has been found in Fairfax County by
Charles Milton (written communication, 1953), of
the Geological Survey. It occurs with quartz in
quartz-mica schist at the edge of bodies of greenstone;
usually the andalusite is completely sericitized.
Andalusite, kyanite, and coarse muscovite
occur in quartz in andalusite schist near Difficult
Run, about 1.6 miles north-northwest of Oakton.
Andalusite schist is also found in the old railroad
cut just south of Virginia Highway 211, about 1*4
miles east of Sisson. Andalusite is reported to
occur with kyanite and corundum on a knob of Bull
Mountain near Stuart in Patrick County (Genth,
1890); we were not able to find this locality.
NOKTH CAROLINA
Andalusite occurs in mica schist and in sillimanite
quartzite in the Kings Mountain district, and
is present in some abundance in several of the
North Carolina pyrophyllite deposits; it was first
recorded from the Gerhardt (Staley) pyrophyllite
mine by Burgess (1936). The pyrophyllite deposits
are lenticular bodies that seem to have been formed
by hydrothermal replacement in silicified zones in
silicic volcanic rocks (Stuckey, 1928). The deposits
all occur in the Piedmont belt of volcanic
rocks and slates (pi. 1). The occurrence of andalusite
and lesser amounts of other high-alumina minerals
(diaspore, topaz, and kyanite) in some of
these pyrophyllite deposits has been described by
Broadhurst and Councill (1953). They point out
that in some deposits the footwall is nearly pure
quartz rock and the hanging wall is sericite schist.
The deposits were examined briefly by us, but not
mapped, following the discovery of andalusite by
the North Carolina State geologists. The descriptions
given below are taken mainly from our own
field observations and petrographic studies.
BOWLINGS MOUNTAIN, GRANVIIXE COUNTY
A pyrophyllite deposit about 1,000 feet long
trends N. 15° E. along the ridge of Bowlings Mountain,
about 3 miles northwest of Stem. Massive and
crystalline pyrophyllite occur in very fine grained
siliceous zones in sericite schist. Tough white
granular rock containing coarse-grained andalusite,
quartz, and pyrophyllite is present in parts of the
deposit (fig. 17). Light-gray to tan dense chertlike
topaz, identical in appearance with the dense
topaz from the Brewer deposit, South Carolina, is
abundant as float to the east of the northern end of
the deposit, and also occurs as stringers a few
inches thick in pyrophyllite in the southernmost
opencut. The deposit was prospected by a shallow
opencut shortly before the time of the pyrophyllite
investigation by Stuckey (1928, p. 57); it was then
known as the Harris prospect. The Carolina Pyrophyllite
Co. began work here about 1949 or 1950.
The rock is being mined from 2 opencuts and
trucked to the grinding plant at Staley, about 80
miles to the southwest.
Another deposit of pyrophyllite occurs on a prominent
ridge rising nearly 200 feet above the surrounding
countryside, about 14 miles northeast of
the Bowlings Mountain deposit, 9 miles northwest
of Oxford, and about IVa miles east of North Carolina
Highway 96. Float and low outcrops of dense
siliceous rock are abundant for about three-quarters
of a mile along the ridge. Chloritoid occurs in
some rock; disseminated hematite and magnetite
are also present. Blocks of massive pyrophyllite, 1
to 2 feet long, are distributed along a distance of
600 to 700 feet at the north end of the ridge. Other
aluminous minerals have not been discovered.
HILLSBORO, ORANGE COUNTY
A deposit of pyrophyllite on a prominent ridge
just south of the town of Hillsboro, Orange County,
was prospected by the North State Pyrophyllite
Co. in the fall of 1952. Opencut mining was started
here a few years later. The andalusite-pyrophyllitequartz
ore is shipped to the company's plant at
Pomona, N.C. (near Greensboro), where it is
blended with other materials and used to manufacture
firebrick and brickkiln furniture.
A body of andalusite-pyrophyllite-quartz rock
over 1,200 feet long and 50 to 150 feet wide has been