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

14 KYANITE, SILLIMANITE, AND ANDALUSITE DEPOSITS, SOUTHEASTERN UNITED STATES
very rare occurrence are corundum, diaspore (fig.
12), sillimanite, and zunyite. Other accessory minerals
are listed in table 2.
SIULJMANITE-QUAKTZ DEPOSITS
Deposits of sillimanite-quartz rock have been
found only in the Kings Mountain district, North
FIGURE 10. Photomicrograph of kyanite quartzite, from about 0.3 mile west
of Madisonville, Charlotte County, Va. Shows characteristic gneissic structure,
with kyanite (k) partly replaced by finely fibrous chromian muscovite
(m.); quartz (q), rutile (r), limonite (1), holes in section (h). Planepolarized
light.
phate goyazite, at Clubb and Crowders Mountains;
the calcium-aluminum phosphate crandallite, at
Clubb Mountain; and the aluminum phosphate
variscite found in one thin stringer in drill core
from Willis Mountain.
FIGURE 12. Photomicrograph of kyanite (k) and diaspore (d) veined by
dickite (di), Willis Mountain, Buckingham County, Va. Rutile (r) ; hole
in section (h). Plane-polarized light.
Carolina-South Carolina. Their structure and
petrography are discussed but briefly here, because
they are described more fully in the section on the
Kings Mountain district.
The sillimanite quartzite deposits are relatively
small; most of them are between 10 and 30 feet
FIGURE 11. Photomicrograph of kyanite quartzite cut by clay veinlets, from
diamond-drill hole 6 (at 116 ft), Willis Mountain, Buckingham County, Va.
Shows kyanite (k), and quartz (q) veined by clay mineral (cl). Rutile (r).
Two types of clay have been identified in specimen by X-ray and electron
microscope: (1) dickite and (2) kaolinite and (or) hallosyite. Holes in
section (h). Plane-polarized light.
Other aluminous minerals in kyanite-quartz rock
(found in moderate amounts in several deposits in
the Kings Mountain district) are chloritoid (fig. 14),
staurolite, and andalusite. Aluminous minerals of
FIGURE 13. Photomicrograph of topaz (to) and kyanite (k) in fine-grained
quartz (q), from Corbett deposit, about 5 miles west of Smithfield, Johnston
County, N.C. Rutile (r). Specimen contains about 70 percent quartz,
20 percent topaz, and 10 percent kyanite. Plane-polarized light.