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CORUNDUM GEMS.
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23
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In
Haywood County, 2 miles northeast of Pigeon river, near the crossing
of the Asheville road, and 2 miles north of this, on the west fork of
Pigeon Eiver, at Presley mine, are found some of the finest colored
specimens of blue and grayish-blue corundum, in a pegmatitic dike, and
also near Eetreat post-office (see PI. IV, B). At Newfound Gap, red
corundum occurs in an outcrop of dunite.
Twenty
miles northeast of the Presley is the Carter mine in Buncombe County,
where fine white and pink corundum occurs in crystals and in a
laminated form in peridotite. Blue, bluish-white, and reddish varieties
occur at Swannanoa Gap: and also a little south of the town of
Democrat, corundum appears,—all in the same or similar rock.
Yancey
County has several localities, the most noted of which are Celos Ridge,
8 miles southeast of Burnsville, where crystals occur in a decomposed
gneiss, and Egypt, 10 miles west of the same town, where white
crystals, sometimes mottled with blue, are found directly in the
decomposed peridotite (dunite). This occurrence is noted as of much
interest, by Lewis1 and Pratt,' for although corundum is
very largely associated with the rock, the crystals are rarely found
actually enclosed in it.
Northeast
of these mines, in the line of strike of the whole country rock,
corundum is found in gneiss near Bakersville, in Mitchell County; and
also southwest, in Madison County, near Marshall, a little north of
where Big Ivy Eiver enters the French Broad; here the rock is
amphib-olite.
Grouped
together under the name of the Blue Eidge tract, are a number of
localities where the corundum occurs in long bands of quartzose schist
that belong in and with the gneisses among which they occur. This was
referred to before as a very distinct mode of occurrence, in that the
rocks are altered sediments, and the corundum, a product of metamorphic
action rather than igneous. These corundiferous schists have been
traced for many miles along the crest of the Yellow and Chunkygal
mountains. The content of corundum is very small, and these deposits
will not be important sources for some time to come. Dr. Pratt makes 4
local divisions:—The Scaly Mountain tract, at an elevation of some
4,500 feet on the southern and southwestern slopes of those mountains,
near the headwaters of Beech Creek, a tributary of the Tallulah; the
Poster tract, just over the line in Georgia; the Yellow Mountain tract,
on the northern slopes of those mountains; and the Chunkygal tract,
near the headwaters of Sugar Cove Creek, on the western slopes of the
mountains. The first
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