DIAMOND MINING 221
edges.
It was cut to 11-11/16 carats, and though poor in color and badly
flawed, brought a large price; very much more than it was worth. It was
known afterwards as the " Dewey" diamond. No diamond as large has
since been found in the States.
The
diamonds found in this section of the country have been taken from
detrital matter, derived evidently from the weathering of the
crystalline-silicate rocks which constitute the surrounding mountains.
The gravels contain minerals similar to those associated with
diamonds in alluvial deposits elsewhere, viz., garnet, zircon, gold,
magnetite and anatase, and some monazite, a rare mineral generally met
with in the Brazil fields. The flexible sandstone, itacolumite, thought
by some to be the matrix of the diamonds of Brazil, is also found with
gold in the neighborhood of places in the Carolinas where diamonds have
been found, though no report has been made of a diamond being found in
it. The crystals are mostly octahedra and, excepting the Dewey, the
largest, found in 1886, weighed 4-1/2 carats. The first diamond found
in North Carolina came from Brindletown Creek, Burke county, in 1843.
A
few stones have been found in superficial deposits in Kentucky and
Tennessee, but without indications of the source from whence they came.
Work has been done on the peridotite dike at Ison creek in Elliot
county, and other similar dikes in northeastern Kentucky have been
prospected without success.
The
path of the glacial drift through Wisconsin, Michigan, Indiana and
Ohio, has afforded quite a number of diamonds. Most of them were found
in Wisconsin. It is supposed that they were brought down from Can-
