Rutile.—Rutile
has been found of sufficient compactness and luster in Alexander
county, North Carolina, and at Graves mountain, Georgia, to be used as
a gem.(a) The rutile from the former locality, when cut, more closely
resembles the black diamond in color and luster than any other known
gem. If enough could be found fit for cutting, it would become popular
as a rich mourning gem. The rutile from Graves mountain, when cut, more
nearly approaches the garnet in color, and is therefore not as
desirable.
Hematite.—Hematite,
although found at many localities in the United States, is rarely
compact enough for cutting, and is not used for that purpose, owing to
the cheapness of the foreign mineral and cheap-cut gems sent to this
country. Some exceptionally small, richly-colored pieces have been
found near Gainesville, Georgia. The cut specimens sold at the Lake
Superior resorts are almost entirely of foreign stone and cutting.
Isopyre.—Isopyre
(b) is found in small veins from one to three inches in width at the
iron mines near Dover, New Jersey. In color it very nearly resembles
the darker green jasper, or, in other words, bloodstone without the
red spots. It is used only as a gem in the cabinets of collectors.
Prehnite.—Prehnite
(c) has been found at a number of localities iu the United States, and
gems have been cut from material found at Bergen Hill and Paterson, New
Jersey.
Zonochlorite.—Zonochlorite
has been found only at Neepigon bay, Lake Superior, and is scarcely
known as a gem, except to collectors, some of the specimens showing the
rich dark-green tints, arranged in concentric layers, and are very
beautiful.
Turquois.—This
stone has been found at three localities in the United States—Los
Cerillos, New Mexico, Turquois mountain, Cochise county, Arizona, and
at a point in Southern Nevada. At the latter place it occurs in veins
of small grains in a hard shaly sandstone. The color of this turquois
is a rich blue, almost equal to the finest Persian, and the grains are
so small that the sandstone is cut with the turquois in it, making a
rich mottled stone for jewelry. The principal sale for this stone is in
San Francisco. At Los Cerillos some pieces have a decided blue color
when found or broken, but show a marked tendency to turn green, and
usually become quite green in a very short time.
At Turquois mountain the normal color appears to be green, although at times a faint shade of blue is perceptible.
[Prof. W. P. Blake writes to the American Journal of Science, March, 1883, concerning this new locality of green turquois, as follows:
"In this Journal, March, 1858, I directed attention to the occurrence in New Mexico of a green turquois highly prized as a gem by the aborigines and known as ' Chal-che-we-te.'' The completion of the railway
