Elko County, Nev., are perfect gems, so splendent are they, but they are generally too small or too dark in color for jewelry.
The
finest pyrope garnets in the United States are found in New Mexico,
Arizona, and southern Colorado, where they are often called rubies. In
New Mexico they are to be found, it is believed, only on the Navajo
Reservation, where the Indians collect them in large quantities from
ant-hills and scorpion-hills, in the sand, and also, it is believed,
pound them out of the rock. They are found associated with olivine and
chrome pyroxene, and in northeastern Arizona they are found in loose
sand, having probably been brought by the action of water from a point
fifty miles to the north, where they are supposed to occur in a
peridotite rock, from which it is said the Indians pound them out with
stones. In the western part of Arizona, on the same parallel with Fort
Defiance, on both sides of the Colorado River, garnets have been
observed associated with grains of peridot, a chrome pyroxene, and a
hyaline chalcedony. They are also found on the ant-hills and near the
excavations made by scorpions, having been taken therefrom by the busy
occupants as obstructions to the erection of their galleries and
chambers. They are collected by soldiers and Indians, and sold to the
Indian traders, who send them to the large cities in lots of from an
ounce upward. The garnets have never been found in place by any of the
geologists or any surveyor of the United States Geological Survey, and
it is suggested that they are derived from some lower cretaceous
sandstone; but it is very evident, from the associated minerals, that
they have weathered out of a peridotitic rock. They are from 1/8 to 1/4
inch in diameter, rarely over 1/2, and but a few have been seen that
measure 1/2 inch across. In form they are generally quite round and
pitted, often, however, with fractured edges, as if they had been
rolled. They average well for quality ; one-half are worth cutting, and
one-quarter will furnish good stones, but fine ones are quite rare. An
interesting fact in connection with these garnets is that a large
proportion of them contain a network of fine acicular crystals,
evidently rutile from their arrangement, as has been suggested by
Babinet and Dr. Isaac Lea.1 Occasionally these grains or pebbles of garnet break in two with a conchoidal fracture, reveal-
1 Proc. Acad. Nat. Sci., Phil., Vol. 21, p. 119, May, 1869.
