and
yellow mixed through gray. The color is evenly distributed in some
parts and grades from one to the other in other parts. The material has
a dense texture very closely resembling the novaculites of Arkansas.
Some of it would pass as chalcedony and some has so much impurity in
the nature of iron oxide as to resemble jasper. None of it has been cut
for ornamental purposes, but the colors would prove attractive.
ARKANSAS.
Mr.
F. Holstein, of De Roche, Ark., mentions the occurrence of a bed of
brecciated agate-like rock found along the southern border of the
Novaculite Mountains, in the northern part of Hot Springs County, Ark.,
which has many of the qualities desirable in an ornamental stone. When
polished the stone shows a brecciated structure with various colors
exhibited by the different pebbles and fragments. These fragments are
inclosed in a cement of chalcedonic material. It is possible that this
bed is a phase of the novaculite, which, as is well known, grades into
material indistinguishable from ordinary chalcedony. Some of the
novaculites of Arkansas have an exceedingly dense grain, a waxy luster
resembling chalcedony, and various bright colors. Prominent among these
colors are different shades of pink, red, brown, and yellow scattered
in various patterns through gray and white matrix. The color and
texture of such novaculites render them quite suitable for ornamental
purposes.
COLORADO.
Specimens
of agate received from Mr. J. D. Endicott, of Canon City, Colo., were
found by him at a new locality in Pueblo County, the exact location of
which is not given.
These
agates are very delicately banded, showing bright and dull red and
brown layers interbanded with gray and white chalcedony. Some of the
speoimens show a fortification structure and others a concretionary or
spherical structure. In some of the translucent gray bands there are
small rounded red spots as in the St. Stephen stone variety of agate.
The texture is very close-grained and the stones would take a fine
polish. The coloring is sufficiently rich without artificial
intensifying to make a good grade of agate jewelry.
MONTANA.
Mr.
Paul E. Hanson, of Billings, Mont., forwarded to the Survey various
specimens of agate, chalcedony, and associated minerals that have been
gathered from the gravel deposits lying along Yellowstone River and
covering much of the adjacent country. In this report for 1913,
specimens of moss agate from the same region, also loaned by Mr.
Hanson, were described, and the present notes cover certain associated
varieties of agate. Among these is a slice from a cobble 3| inches long
and 2 inches thick which shows a streak of wavy banded agate surrounded
by dark-green mottled prase. This streak of wavy agate also contains a
large proportion of green intermixed, resulting from the presence of
minute particles or scales probably of an iron silicate mineral, such
as chlorite. Another specimen consists of banded bluish-gray, brownish,
and white agate crusted over with quartz crystals, the tips of which
show a pale amethystine color.
