Mr.
Hamilton describes the obsidian as occurring in parallel " veins " from
6 inches to 2 feet in width, but gives no particulars as to their
position or direction. The colors are black, opalescent, and green
with dark bands, also a lighter green without banding. He has had
specimens polished for sleeve buttons and like purposes, and it appears
to be capable of ornamental use and to be procurable in abundance, as
Jlr. Hamilton states that it can be picked up by wagonloads at the
outcrop.
UTAHLITE (VARISCITE). UTAH.
A
very interesting discovery has lately been announced of a new
occurrence of this attractive and wholly American gem stone, hitherto
obtained from only one locality—at Mercur, Tooele County, Utah—first
made known in 1804 and described in the report for that year.a
The new occurrence is also in Utah, and the particulars regarding it
are furnished by Mr. Edward Bird, of Salt Lake City. The location is
about 20 miles northwest of the other one. and lies 8 or 9 miles west
of Stockton and some 40 miles southwest of Salt Lake City. The mineral
appears in a ledge which crosses a little spur or foothill running
eastwardly from the main range of the Stansbury Mountains. This hill is
some 1,500 feet long from east to west, and rises to a maximum height
of 200 feet above the adjacent " bench lands." The variscite occurs in
two seams or ledges which traverse this foothill in a northerly and
southerly course, dipping steeply westward. The only development thus
far done is an open cut on the south side of the foothill or spur, some
10 feet long and 4 feet deep. The surface rock appears to be an
iron-stained brecciated quartz. At the west end of the hill, where a
little depression separates it from the main Stansbury range, there is
an outcrop of brownish laminated quartzite: at the east end appears a
strong body of bluish limestone. No metallic veins have been observed
in the vicinity.
The
variscite itself occurs in the same manner hero as at the Mercur
locality, in roundish or kidney-shaped nodular masses from the size of
a lemon to that of a large cocoanut, with a rough external coating or
casing of reddish-brown color, inclosing the beautiful green material
within. Mr. Bird observes that this color tends to become deeper in the
lower part of the cutting, suggesting an increase of richness with
depth; but this point lias not yet been established, he also thinks
that slabs can be cut from the compact rock, showing the variscite
contrasting with the reddish-brown quartzose matrix. Little lias yet
been regularly taken out, but enough to show the fine color of the
green interior, and a number of persons have had charms and ring stones
cut from it.
PSEUDO-SERPENTINE. WASHINGTON.
In
a report of this Bureau a description has been given of a very handsome
serpentine from the State of Washington, exhibited at the Buffalo and
Charleston expositions. A recent article by Prof. F. \V. Clarke '
gives an account of some remarkable peculiarities in this mineral,
which lead him to designate it as a " pseudo-serpentine." Analysis
shows that it contains a large proportion of (apparently) brucite,
intimately mixed with some serpentine, and also a
a Sixteenth Ann. Kept. V. S. Geol. Survey, pt. 4. 1894. p. (in:;.
b Clarke,F, W., Contrib. to Mineralogy: Bull. U.S. Geol. Survey No .212, 1905, pp. 69-71.
