State,
lat. 47 north, long. 117 west. This point is about midway between the
Coeur D'Alene and the Nez Perces Indian reservations, near Moscow,
Idaho, almost on the line of Idaho and Washington. The material was
rather plentiful, as the last 4 feet of the rock contained cavities
filled with precious opal. The rock is a basalt in which most or nearly
all the feldspar and pyroxene, as well as the green mass, appears to
have been altered. Some original constituent may have changed, but
whether or not it is olivine it is difficult to determine, because of
the crystalline aggregate character of tire pseudomorphic mass. The
pieces vary from the size of a half pea to that of a hen's egg, and are
found in vasicular lava; the smaller nodules are very rich in color,
but the larger ones often have little or no play of colors. The quality
of some of the specimens examined was very fine, and if the material is
as abundant as supposed, and is properly worked, it is likely to be one
of the most promising of our precious stones, from a financial point of
view. Mine buildings have been erected and the locality has been named
Gem City. A company was organized in June, 1891, under the laws of
Colorado, with a capital of $250,000, and the operations commenced in
July. Up to the first of October about $280 was expended for mining and
supplies, and after paying for lapidary work and other expenses, the
yield was $3,500 worth of opals, which were sold at from $30 to $55 a
carat. Some of these prices were in excess of that of Hungarian
material of equal or finer quality. This spring, owing to the unusual
weather, about three weeks' time was lost, and work was interrupted by
water and snow three times; still, with an expenditure of about $1,200
up to date, the results have more than doubled in both quantity and
quality, one very superior stone having been found and sold at an
extraordinary figure—much higher than the prices quoted above. The work
is carried on by about 20 men, and is much in the nature of an open
quarry. As it progresses into the hill the top soil becomes deeper, but
the layer of black basaltic rock next to it and overlying the softer
opal-bearing rock remains of about the same thickness. Considerable
veins of ocher are met with and various kinds of clay; and good opals
are often found embedded in so-called "soap holes,"in a greasy,
fine-grained, and very tenacious clay. Kernels of opal, all of good
quality, are found in hollow amygdules in the rock, the cavities being
generally larger than the opal.
Hyalite.—Hyalite,
transparent and in great quantity, breaking with an apparent
starch-like fracture, has been found in Lake county, California, by
Mr. H. H. Myer. Very fine hyalite in thick seams was observed in the
trap rock at the falls of the Willamette river, at Oregon City, Oregon,
and in beautiful botryoidal masses in the Weiser valley lava fields,
about 20 miles north of Weiser, Idaho; at both the latter localities it
is equal to the hyalite from Waltsch, Bohemia.
Garnet.—Large
quantities of purple almandine garnet, in the form of rolled fractured
pieces, have been found along the Columbia river in
