until
recently received much recognition, owing to the high price of cutting
sapphire gems and the small demand existing for stones other than of
deep color, such as true ruby red or sapphire blue. In 1889 an area of
about 4,000 acres (6-1/4 square miles) was purchased, or the option
obtained upon it, by a company capitalized at £450,000, which
contemplates working Eldorado bar and the other bars for a distance of
about 6 miles.
The
company has had the property examined by mining engineers, whose
estimate is that Eldorado bar will yield some 2,000 ounces of sapphires
to the acre. Only a part of these, however, may be of such quality as
to warrant cutting for gems. The stones found exhibit a great variety
of colors, chiefly the lighter shades of red, yellow, blue, and green.
The latter tint is found quite pronounced, being rather a blue green
than an emerald green. Nearly all them, when finely cut, have an
apparent metallic luster, strikingly peculiar to the stones from this
locality. No true red rubies, nor true blue sapphires, the colors
demanded by the public, have been found, the other shades having thus
far been only sought by the collectors. It is claimed that there is an
abundance of gold, and time only can tell whether the enterprise can be
a success.
Several
minor companies have been formed or are contemplated. One, known as the
Spokane Sapphire Company, embraces that part of the river, near Stubbs
ferry, and on what is known as Spokane bar, and one is said to have
been formed to protect the interest of the Montana Sapphire and Ruby
Company. At all these bars the sapphires are principally found in a
layer of auriferous glacial gravel a few inches in thickness, which
reposes directly on a slaty bed rock. While work was going on at Ruby
bar, a mastodon tusk, 3 feet in length, was found in the sapphire layer.
Among
some of the associated minerals observed were white topaz in brilliant
crystals not over one-fourth of an inch in length, similar to those
from Thomas mountain, Utah; rouuded grains of garnet, sometimes as
large as a pea and rich ruby red in color, often erroneously called
rubies; cyanite in broken translucent crystals, which are white with
blue patches, one-half an inch in length and one-eighth of an inch in
diameter; cassiterite (stream tin) in rolled concentric nodules, none
over one-fourth of an inch in diameter; limonite pseudomorph after iron
pyrites, in a variety of imitative and concentric shapes, showing a
radiated structure when broken; chalcedony in small irregular and
imitative pieces, often an inch in length; and white calcite in small
rolled masses.
In
regard to the original source of the sapphire itself it is worthy of
note that during the winter of 1889 and 1890 an eruptive dike was found
cutting the slaty rock at Ruby bar, on which rests the glacial gold
gravel. In this eruptive rock were found crystals of sapphire, pyrope
garnet, and sanidine feldspar. There seems little doubt that all the
sapphire along the bars of the Missouri river has come from the
Flickr
Stumbleupon
Scribd
