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PLATINUM.
American occurrences.—Platinum,
either comparatively pure, but more commonly alloyed to a considerable
extent with iridium, osmium,or other metals of the same group, is found
in small quantities in many of the gold placer regions of the Far West
and Pacific coast, notably in California; and also occurs associated
with placer gold in Virginia North Carolina, Georgia, and other
Southern States. A nugget of platinum found near Plattsburgh, New York,
weighing 104.4 grains! described in the American Journal of Science, III., xxi., p. 123,1881.
Platinum
usually appears in the form of small rounded and flattened grains. The
occurrence of platinum in the United States thus far bag been a matter
of scientific interest rather than of any economic importance. Small
quantities have from time to time been saved from the sluices
of hydraulic mines, but were merely kept as a matter of curiosity, In
1877, 1878, and 1879, an irregular search was made for it in view of
the then existing and prospective demand for the metal for incandescent
electric lighting, and samples were obtained from many points, but many
of the localities reported in the Southern States, as well as
elsewhere, failed to afford specimens when specifically tested. No
platinum in place, that is as ore in a lode, has as yet been
discovered; its occurrence being confined, as above stated, to the
placer deposits. A vein of platinum is reported to have been recently
discovered near Hailey, in the Wood Eiver country, Idaho, and small
shipments of the ore have been made to the smelting works at Omaha.
Although this find is called a vein, in the absence of definite
particulars it is reasonable to assume that the metal is found in the
usual form of stream platinum.
It
is quite probable that in the future the production of platinum in the
United States may become a regular industry; though from the
indications which have been observed it does not appear likely that it
will ever reach any very considerable importance. The quantity of
American platinum marketed in 1882 was about 200 troy ounces. There
are no regular quotations for the domestic metal. One manufacturer
reports that the crude, unrefined American platinum which he has
handled ran as low as .520 in fineness, as against .850 for the
average crude Eussian.
The
method of mining is analogous to that of placer gold, with the
exception that the apparatus for saving platinum depends upon gravity
alone, and not upon gravity and amalgamation. The plant required for
manufacturing platinum is simple and inexpensive, and the art has been
developed to a high extent in this country. The best crucibles, etc.,
are made by hammering plate of the greatest possible density into 442
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