A N T I M O N Y : ITS HISTORY, CHEMISTRY, MINERALOGY ...
A N T I M O N Y : ITS HISTORY, CHEMISTRY, MINERALOGY ...
A N T I M O N Y : ITS HISTORY, CHEMISTRY, MINERALOGY ...
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THE GEOLOGICAL OCCURRENCE OF ANTIMONY ORES. 47<br />
blende, steinniaimite, zinkenite, and cinnabar-ochre, rarely native<br />
gold. Antimony salts of other metallic sulphides may also be found.<br />
Antimony sulphide occurs in laminar crystals or in granular forms,<br />
often massive, generally intermingled with quartz, thus forming a<br />
compact mass occupying the whole vein. Stibnite-quartz ore might<br />
be considered as an extreme development of silver or lead ore.<br />
In 1851 S^narmont, in order to explain the formation of stibnite in<br />
veins, made an experiment to obtain it by heating in a closed vase a<br />
mixture of antimony and sulphur in the presence of pure water up<br />
to 300°, or in the presence of bicarbonate of -soda at 250°. The contact<br />
rocks are occasionally similar to those of veins containing lead<br />
ore, rocks having white mica and green minerals. Hereafter this<br />
type is denoted by A.<br />
(a) Sub-Type : Antirnonial Gold-Quartz Veins. The stibnite is<br />
itself gold-bearing, and accompanies other free gold-bearing gangues.<br />
Hereafter this sub-type is denoted' by B.<br />
2. Beds of epi-minerals, i.e. impregnated non-calcareous rocks. In<br />
this case the antimony ore is impregnated in the rocks. Hereafter<br />
this is denoted by C.<br />
3. Epigenetic Stocks. The type is a metasomatic antimonial<br />
deposit. Hereafter this type is denoted by D.<br />
4. Bedded Deposits of antimony ore. The deposits are of sedimentary<br />
origin. Some of the so-called bedded deposits may be due to the<br />
impregnation of the country, i.e. of the neighbouring rocks. Hereafter<br />
this is denoted by E.<br />
In the following we shall take up the antimonial deposits of each<br />
country in turn.<br />
GERMANY.<br />
Ores of antimony sometimes occur in the Devonian rocks of<br />
Rhenish Prussia between Wintrop and Mentrop, four miles from<br />
Arnsberg, where are found bands of bituminous limestone from<br />
6 inches to 18 inches in thickness, interstratified between clay<br />
wlates and siliceous shales. Stibnite penetrates all these strata,<br />
which are overlain by Millstone Grit. It is-also noticed that the<br />
stibnite accumulates more plentifully towards the middle part of<br />
the various beds, but gradually thins out near the bedding planes of<br />
deposition. Sometimes fragments of the "country" are included in<br />
the more massive portions. (D.)<br />
At the Hoffnung mine, near Briick, on the Ahr, the Devonian<br />
graywacke slates have a N.-S. strike, with a dip of 45° towards the<br />
west, cut through by N.-E. veins, dipping from 40° to 50° S. The