A N T I M O N Y : ITS HISTORY, CHEMISTRY, MINERALOGY ...

50 THE METALLUBGY OF ANTIMONY.
perhaps from effusive lava flows. The origin of the antimony deposits
is traceable to the igneous rocks.
The ores appear in three different forms :—
(1) Tufts and stringers of stibnite, quartz, and calcite in decomposed
trachyte, as found in the mines of Kik and Stolitza. (C.)
(2) Antimony veins in the slates. At Hovin6 there occurs a compound
vein, dipping at 30°. Transverse stringers containing stibnito
are enclosed between two parallel bounding fissures, of which the
foot-wall is always the richest, while the hanging wall is mostly
barron. (A.)
(3) Interbedded ore masses. The deposits of this kind consist
mainly of a dark, very finely crystalline ground-mass of quartz,
intimately intergrown with tufts of stibnite. They lie between an
FIG. 1. —Bod-Hko deposit of antimony ore near Kostainik.
A, Clay alato.
B, Quartz layor with antimony
oro.
0, Clay.
D, Limestone.
E, Trachyte,
overlying slate and an underlying limestone, and are always accompanied
by a trachyto intrusion near by, which sonds out narrow
apopbyses, forming sometimes the walls of the deposits, or cutting
through them in a parallel direction or at an acute angle. This is
shown in fig. 1. (I).) The stibnite has mostly been suporficially
altorod into antimony-ochre, stiblite, or valentinite, and in many cases
it has been entirely leached out, leaving a skeloton of gray quartz
behind. At times the quartzose ore has been crushod and rocemented
together by quartz or calc-spar.
At other places—as, for instance, in the Zavorio III. mine (fig. 2) —
the ore-bearing quartz mass cuts into the underlying limestones with
very irregular borders, thus suggesting the idea that considerable
portions of calcium carbonate have been leachod out and replaced by
the quartzose ore. (D.)