antimony - Sciencemadness.org

52 THE METALLURGY OF ANTIMONY.
are cut by numerous veins of granulite, along the axis of which one
often finds veins of quartz charged with antimony sulphide. (A.)
At Bresnay, east of Allier, and at Montignat, west of Montlugon,
there is observed, in addition to metamorphism, a common origin fox*
the stibnite and the rock containing white mica, as if the antimony
had been leached out of the rock by underground water. (C.)
The most important of the deposits in the Central Plateau are
those which have been worked at Freycenet, Licoulne, etc., in
Puy-de-D6me, Cantal, and Haute-Loire. These deposits are enveloped
in the fundamental or primitive formations of gneiss, mica-schist,
and granite. The veins, being generally vertical, contain lenses of
stibnite, separated at intervals by quartzose gangues. Sometimes
the stibnite is intimately mixed with the quartzose gangue, and
nearly always it is accompanied by iron sulphide. (A.)
Mention may be made of the antimony deposit at Ardeche, which
has been spoken of as sedimentary in origin (E). But it may be
an impregnation or a metasomatic alteration of the Triassic dolomite
in which the deposit is found (C or D).
In Corsica the veins occur in sericite schist, the gangue minerals
being quartz, calcite, blende, and, rarely, pyrite, cinnabar, and
bournonite.
Besides the above-described localities, the following may be mentioned:
Auvergne, Gard, Aude, Vende'e, Lyonnais, Bouc, Sopt6nic»
near Marseilles.
ITALY.
The principal deposits are found in the province of Tuscany and
in the island of Sardinia. The Pereta mine in Tuscany is opened in
a mass of chalcedonic quartz, in which stibnite is sparsely and
irregularly disseminated, thus rendering its winning difficult and
costly, especially since the quartz is very hard. According to
Coquand and Toso, the mass of crushed white quartz exists in tho
form of a great ellipsoid, of which neither the hanging wall nor tho
foot wall can be exactly determined, intercalating Eocene calcareous
shales in the north and cutting Miocene limestones in the south.
Hydrogen sulphide (jputizze) has been detected to the north of tho
outcrop. The stibnite is found in the form of stringers and pockets
enclosed in the sulphur-bearing quartz, which is sometimes encrusted
with stibnite, enclosing in turn small crystals and aggregates of
sulphur. Undoubtedly the enclosing rocks have been subjected to
metamorphism and have been impregnated with sulphurous emana-