The weekly Butte record., 1863-05-16

Prospecting for Copper.

As the attention of prospectors, in Calitor'
MA, at this time, appears to be very generally
directed to Copper. as present speciality, we
have thought it might be opportune to give
few hints which NAV be OF service 10 such re
searches. and which We find in the Mining and
Scientific Press:
The ores Of copper are quite numerous and
present great diversity of appearance; yet
they are all very readily distinguished by GER
tain chemical reagents, from non-copperous
ores. The presence of copper in any ore, even
to as low per centage as fraction OF only
one per cent, may be readily asceFtalned by
first calcinng aud then finely pulverizing The
ore and suhjecting it to a bath OF water OF am-
monia. when, if copper is present, the water
will assume blue tinge, more or less intense,
according to the amount of copper in the ore
A teaspoonful Of pulverized ore dropped into a
two ounce vial two thirds filled with the above
mentioned liquid is about the proper proper
tions to be employed 10 the test. Nearly ali
the ores of copper may be readily distinguished
after a little experience, from the appearance
OF greenish tint upon their surface, more or
less observable, and sometimes verging upon
purple or blue.
The ores of copper are divided, by metallur-
gists, into Is different classes, and each class
is subdvided into many varieties. The richest
of the ordinary ores appear under two general
aspects the first having metallic lustre of
copper red, brass yellow, iron or blackisb gray.
at times inclining to blue; the second is with
out metallic appearance, of reddish color, verg-
ing upon purple, blue or geeen. the last being
the most usual tint The classes of ore most
frequently occurring are Native Copper, Sui
phuret of Copper Copper Pyrites Gray Cop
per, Sulphate of Copper, Carbonate of Copper
and Arseniate Of Copper. Native Copper, so
far as we have learnad, has never been found
to any extent in this State, although it occurs
in greater or less abundance in most other
copper regions hitherto explored. 1t is found
in greatest abundance in the mines on the
Southern shore of Lake Superior. The most
common ores Of copper are sulphurets and OK
ides, the former being the most abundant.
Sulphuret of Copper occurs in all considera-
BILE copper districts, aud especially in Corn
wall This is also class of ore which seems
to be very abundant in California. The color
~ &c oh bir,rr
at times to tarnished blue or green. 1t is con-
sidered one of the richest ores and generally
occurs in very heavy veins.
Copper Pyrites greatly resembles, in appear
ance, sulphuret of iron, common in the gold
bearing quartz of this State, and will probably
prove the most abundant Of the copper ores on
the Pacific Coart. This, with the sulphuret
Of copper, forms the chief yield of the copper
mines of Cornwall The color of the Pyrites
is brass yellow, subject to tarnish, with green
ish black streaks and uneven fracture.
Copper Pyrites are readily distinguished
from iron pyrites which they greatly resemble,
by their inferior hardness; they may be cut
with knife, while iron pyrites will strike fire
with steel A marked difference may also be
noticed in the effects of nitric acid upon the
two substances. They do not form so rich an
ore as sulphurcts. The richness of the Pyrites
may generally be judged by their color. If
they present a fine yellow hue, and readily
yield to the hammer, they may be considered
good ore; but if they are hard aud Of pale
yellow color, they are mixed with iron pyrites,
and consequently comparatively barren Of cop
per, and constitute poor quality of ore.
Carbonate of Copper is of a light blue or
green color, with pale green streak. 1t often
occurs in beautiful green chrystals. 1t is also
known as Malachite. Green Malachite or
Green Carbonate of Copper admits of high
polish, like marble. and when obtained in large
slabs is often formed into tables, mantel pieces,
etc.
Arseniate of Copper is Of various shades of
olive Green, and sometimes occurs in beautiful
blue chrystals. 1t readily melts before the
bow-pipe, throwing off fumes of garlic odor.
This ore is but little worked
Gray Copper ore is of steel gray color,
more or less deep, either bright or dull The
value of this ore is often very materially in
creased by reason of the silver which it con-
tains. 1t is generally accompanied, to great
er or less extent, with copper pyrites.
Sulphate of Copper blue yitriol,l is similar
to the artificial salt of the laboratory The
water flowing from mines of this variety of ore
is of a blue tint, caused by the solution of this
salt Copper is easily obtained from this
water, in metallic state, by depositiug pieces
of scrap iron in it.
The ores above named are about all the ores
Of copper which are worked to any extent
The copper of Lake Superior contains about
310ths of one per cent. Of silver. The copper
of this State, mostly if not ALL doubtless cou-