The Placer herald. [volume] (Auburn, Placer County, Calif.) 1855-1991, 1863-03-07
PROSPECTING FOR COPPER.

|
directed to Copper, rs y present speciality
We have thought it might be opportuns to
give few hints which may be of service in
such researches.
The ores of copper are quite numerous
and present great diversity of appearance,
yet they are ali very readily distinguished by
certain chemical reagents, from non-copper-
Gus ores. The presence of copper in any
ore, even to as low per centage rs frac-
ton OF only one per cent may be readily as
certained by being first calcined and then
finely pulverizing the ore and subjectng it
to bath Of water and amonia when, if cop
per is present, the water will assume blue
tinge, more or less intense, according to the
amount of copper in the ore. A teaspoon
ful Of puverized ore dropped into two
ounce vial two thirds filed with the above
mentioned liquid is about the proportions of
the test Nearly all the ores of copper may
be readily distinguished, after little experl
ence, from the appearance Of greenish tint
upon their surface, more or less observable,
and sometimes verging upon purple and
blue
The ores Of copper are divided, by metal
lurgists, into thirteen different classes, and
each class is subdivided into many varieties
The richest of the ordinary ores appear un-
der two general aspects the first having a
metallic lustre of copper red, brass yellow,
iron or blackish gray, at times inclining to
blue; the second is without metallic appear
ance, of reddish color verging upon purple
blue or green, the last being the most usual
tint. The classes Of ore most frequently
occurring are Native Copper, Sulphre, OF
Copper, Copper Pyrites, Gray Copper, Sui.
phate Of Copper, Carbonate of Copper and
Arsenia,e o! Copper. Naive Copper, so far
as we have learned, has never been found to
any extent, in this State, although it occurs
in greater or less abundance in the mines on
the Southern shore Of Lake Superior. The
most common ores of copper are SUI phurets
and oxides, the former being the most abund
| ant.
Sulphuret of Copper occurs in all consid-
cradle copper districts, and especially in
seems to be very abundant in California;
The color Of this ore is blackish lead gray,
approaching, at times, to tarnish blue or
green. 1t is considered one Of the richest
ores, and generally occurs in very heavy
veins.
Copper Pyrtes greatly resemble, in ap-
pearance, 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 Coast. This, with
the sulp phuret of copper, fo'ms the chief
yield of the copper mines Of Cornwall. The
color OF Pyriles, is brass yellow, subject to
| fnrnv, ,uitb r,roon;eh hI,,,l-
ven fracture.
Copper Pyrites are readily distinguished
from iron Pyri,es, which they greatly re-
sembe, by their inferior hardness; they may
be cut with knife. while iron pyries 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 sulphurates. The
richness of the Pyrites may generally be
judged by their color. If they present a
fine yellow hue, and readily yield to the
hammar, ley moy be considered good ore;
but if they are hard and of pale yellow
color, they are mixed with iron pyrales. and
consequently are comparatively barren of
copper, and constitute poor quality of
ore.
Carbonate of Copper is of light blue or
green color, with pale green streak. 1t
is also known rs Malachite. Green Mala-
chite or Green Carbonate Of Copper admits
Of high polish, like marble, and when obtain.
ed in large slabs, is often formed into tables,
mantel- pieces, etc.
Arsenic of Copper is Of various shades Of
olive green, and sometimes occurs in beauth
ful chrystals. 1t readily melts before the
blow pipe, throwing off fumes of garlic
Gray Copper ore is Of a steel gray color,
more or less deep, either bright or dull
The value of this ore is often materially in
creased by reason Of the silver which it con
lains. 1t is generally accompanied to a
greater or less extent with copper pyrtes.
SuIphate of Copper (BIue vitro) is SINH
lar to the artificial salt Of the labratory.-
The water flowing from mines of this varie-
of ore is of blue tint, caused by a sou'
ton of this salt. Copper is easily obtained
from this water in metallic state, by depos'
itiog pieces of scrap iron in it.
The ores above mentioned are about al
the ores of copper which are worked to any
extent. The copper Of Lake Superior con-
tains about 8 lO;hs of one per cent of sill
ver The copper of this State, mostly if
not ALL doubtless contains an appreciable
quantity Of gold and silver. Of this we
shall probably receive more definite knowl.
edge when full returns are received from the
ores which have been shipped East for rel
duc,on. Many Of the mines now being
explored for copper, have heretofore been
worked for gold, and abandoned because
they would not pay. As our miners became
familiar with the characteristics of copper
ores these mines are being rapidly re located
and worked for their legitimate yield,
which. rs general thing, will be found to
be much more profitable and enduring, than
any ordinary yield Of the more precious met'
al, so generally sought for in California. A
little science will be found Of vast Importance