The White Pine news. [volume] (Ely, Nev.) 1906-1910, 1909-09-22
GOOD HINT TO
P%R0SPECT0RS
HOW THEY MAY DETERMINE
PRESENCE OF VARIOUS MIN
ERALS WITH FAIR DEGREE
OF ACCURACY.

Judging by the number of worth
less samples submitted to assayers
to be tested for various metals and
by the fact that valueless minerals
are often supposed to be valuable
ores, it is evident that many do not
realize how easily some elements
may be detected. Naturally a pros
pector can not be expected to burden
himself with the equipment of a
chemical laboratory, but an outfit
consisting mainly of a few chemicals.
blowpipes and spirit lamp, adds
little bulk or weight and may be of
inestimable service.
The purer the substance to be
tested the better, and should the min
eral be scattered through the rock in
fine particles, it is usually well to
first concentrate. it by pulverizing
the sample and then panning in
water, the concentrates being subse-
q~uently dried, and If necessary
ground finer. A clean six-inch frying
pan is very convenient, both for
washing and drying what is left.
Gold ores, when crushed and pan
ned, generally show either free me-
tallic gold or SUPPLIES, or other con-
centrates containing gold, which,
however, is not visible. If these
sulphides be roasted rel a fire at a
dull red heat, on thin sheet iron,
say a piece of tin can, and then re-
ground in a mortar to polish the gold
the metal in many cases will be plain
ly seen on panning again. Should
u -.zk~-: - ~-.J,.0I n-I uyhon
powdered and PANIED, show nothing
but the magnetic oxide of iron, COM
monty, called "black sand" the sam
pie is apt to be worthless or very
low grade, for the writer's experience
leads him to believe that, as a gen.
eral thing, the black sand itself OBJ
tanned from rock in place carries
little or no gold. The dried black
sand can be readily picked up with
a magnet.
Greenish rocks are sometimes mis-
taken for ores of copper, which met
al may, however, be easily detected
in the following manner: Pour into
a test tube, say half ar inch in
diameter, enough of the finer ground
material to cover the bottom to a
depth of about half an inch, add
two or three, times as much strong
nitric acid and boil gently over an
alcohol lamp until the acid seems to
have no more effect and red fumes
have ceased to come on. Dilute the
solution with one or two volumes of
water and hold a clean, bright piece
of iron or steel, such as the blade of
a pocket knife, in the liquid for a
few moments, when, IL present, a
thin film of metallic copper will be
plainly seen on the blade upon with
drawing and dipping it in clean
water. -
Instad of testing this solution
with iron or steel, strong ammonia
may be added in exces to the liquid
when cool, that is, the test tube,
after :. being we'll shaken, should
smell of ammonia. The addition of
the ammonia generally produces a
reddish brown precipitate. due to
iron, and the tube should be set
aside for a few minutes until this
settles somewhat. If a copper min
eral, the liquid will have a deep blue
color. Nickel solutions similarly
treated become blue, which, how
ever, is fainter than the color pro-
duced by copper, and in any event
the, ores OF nickel are apparently not
widely distributed. There are many
other tests for copper, but the two
described require little time, knowl-
edge or skill and are as good as any
for. practical purposes.vGordon
Sur, in Mining World.