The Wallace miner. [volume] (Wallace, Idaho) 1907-current, 1916-08-03

Texas, and in eruptiye rocks as III
/ Nevada.
The prospector is particularly inter-
ested in finding ores of tungsten at
this time. The principal tungsten
minerals are wolframite, manganese
iron tungstate; hubernite, manganese
tungstate; ferberite, iron tungstate;
and scheelite, calcium tungstate. The
first three minerals are grayish 10
brownish black. The last is white,
yellowish, brownish, or sometimes
grayish like blush quartz. The gen
eral appearance of scheelite is that OF
feldspar. 1t usually presents numer-
Gus glistening faces. due to cleavage,
which is absent in quartz. All of the
tungsten minerals are noticeably
heavy, and for this reason alone are
likely to attract attention, If found in
pieces the size of a walnut or larger.
OF course, handful of small pieces
will have the same unusual weight
when their mass Is considered. Small
pieces, though of the same gravity as
larger ones, may fail to attract at
tention to this property of their re-
markable density. Where tungsten ore
occurs in disseminated grains 1t Is
found in masses of considerable size.
| To determine the presence of the tung-
stem minerals the prospector can apply
the same methods he uses to prospect
for gold; that is, by pulverizing the
rock and panning. The concentrate
| then can be tested easily. Tungsten
ores are generally found in highly
silicious rocks, such as granite gran
itoid schist, in rhyolite at and near
| the contact of limestone and granite
rocks. Tungsten minerals also occur
| in pegmatite veins, as in some of the
New England states, and in the Black
hills The most profitable tungsten
mines in the Black hills, however, are
found associated with the sedimentary
formation near the base of the Cam
brian, where quantities. and limestones
appear to replace the latter. The min
erals are frequently associated in veins
with the ores of gold silver, lead, cop
per and zinc, though sometimes they
are scattered through the country
rocks.
When the rock suspected of con-
tanning tungsten has been pulverized
and concentrated by panning, the con-
centrate may then be tested in sim
pie manner. Place the concentrate in
test tube, drinking glass, or even
in an ordinary tea cup. Add a little
hydrochloric acid; if tungsten be pre-
sent, yellow powder will form at the
bottom of the glass, though this may
be discolored somewhat by the pre-
sence of iron minerals. Add to this
solution little metallic zinc and the
solution will turn blue if tungsten be
present, the depth of the color being
determined by the quantity of the yell
low powder. If only little the color
will be light blue. If the amount is
considerable, the color wiz be darker,
even to deep indigo blue. The addi-
ton of tin in place of zinc to the So
luton has a similar effect, producing
the blue color. The prospector may
have neither pure zinc nor tin, in
which case he may substitute a piece
of tin foil, or even scrape little tin
from a bright tin can, or chip off a
little piece of solder Either of these
as zinc or tin.
When zinc is added to the solution
containing the yellow powder, the
color will be first blue; then port
wine color; then brown, but if the re-
duction takes place quickly as it may
with scheelite, the blue color may not
be observed at all, the first color seen
being a reddish lilac, which quickly be-
comes brown. If tin be used instead
of zinc, the first color is blue then
lilac, then port wine color when slow
ly turns to brown. When using this
test, allow the solution to stand sew.
eral minutes after boiling, before adj
ding the zinc or tim in order that the
formation of the yellow powder (the
tri-oxide Of tungsten) may be com
plete.
Sulphuric acid, one patt acid TO
two or three parts water, may be used |
in place of hydrochloric acid with the
same results, but the reactions will be
slower. Nitric acid also will give the !
yellow powder, but no blue color Is |
obtained by the addition of tin or zinc. |
Wolframite must be boiled muon long
err than scheelite, sometimes 10 to 20 |
Failure to give it ;lenty al |
time may result in no reaction BENT
evident.
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