Custer weekly chronicle. [volume] (Custer City, S.D.) 1890-1931, 1909-10-16


the list of accessory minerals is large.
From the Eta mine the following min.
erals are enumerated by OHarra:
Minerals from Eta Mine.
Albite. Griphite. Petalite.
Almandite. Grossularite. Quartz.
Andalusite. Heterosite. Rutile.
Apatite. Imenite. Scheelite.
Arsenopyrite. Lepidoite. Scorodite.
Autunite. Leucopyrite. Sphene.
Barite. Liebernite. Spinel,
Beryl. Lollingite. Spodumene.
Biotite. Melanite. Stannite.
Bismuth, Microcline. Tantaline.
Columbite. Molybdenite. Tourmaline
Corundum. Monazite. Triphyllite.
Cupro-cassiterite Muscovite. Triplite.
Epidote. Olivenite. Wolframite.
Galena. Orthoclase. Zircon.
Graphite.
Chalcocite, apparently original, was
collected by the writer from this dixie
in September, 1908.
The absence from these dikes of some
minerals that generally accompany cas-,
siterite is very noticeable. No topaz OF
axinite are known, and no fourspar was
seen by the writer. There is very little
chaIcopyrite or pyrite in the dikes.
TUNGSTEN.
Tungsten ore is not known to have
been produced commercially in the
Black Hills except at Lead, though near
Hill City a considerable number oi
tungsten-bearinS veins and dikes have
been discovered and large amount Of
prospecting has been done. In this re,
gion wolframite is the tungsten ore oi
economic importance. Scheelite occurs
sparingly, in some places as an original
mineral and in others as an alteration
product of wolframite. In the vicinity
of Hill City the mineral is found in peg
Matte dikes and in quartz veins which
are probably later product of the same
igneous phenomena that caused the
dikes. Wolframite is not known to be
present in any considerable quantity in
the pegmatites which carry cassiterite
and in fact it is known in only couple
of places in the dikes in quantity suffi
ciently large to encourage prospecting
In the quartz veins, however wolframite
and light-gray cassiterite are intimately
associated.
Wolfram Claims.
Three miles east of Oreville, on the
west flank of Harney Peak, A. J. Reu.
chel, ]. ]. Sharp, and c. H. Cummings
have four claims located on coarse peg
MATTE dikes. At the upper end of the
claims dixie in which wolframite has
been found stands 80 to 40 feet above
the surface, with strike of N. 5 degrees
w. 1t is apparently vertical and 20 to
80 feet thick. On the south end of this
prominent outcrop some wolframite
occurs in irregular punches an inch and
more in thickness through a shoot not
oyer 2 feet wide. At this place the peg
Matte is composed of coarse feldspal
and quartz with smaller lunches o1
muscovite. The claim which appeared
to be the best of the four at the time
visited is located below northwest of
this place, at the junction of the dixie
just described with a second striking
N. 40 degrees w. At the junction the
dikes are only few feet wide, but they
gradually widen as they separate anG
100 feet away the second dixie is as wide
as the first.
The exposures we're not good, but in
the first dyke few feet from the juno
ton wolframite occurred as thin plates
~ inches wide by one sixteenth of ar
inch thick, interleaved with muscovits
mica, and in coarser pieces in feldspal
and in quartz, as we'll as in mixtures o
the two. The equalization is very i'm
perfect and evidently was contempora