The republic. [volume] (Washington [D.C.]) 1849-1853, 1849-10-15
Analysis OF California GOId-Paris Academy
OF Sciences.

oi an analysis Oh the Soluen spahSles OF
sands of California, by M. Dufrenoy, read
before the Paris Academy. Its publica-
ton may afford useful hints to miners and
others.
M. Dufrenoy read an interesting com
munIcauon on the results he had obtained
from careful comparative investigation
OF the golden sands of California, New
Granada and the Ural.
The French Consul at Monterey having
forwarded to the Minister for Foreign AZ
fairs collection of specimens of the gold
of California, aportion of these specimens
were sent to the "Ecole DIES Mines and
these ! had an opportunity of examining.
They are composed
|. OF two specimens OF auriferous earth,
collected at the surface of the soil, on two
points of the valley of the Sacramento.
.. OF auriferous sand, resulting from
careful washings of the preceding earths,
and in which spangles of gold were OBJ
served.
3. Pebbles of quartz and fragments of
rock collected in the alluvium of which
this valley is composed
4. Two fragments of gold and
5. Spangles of gold brought from three
different points of the Sacramento, name
ly: from the American river, near its con-
iluence with the Sacramento from the
same river, at about thirty miles from its
mouth; and from the Pen river, distance
of about forty to fifty miles eastward of
the former. These three points included
nearly fifth part Of the valley of the Sa-
cramento, which takes its rise in the Sierra
Nevada, Snowy Mountains and empties
itself into the ocean at the port of San
Francisco. Its course is nearly from east
to west, about 2lO to 220 miles in length.
The spangles Of California gold are much
larger than those which come from the
washings of the Ural or those of Brazil.
They also differ in their reddish color,
which causes them to be distinguished at
first sight. Their composition, according
to the analysis made by M. Rivot, is
Gold 90.70 Iron OBS
Silver $50 -
Otal w. ~
The soils of the Sacramento valley are
light; to the touch they appear soft enough,
but, on rubbing, few particles of hard
substance are felt The color is light
brown; the microscope shows them to be
almost entirely silicious; the little frag-
ments of which they are composed are an
gular and transparent; they easily agglo-
merate together; resemble, in their color
and transparency, a saline mass; by the
naked eye nothing but distinct grains are
distinguished. The piece OF gold sent to
the "Ecole des Mines" weighs 47.9414
grammes, (nearly Is ounce;) it is of a
somewhat red color; its composition is
otherwise very analogous to that of the
gold spanges. This piece of gold adheres
to some white quartz, the surface of which
is worn like pebble; it must for a long
time have been subject to considerable
friction; nevertheless it has preserved its
general form, which is that of thick
vein, fiat and irregular. The form of this
piece, and the presence of quartz, reveals
to us the fact, that in the primitive beds
gold forms small veins, with a anartaze
gangue.
The schistose fragments which exist in
the valley OF the Sacramento, give reason
to think that the mountains which contain
auriferous veins consist rather of micaceous
schlst than of granite, properly so called.
This conclusion agrees also with the ex-
animation of washed auriferous sands
NATURE OF THE AURIFERoUs SANDS
OF CAi IFoRNIA.-The general tint of these
sands is black. We perceive, at first
sight, that the oxydulous iron predom-
mates, and that it is that mineral which
causes the color. ! therefore commenced
by separating the oxydulous iron by means
OF the magnet; three grammes produced
l.79 of iron, or 1892 per cent. Notwith-
standing the separation of this large pro-
portion of oxydulous iron, the sands still
retained their dark color they were very
rich in gold, and we remarked more dis
tlnctly numerous spangles.
Examined by the microscope, the sands
remaining after the separation of the iron
contained some octahedrous crystals
some with mirror-like facts, and but little
altered the others rounded, but still bril-
liant. These crystals, by their form and
the color Of their dust, appear to belong
10 utanlleTous oxydulous iron tney are
mixed with hattened crystals, which their
hexahedrous projection and their red dust
cause to be considered as olegist iron.
Lastly, among the black grains we OBJ
serve dull, irregular and soft fragments,
which have all the character of manganese.
The titaniferous oxydulous iron pre-
dominates considerably in the second por
ton of the sand, while the manganese, on
the contrary, appears but rarely. This
second species Of oxydulous iron may be
clearly distinguished from the oxydulous
iron separated by the magnet; this, which
is in dull fragments, is of rusty color in
certain parts.
Mixed with the titaniferous oxydulous
iron, we find, in the second portion of the
sands of California, many crystals of white
zircon, terminal at their two extrernities,
the shapes of which are all defined. These
are :
|. Square prisms, surmounted by an
octahedrOn with a SQUARE base placed on