River Falls journal. [volume] (River Falls, Pierce County, Wis.) 1872-2019, 1890-02-06
GEOLOGICAL MYSTERIES.
Supposed Origin of Some of the Precious
Stones of Commerce.

Supposed Origin of Some of the Precious
Stones of Commerce.
Geology has been a revelation to man.
kind and has told us wonderful things of
the past history of the earth. But
geology has secrets of its own that are
as hidden from comprehension as the
atmosphere of the moon or the belts of
Saturn. Certain things have been done,
says the geologist, through volcanic
jtion or the agency of fire, and that is
As near as he can come to it. So that,
after all, we see effects, but know little
or nothing of causes. There is rock
uown as amygdaloid, one of the
ig. eous rocks, which in some of the
gigantic transformations of nature, we
will say in cooling from a melted
state, formed within itself cavities
from the size of marble or bead to
that of the closed hand. Now, as nat
ure abhors a vacuum, she set to work
to fill these cavities, and in doing so
she used other materials, and these
combinations produced some of what
we call the precious stones of COM
merce." Exactly how this was done we
can not tell, but we see some hint of the
operation in every subterranedn cave
where stalactites and stalagmites
are found. Every student knows that
this is the result of dropping water
which contains carbonate of lime. The
water evaporating leaves minute par
ticle of lime, which takes something to
itself from the earth or atmosphere, and
in the course of ages bodies are formed
of a most remarkable character. In
probably somewhat the same fashion
have these cavities been filed in the
igneous rocks, and then come time and
storms and other Misunderstanding
perhaps-and the rocks are sent apart,
and out drops a bead or a bowlder, and
a curious man picks it up, and hammers
and breaks it. and then he puts polish
on it by some process more or less adj
vanced, and lol he holds in his hand an
agate or an onyx.
Many of the stones used in the arts
have no other origin, and are deposits
of silica, alumina, oxide of iron and
other coloring substances. 1t is the
color or arrangement of colors that
gives the name, and thus we have agate,
ONYX, chalcedony, carnelian. sard, chrys-
oprase, sardonyx and others, all mem
bers of the quartz family and all hav-
ing a family resemblance. The agate
has veins of different shades Of color in
parallel lines. Sometimes those are
very close together. as many as fifty to
the inch, but this is unusual When
there are alternate bands of color and
a transparent medium we have the
onyx; but the latter may be obtained by
cutting the stone in different way.
Agates are used chiefly for ornamental
purposes. such as cups. seals, rings,
handles for parasols, swords, table and
mantel ornaments, but the material is
so hard that it can only be worked by
those who have practiced skill. The
onyx was valued by the ancients fc, its
application to canoes and intaglios- the
first an object in relief, the latter a cut
in" process; and these objects are still
made. Nature produces some very
strange forms occasionally, and agates
are found with exact resemblances of
moss and other natural objects and
figures, which are very curious and often
very aluable.-American Analyst.