The Republican. [volume] (Oakland, Md.) 1877-current, 1883-03-03
Garnets.


The color of the garnet is blood or
cherry red; when mixed with blue it
passes into crimson and violet red, and
when tinged with yellow into hyacinth
red; it is also met with of reddish
brown color, liver-brown and black.
also greenish black. 1t occurs in masS
disseminated, in angular fragments, or
crystallized. Its primitive figure is the
rhomboidal dodecahedron, which, when
somewhat heightened, presents the APP
pearance of short six-sided prism, the
faces of which are parallelograms termi-
mated by trihedral submits with rhom-
boidal faces. Sometimes the original
faces of the dodecahedron entirely dis
appear, and the result is solid bounded
by twenty-four equal and similar trapezi-
ums. Sometimes all the sides of the
primitive dodecahedron are replaced by
heightened hexagons, whence results a
solid bounded by twelve rombs and
twenty-four hexagons. Other more COM
plicated figures, but which cannot be
rendered Ineligible by mere description,
originate from the mixture of the two
preceding notifications. The size of
the crystals is subject to great variations.
Some are no larger than a pins head,
while others are four inches or more in
diameter. The external luster is casual,
but generally glistening; the internal
luster is right-shining, vitreous. Its
fracture is perfectly conchoidal, passing
into imperfectly conchoidal, coarse
grained, uneven or splintery. It's frag-
ments are unfortunately angular and
sharp-edged. IL sometimes occurs in
granular or lamellar distinct concretions.
1t varies from transparent to translucent
on the edges. Its hardness is superior
to that of quartz. Its specific gravity is
from 81 to Az.
1t is often magnetic, and is fusible
without much difficulty before the blow
pipe into black enamel. When strongly
heated in a charcoal crucible, it affords
gray dusky glass full of grains of iron,
often amounting to ten or twelve per
cent.
The mineral has been repeatedly an
alyzed by Klaproth, Vauquelin, and
other able chemists, but without much
agreement in the results; and as in gen
eral the same method of analysis has
been adopted, the remarkable differences
which have occurred can only be at
tributed to real variation in its COM
positions; they all agree, however, that
it contains large proportion of iron,
and possibly this ingredient may be the
one which principally influences its crys-
utilization.
The Bohemian garnet has been an
alyzed by Kaproth, with the following
results: Oxide of iron, 1915; oxide of
manganese, OBS; slick, 40; alumina,
2.S5; lime, 3.5; and magnesia, 10.
Vauquelin's analysis of the same stone
gives the following: Oxide of iron, Al;
slick, Sc; alumina, 80; and lime, 3. The
Sirian garnet, according to Klaproth,
contains: Oxide of iron, Sc; oxide of
manganese, OBS; slick, 1915; and
alumina, 27.25. The most beautiful and
valuable garnets are the oriental. They
come principally from Pegu; and the
town of Sirian having been formerly
the chief mart for them, they are hence
by corruption known among lapidaries
by the appellation of Syrian garnets.
They appear to be the carbuncle of the
ancients; their color is crimson, verging
into very red violet; they are trans
parent, and have a conchoidal fracture.
Of their geological situation we are en-
tirely ignorant
Next in estimation to the oriental is the
Bohemian garnet. 1t is met with in the
Mittelgebirge of Bohemia and in Saxony;
its color is blood red, verging into yellow;
it never occurs crystallzed, but only in
rounded and angular grains; it is trans
parent. and its fracture is conchoidal.
1t occurs in floetz-trap and in alluvial
land, formed by the decomposition of
this class of mountains; it is also met
with in serpentine.
Common garnet occurs almost always
in primitive rock, especially in mcaceous
schistus, chloritic slate, and serpentine;
it is sometimes so abundant as to consti-
tute the principal part of the rocky mass
in which it is found, which is then an
excellent fiux for iron ores ON account OF
its fusibility and the large quantity OF
this metal which it contains.
The oriental and Bohemian garnets
when cut and polished are very beauti-
full, and were formerly particularly the
first in high estimation, but by the
caprice of fashion their employment
and consequently their value, have since
much declined. GLASSWARE Reporter.