Clarksville weekly chronicle. (Clarksville, Tenn.) 1873-1890, 1879-07-26
which is a silicate of Alumina and

which is a Silicate of Alumina an
other bases.
Passing by the so-caIled Zeolite:
we come to two minerals of som
interest, Andalusite and Staurolite
both essentially Silicate of Alumina
The first mentioned appears unde
many varieties of form; of thes
Macle and Chiastolite "show ties
selated or cruciform structure whel
broken across and polished. Th'
structure is owing to impurities
| usually the material Of the gangue
disseminated by the powers of crys
tallization in a regular manner
along the sides, edges and diagonals
of the crystal" Staurolite (cross
stone) is SO called from the frequency
of occurrence of two crystals arrang.
ing themselves at right angles, thus
causing a very perfect cross-form.
| Numerous specimens of the vari-
Gus species of Feldspar are to be
seen, crystallized and massive. II
is quite a common mineral, gene
rally fiesh-colored or white, some
times CLASSY. 1t constitutes one OF
the essential ingredients of granite
rock, and by characteristic decom-
position which it is prone to under
go, namely the loss of its alkaline
contents, becomes the source of our
ordinary clay.
Here we come to a mineral whose
name at least suggests the idea of
ornaments Garnet which has been
long used and valued for its beauty.
Here are some representatives which
appear too black and Opaque to be
highly esteemed, and too large to
be conveniently set or worn. One
specimen, a dark colored, rough
dOdecahedron, is three inches in
diameter and quite heavy. But
along with these bulky and coarse
crystals we have some smaller,
more perfect and more transparent
ones, some Of a brownish red color
Common Garnet, some of a beauti-
full brown yellow, commonly called
Cinnamon-stone.
The Garnet is the Carbuncle of
the ancients. 1t is also supposed to
be the same as "Hyacinth."
Here too are some tourmalines, red,
green, blue and black. This mineral,
like the understanding Spar al
ready mentioned, is of most interest
in connection with the polarization
of light, although some varieties
are also highly priced as gems.
Two shelves are devoted to the |
well-knoWn substance Mica. All
from silver white to black,
large specimens and small, some
showing distinctly cut lines and |
angles of crystallization, all capable
of the characteristic division into
very thin, flexible leaves. One I'M
usual variety here noticed is of pur-
pie color, consisting of closely /
aggregated grains, known as Lepi-
dolite or Lithia-Mica.
The precious stones are always
attractive, and here are some beau
tiful crystals of Topaz, transparent
and of a delicate yellow color. By
its form it is easily distinguished
from the so-called False Topaz, to
be seen in the tray of Rock crystals,
and which is indeed only Rock
crystal colored yellow by the pres
ance of Iron. In regard to the ety.
mology of the name it may be of
to transcribe the following:
THE ancient Topazion was found
Dn an island in the Red Sea, which
was often surrounded with fog, and
therefore difficult to find. 1t was
hence named from topdzo, to seek"
This magnificent blue color, seen
lear by, belongs to the mineral
,alled Lapis Lazuli, which is used
'0r the material of costly vases and
n the construction of Mosaics. It's
powder was applied in the constitu-
ion of a most beautiful and durable
blue paint, known as Ultramarine.
This, however, is now substituted
by an artificial pigment of the same
name.
Look at this grand hexagonal
,rystal it is a Beryl from North
Carolina. 1t is between five and
;ix inches high and probably over
.hree inches acros5-a regular six
sided column, built by the crystal
izing force. Here are smaller spec
mems of the same kind; these are
Ill opaque, but in one corner of the
ray we find some beautiful trans
parent green crystals Of noble Beryl.
they are the precious stone, so val
liable in jewelry, known as Eme-
aid. It's rich green color is due to
,xide of Chromium. The finest
pecimens of this magnificent mine
al are obtained from Siberia, Hin
lostan and Brazil. One is described
IS being as large as the head of a
.alf, weighing over 18 pounds,
transparent and without a flaw.
But emitting many points of in
crest, we hasten on to say some
hing of the metals and metallic (
,re5.
"Drummers."
Many Of the large commercial
irms in the United States are dis
covering from actual experience
hat the sending out of 'drummers' ;
= H. H.