St. Johnsbury Caledonian. [volume] (St. Johnsbury, Vt.) 1867-1919, 1892-01-14
Correspondence of the cA1EDoN1Ax.]
GRANITE.
Something about an Important Element
of Vermont'S Industrial Life.

URANI IL.
Something about an Important EIemeu
of VermOnt'S Industrial Life.
AS granite is one of the principal
industries of St. Johnsbury and O.
Vermont, information on the subject
may be of general interest. Have
you ever examined freshly broken
granite with a magnifying glass? II
you have, you have seen a mountain
of gems of various and beautiful
colors and sizes. No showcase OF
gems equals it. We shall not be
surprised at this when we consider
the constituent parts of granite.
Common granite is composed OF
mica, feldspar and quartz Mica is
white, shading to brown and Jet
black. The white, the isinglass of
our stoves, is called Muscovite; the
black Biotite. The white is seldom
found alone in granite, but little
white is mixed with a good deal of
the black, and such granite is called
Muscovite-Biotite. This is the prin-
cipal granite of Vermont and New
Hampshire.
Feldspar, the mineral of which
crockery is made, is of white, red and
blush color, of pearly lustre and
crystalizes in various forms, often
radiating from delicate line
through the centre, forming the noted
twin crystals so common in New
Hampshire, sample of which is in
the Museum. Feldspar usually con-
stitutes the greater part of granite.
Quartz, the mineral from which
glass is made, is CLASSY crystalline
substance of various colors, colorless.
transparent, milky white, rose,
smoky, sometimes blush violet.
yellowish and dark. In granite
these three minerals are mixed in
varying proportions, and beautifully
crystalized as only God in the great
laboratory of nature could mix and
crystalize them. No wonder that a
mountain of gems is revealed to us
by the magnifying glass.
Besides these three minerals some
times hornblende. dark brown or
greenish mineral, takes the place Of
biotite and forms what is called
syenite from ancient Syene in Egypt,
where this kind of granite was
quarried for obelisks. Some authori-
ties restrict syenite to feldspar Tor
thoclase) and hornblende, but the
Egyptian syenite contained quartz
and so do most of the American.
The feldspar in the Egyptian syenite
was red or flesh colored and this is
the more common color, but grayish
and whitish varieties occur. The
Scotch and Quincy GRANTEES are
syenites. Granite is something strait
fed in dark and light layers and
splits easily along theselayers. This
is called gneiss and is sometimes
used for building purposes. Granite
and gneiss often run into each other
SO that it is not always easy to dis
tinguish one from the other. All
granite is granular, hence its name.
There is evidence that granite was
once in fluid state. Recently in the
Carrick Bros yard a block of Barre
granite was split open and inside
was another stone of different color
and material which evidently the
granite when in a liquid state had
gathered up and afterwards harden
ed around it. In most cases such
stones have probably been fused by
the intense heat and mixed with the
general mass, but in this case and a
few similar ones the fluid mass had
become so far cooled that it did not
fuse the stone, but hardened around
it. In Craftsbury is granite,
variously called nodular, concretion-
airy and pudding, that abounds in