olished surfaces of which show that the granite is made of
small bits of different coloured minerals, cemented together into solid
rock. Outside the gate you will usually find a place where monuments and
gravestones may be bought. Here there is usually a stonecutter chipping
away on a block with his graving tools. He is a man worth knowing, and
because his work is rather monotonous he will probably be glad to talk
to a chance visitor and answer questions about the different kinds of
stone on which he works.

There are bits of granite lying about on the ground. If you have a
hand-glass of low power, such as the botany class uses to examine the
parts of flowers, it will be interesting to look through it and see the
magnified surface of a flake of broken granite. Here are bits of glassy
quartz, clear and sparkling in the sun. Black and white may be all the
colours you make out in this specimen, or it may be that you see specks
of pink, dark green, gray, and smoky brown, all cemented together with
no spaces that are not filled. The particles of quartz are of various
colours, and are very hard. They scratch glass, and you cannot scratch
them with the steel point of your knife, as you can scratch the other
minerals associated with the grains of quartz.

Granite is made of quartz, feldspar, and mica, sometimes with added
particles of hornblende. Feldspar particles have as wide a range of
colour as quartz, but it is easy to tell the two apart. A knife will
scratch feldspar, as it is not so hard as quartz. The crystals of
feldspar have smooth faces, while quartz breaks with a rough surface as
glass does. Feldspar loses its glassy lustre when exposed to the
weather, and becomes dull, with the soft lustre of pearl.

Mica may be clear and glassy, and it ranges in colour from transparency
through various shades of brown to black. It has the peculiarity of
splitting into thin, leaf-like, flexible sheets, so it is easy to find
out which particles in a piece of granite are mica. One has only to use
one's pocket knife with a little care. Hornblende is a dark mineral
which contains considerable iron. It is found in lavas and granites,
where it easily decays by the rusting of the iron. It is not unusual to
see a rough granite boulder streaked with dark red rust from this cause.

The crumbling of granite is constantly going on as a result of the
exposure of its four mineral elements to the air. Quartz is the most
stable and resistant to