PRECIOUS STONES. 79
One
of the chief difficulties to overcome in the synthetical preparation of
a mineral is crystallisation. Nearly all minerals crystallise in some
form, and more particularly is this so with precious stones, excepting
the Opal and Turquoise. Now Nature has one great advantage over our
puny experiments in the laboratory: she can take unlimited time and has
great stores of energy at her command, enormous pressures and high
temperatures working together or independently. In the laboratory, on
the other hand, pressure and temperature, although obtainable, are in
many cases not sufficiently high, and also not easily controlled. Then,
again, as regards time, poor man does not live long enough. Working
under conditions such as these Nature need have little fear of being
ousted from the Diamond market. Whatever method we may adopt in our
experiments, time will not wait, and crystals of fair size and shape
are not made in five minutes, so the result is, generally speaking, a
few microscopic splinters hardly worth looking at. If sufficient time
could be given in many of the experiments carried out, for
crystallisation to take place slowly, then one of the chief
difficulties would be overcome.
Even
presuming we knew definitely how some precious stones were formed in
Nature's laboratory, it is doubtful whether we could apply Nature's
methods in our laboratories to produce similar results. Many have been
the theories put forward to explain the origin of that monarch of
precious stones—the Diamond, one in some cases being as feasible as
another ; but at the present day it is difficult to apply any one of
them as correct. To chemists and physicists, from early times, this
stone has been the subject
