the
importance of durability, which must claim the second place ; and the
desirability of a certain degree of rarity, especially where the
quality of durability may not exist in the highest degree. How far a
very beautiful and hard mineral would maintain its position as a
precious stone in the event of its becoming exceedingly abundant, one
cannot venture to judge ; but as we have to deal with existing facts
only, the problem is one which practically has not yet been presented
for solution.
As
precious stones have just to be looked at and worn, or used in
decorative work, it will be readily understood why no occult property
is of much moment in determining their value. Individual and learned
amateurs may indeed value a stone according to what they know of its
history, its romance, its memories-, or the curiousness of its
components ; but in ninety-nine cases in a hundred any enĀhancement of
value through such causes is out of the question. Still, from the
mineralogical and chemical points of view, it is perhaps legitimate to
import some elements of interest when apĀpraising the right of a stone
to be called precious, or its place in the list of gems. One need not
follow those writers who speak of precious, semi-precious, and common
stones ; but one may reasonably arrange the different kinds in a few
groups or classes, according to what we may call the average sum of
their merits. To assign a precise place to each species is not
possible. Hence the futility of such a classification as that published
in 1860 by K. E. Kluge wherein emerald takes lower rank than zircon,
and precious opal comes after garnet, while to turquoise is assigned a
place beneath nine other stones only one of which (peridot) is even
known to dealers in precious stones, and to the purchasers of jewels.