practically absent on a commercial scale. Of other precious and
semi-precious gem stones produced in the United States, the principal
ones are quartz, tourmaline, and turquoise.

On the other hand, the United States absorbs by purchase over half of
the world's production of precious stones. It is estimated roughly that
there are now in the United States nearly one billion dollars' worth of
diamonds, or over one-half of the world's accumulated stock, and
probably the proportions for the other stones are not far different.

Value attaches to a precious stone because of its qualities of beauty,
coupled with endurance and rarity, or because of some combination of
these features which has caught the popular fancy. No one of these
qualities is sufficient to make a stone highly prized; neither does the
possession of all of them insure value. Some beautiful and enduring
stones are so rare that they are known only to collectors and have no
standard market value. Others fail to catch the popular fancy for
reasons not obvious to the layman. While the intrinsic qualities go far
in determining the desirability of a stone, it is clear that whim and
chance have been no small factors in determining the demand or lack of
demand for some stones. As in other minerals, value has both its
intrinsic and extrinsic elements.

For the leading precious stones above named, the values are more nearly
standard throughout the world than for any other minerals, with the
exception of gold and possibly platinum. Highly prized everywhere and
easily transported, the price levels show comparatively little variation
over the world when allowance is made for exchange and taxes. The
valuation of precious stones is a highly specialized art, involving the
appraisal not only of intrinsic qualities, but of the appeal which the
stone will make to the buying public. In marking a sale price for some
exceptional stone not commonly handled in the trade, experts in
different parts of the world often reach an almost uncanny uniformity of
opinion.

It is estimated that the world stock of precious stones approximates
three billion dollars, or a third of the world's monetary gold reserve.
Because of small bulk and standard value, this wealth may be easily
secreted, carried, and exchanged. When the economic fabric of
civilization is disturbed by war or other conditions, precious stones
become a medium of transfer and exchange of wealth of no inconsiderable
importance.