The mineral to which the term ” precious stone” is applied, must
be adaptable for jewelry or ornamental purposes and must possess
beauty, hardness, and rarity.
The beauty of a precious stone or gem consists of its color or
colorlessness, brilliancy or softness of luster, and
transparency. To take a high and lasting polish, a mineral must
be hard, —and many stones that would otherwise be highly valued
are low in the estimate of worth because they do not possess of
sufficient hardness to make them endure the wear and friction to
which a precious stone is subjected when used in the form of
jewelry. The rareness of precious stones has a decided effect in
determining their values. For instance, the crocidolite,
commercially known as tiger-eye, was sold by the carat some
years ago, and was largely used in the making of fine jewelry.
Today, this material is so plentiful that it is no longer
classed among the higher gems, but serves for cameos and
intaglios like chalcedony and onyx.
The changes of fashion have much to do with determining the
market value of precious stones. Amethysts, topazes, cat’s-eyes,
aquamarines, alexandrites, and even emeralds and opals have been
eagerly sought for at times and then again neglected for other
gems, causing a sensible difference in the value of these stones.
It has been a mooted question as to the proper dividing line
between stones that deserve the title “precious,” and those,
which should be placed in a so-called semi-precious or lower
category. To draw such a line is hardly possible, as neither
hardness, rareness, nor value would be a positive test–some of
the hard stones, like zircon and almandines being less valuable
than softer opal, while the diamond, one of the most plentiful
of precious stones, is at the same time, one of the most
valuable.
Neither can price be taken as a complete test, because fashion
makes a turquoise, an opal, or an emerald much more valuable at
one time than at another, All precious minerals used for
ornamental purposes, from the diamond to quartz, or chalcedony,
may properly be termed precious stones.
The Final Word On Precious Stones
The most precious stones are the diamonds, emeralds, rubies and
sapphires. The pearl is oftentimes classed with precious stones.
Although strictly speaking while it is not a stone it holds an
esteemed place in jewelry.