M. D. ROTHSCHILD.
41 and 43 Maiden Lane,
New York.
HAND-BOOK OF PRECIOUS
STONES.
What are Precious Stones?
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 lustre, 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. To-day, 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.