Stones have been worn by both women and men since prehistoric times. Just as in the jewelry of modern times, beautiful stones, rare and colorful, are most often the dominant feature of a piece with a metallic setting for ornamentation.
The stones used in the crafting of fine jewelry are generally divided into two classes- precious stones and semi-precious stones.
These terms are used heavily in the commercial world of jewelry when considering variety and value. While artistic merits are only a matter of opinion, the value of a stone is what it will bring in the marketplace. It should also be mentioned that many people, collectors and general consumers alike, prefer the rare to the beautiful.
These stones are simply rocks (minerals) taken from the earth, and after they have been enhanced by the artisans cutting and polishing, the finest and rarest of them are what we call gems.
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.
A large number of stones used in jewelry are known as semi-precious; the most important ones are as follow: amethyst, lapis-lazuli, turquoise, aquamarine, topaz, moonstone, peridot, opal, tourmaline, zircon, chrysoberyl, alexandrite. Others of less importance although much used are: chrysoprase, jade, garnet, agate, azurite, malachite, bloodstone, coral, carnelian and many others. These stones while comparatively common and inexpensive are indispensable to the worker in jewelry. The variety of colors to be had in these stones make it possible to produce unusual designs of artistic merit and to adapt them to the personality and costume of the wearer. For more detailed information regarding gem stones the reader is referred to "Gem Stones" by G.F. Herbert Smith, also "The Curious Lore of Precious Stones," by George Frederick Kunz.