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.