Gemstone (Gem) is described as precious or semiprecious stone that may be used as a jewel when cut and polished. It includes diamond, beryl, emerald, chalcedony, agate, onyx, tourmaline, chrysolite, sapphire, ruby, spinel, topaz, turquoise, zircon, cubic zirconia, jacinth, hyacinth, carbuncle, amethyst, alexandrite, cat's eye, bloodstone, hematite, jasper, moonstone, sunstone, and many others.