Heating is the process of enhancing the color of some precious gemstones such as ruby or sapphire. The treatment consists of heating the rough gemstones to a temperature of 1600 degree Centigrade, allowing internal inclusions, chemical elements, and other impurities to melt down and reform themselves so that the gemstone appears cleaner and more intense in color (or even a different color altogether). Heat treatments are considered a natural enhancement to gemstones as this process has been around for centuries and does not harm the integrity of the gemstones. Unlike some gemstone enhancements, heat treatments are irreversible. Common gemstones that undergo the heat treatment process are: sapphires, rubies, tanzanite, amethyst, aquamarine, citrine, tourmaline, and topaz, among others.
See Also: Enhancements, Glass Filled, Oiling