Azotic topaz is a color-enhanced variety of colorless topaz. It is named after the company that invented the unique patented coating enhancement treatment, AzoticÃ. Azotic topaz obtains its unique rainbow-like colors through an extremely thin metallic coating of film deposition that reflects light in a variety of colors and interesting patterns. Topaz is historically one of the most important gemstones available. It has a relatively high refractive index and a hardness level of 8 on the Mohs scale. It is a particularly popular gemstone for jewelers, mostly due to its extreme versatility and durability. It has no special sensitivity to chemicals, other than hot sulphuric acid, and it is popularly used for every type of jewelry application and design. Azotic topaz displays a stunning rainbow-like color pattern and effect. It is very similar and often confused with mystic topaz and mystic quartz, which are also coated varieties of colorless topaz. Azotic topaz is typically lighter than mystic topaz and can usually be distinguished by its brighter colors. The color, brilliance and clarity of the final product depends very much on the quality, cut and polish of the original colorless or white topaz gemstone.