|TREATMENT / ENHANCEMENT
Precious topaz is usually, but not always heat-treated. Blue topaz is irradiated in government approved nuclear reactors that are subject to strict NRC regulations. All major distributors of blue topaz must comply with the licensing provisions of the NRC and the state in which the material is sold. Because the blue topaz treatment and distribution is controlled by a few major suppliers who are licensed, these regulations are rarely a problem for the retailer. Blue topaz should be purchased from a reliable dealer who can provide a paper trail in order to avoid complications.
When a very thin layer of color is put on the gemstone’s surface it is called a coated topaz. These go by the trade name of “mystic topaz” or diffused topaz.
Topaz come in many colors and their origins vary according to the colors. Most yellow, yellow brown, golden, sherry, and pink varieties come from Brazil. The clear material that is irradiated to create blue topaz is also from Brazil. Some natural colored blue topaz was found in the Ukraine in 1964. But most blue topaz is irradiated from clear material.
The name topaz probably comes from the island where the gemstone was first discovered, Topazos, which later was called Zebirget, also where the first peridot was found. For a time all yellow to yellow-brown gemstones were called topaz, today this is not an acceptable practice.
Topaz is relatively hard but cleaves easily so care must be taken in setting the material or steam cleaning the gemstone. The ultrasonic should never be used.If the topaz is a “mystic topaz” or coated heat, ultrasonic, and steam should be avoided.