Because many green diamonds obtain their color from exposure to radiation in a laboratory (a process known as irradiation), there have been concerns about their safety when used in jewelry.

All companies in the United States that apply radiation treatments to any type of gemstone must be licensed by the Nuclear Regulatory Commission. These companies must use approved methods to treat the gemstones, then store them in a secure facility until their radioactivity declines below a level that would make them safe for use in jewelry. Only then can they be released for jewelry manufacturing or sale to the public.

The process of gemstone irradiation is very common. Almost all of the blue topaz offered in stores today is colorless topaz that has been irradiated and then heated to produce a blue color. “Swiss blue” and “London blue” are trade names for two of the most common varieties of treated blue topaz seen in today’s market.

Gemstones have been treated by irradiation in the United States for decades with the Nuclear Regulatory Commission actively licensing companies who do the treatments. Based upon their experience the NRC reports:

The NRC has no reason to believe that wearing irradiated gemstones can be harmful. There have been no reported cases of anyone being harmed by wearing them. There is no safety reason to stop wearing blue topaz or any other irradiated gems.