I've read several articles lately saying that the Nuclear Regulatory Commission is reviewing their policy concerning irradiated gemstones. Many gemstones, including topaz is commonly irradiated to change or improve its color. Almost all blue topaz has been irradiated (and heated). If done properly, the irradiated stones should pose no threat to people wearing them. There are apparently laws in place to regulate the import of all radioactive materials. The problem seems to be that the NRC has no provisions for overseeing irradiated gemstone imports. So for the time being, they are not enforcing the laws, but are now looking into setting up some procedures and oversite. They don't believe there is any real danger to the public, but from people I've talked to there is at least the possibility that gemstones could come into the country that are still giving off radiation. Let me know if you have any more information on this topic.