A parcel of 100 stones of deep blue irradiated topaz, imported from Brazil, was found to be radioactive at a level somewhat higher than typical background activity. Analysis indicates that the material had been treated by neutrons in a nuclear reactor. Most irradiated topaz in the trade is not radioactive. Nevertheless, routine testing for radioactivity in topaz, beryl, green diamonds, red tourmaline, and possibly all gemstones may be advisable for the protection of the jeweler. -- AATA