Humm Blue Topaz... heated... Are you sure?
Just be careful (I don't want to scare you, but)
"Swiss" blue topaz are treated in a nuclear reactor... but they shouldn't be radioactive... they say (I still would like to check with a geiger counter).
"Due to residual radioactivity, the irradiated topaz must be held in a secure facility for a specified period of time before it can be released for heating, cutting and polishing. The time varies from a few weeks for topaz irradiated in a linear accelerator to a few years for topaz irradiated in a nuclear reactor. There are very strict rules in place to protect not only consumers but also the cutters and gem dealers who handle these gems on a daily basis."