Cobalt 60 has a half life of 5.27 years. Assuming that a language lost to time is at least 500 years old, the rod should be fairly safe to handle. Heck, even after only 100 years less than 0.01% of the original amount of radioactive material would be left.
But that aside - One of the items that can be found in the video game series Avernum is Uranium bars, which give you a nice unhealthy glow :)