Bismuth Crystals.
https://en.wikipedia.org/wiki/Bismuth
It has a half-life more than a billion times the estimated age of the universe. So not very radioactive.
My mom drove me around in one of those. Later, the trouble of setting it up was bothersome, so I just stood up on the seat. If mom hit the brakes hard her right arm came out to brace me. Even 40 years later if she hit the brakes, be ready to get whacked with her right arm coming over as an automatic reflex.
Women washing clothes next to a wooden water tank in Texas, 1910.
