Bismuth Element Number 83 Bi 

I made these crystals from pure Bismuth metal, this was probably the twentieth time I remelt the metal before getting these results. It is very satisfying to make these, but takes practice, and patients. 

Polonium Element Number 84 Po 

This electrode from a 1940's spark plug once had Polonium doping. The sales pitch was radioactive spark plugs were better for performance.Polonium has a half life of 138 days with alpha decay.  This was a short lived gimmick, as they were no better than ordinary plugs, and also were radioactive.

 Here is the packaging from 1945. The Polonium coating on these spark plugs has long alpha decay to Lead206 stable isotope.