The three-bladed radiation warning symbol, as we currently know it, was "doodled" out at the University of California Radiation Laboratory in Berkeley sometime in 1946 by a small group of people. This design is supposed to represent activity radiating from an atom. These trefoil earrings are cast in solid white bronze with a sterling silver plated overly. I thought it only fitting to give them a corroded surface finish enhanced through oxidation. With a diameter of one inch across, they are slightly larger that an ordinary quarter although somewhat thicker. Four piercings give them lots of depth without a lot of weight.