Powerstone

“An ancient gem” from “another planet” whose weird “scientific properties” confer virtually “infinite power” on whoever possesses it. Superman and Lex Luthor battle for possession of the Powerstone in 1942 (Act No. 47, Apr 1942: “Powerstone”) and (S No. 17, Jul/Aug 1942: “When Titans Clash!”). See also: Carlyle Allerton