A rare metallic element (S No. 68/1, Jan/Feb 1951: â€œThe Six Elements of Crime!â€; and others) that is discovered by Superman in July-August 1949 and named in his honor by the members of The Super-Saved Club. Superman refers to it as â€œthe hardest substance in existenceâ€ (WF No. 41, Jul/Aug 1949: â€œThe Discovery of Supermanium!â€) and as â€œmy invulnerable new elementâ€ (S No. 68/1, Jan/Feb 1951: â€œThe Six Elements of Crime!â€), and the texts describe it as â€œthe strongest metal knownâ€ (Act No. 289, Jun 1962: â€œThe Super-Practical Joker!â€) and as â€œthe strongest metal known to scienceâ€ (S No. 167, Feb 1964: â€œThe Team of Luthor and Brainiac!â€ pts. I-III: â€The Deadly Duo!â€; â€œThe Downfall of Superman!â€; â€œThe Hour of Kandorâ€™s Vengeance!â€).
In July-August 1949, after an â€œeminent chemistâ€ has reported the probable existence of a â€œsuper-hardâ€ element, as yet undiscovered, whose unique properties would make it â€œextremely valuable for all sorts of industrial purposes,â€ the members of the Super-Saved Club, acting at the urging of James Harvey Thorben, decide to pool their financial resources and scientific and engineering expertise in order to locate and refine the new element. If successful, they plan to name it â€œsupermaniumâ€ as a surprise tribute to Superman.
Officially, it is the members of the Super-Saved Club who locate the new element in a remote mountain region and refine the worldâ€™s first sample of supermaniam ore. In actuality, however, it is Superman, working behind the scenes with his superpowers so as not to spoil the club membersâ€™ surprise for him, who locates the vein of supermanium ore and refines it, for the new substance is so unbelievably super-hard that it literally shatters the machinery with which the club members attempt to grind it, forcing Superman â€œto apply his full colossal strengthâ€ in order to refine the ore by hand. â€œHeat and pressure,â€ thinks Superman as he bends to the task, â€œâ€¦ I can supply more of them with my hands than any machine can!â€
Having secretly refined the rare ore himself while contriving to make it appear that the Super-Saved Clubâ€™s machinery has somehow done the job for them, Superman graciously allows the clubâ€™s members to present him with the element they have named in his honor, promising that he will see to it that it is put to work in a multitude of ways â€œto save human drudgery!â€ (WF No.41: â€œThe Discovery of Supermanium!â€).
In January-February 1951, Superman fashions a vault out of supermanium for Metropolisâ€™s â€œfamous radium instituteâ€ in order to prevent its priceless radium stockpile from being stolen by Lex Luthor. He also makes the bars of Luthor's cell out of supermanium so he can't use his scientific genius to escape. (S No. 68/i: â€œThe Six Elements of Crime!â€)
In June 1962, Superman employs invisibly fine wires fashioned out of supermaniurn to enable him to manipulate gigantic replicas of mythical monsters as though they were colossal marionettes (Act No. 289: â€œThe Super-Practical Joker!â€).
In February 1964, when Lex Luthor arrives on the â€œprison planetâ€ Kronis to liberate Brainiac, he finds the notorious space villain locked in a â€œmighty cageâ€, fashioned by Superman from â€œan isotope of supermaniumâ€, which his powerful â€œatomic torchâ€ cannot even scratch. It is while Lex Luthor is attempting to free him from his supermanium prison that Brainiac remarks, incorrectly, that supermaniurn â€œis named after Superman because it was forged by him from the heart of a mighty star!â€ (S No. 167: â€œThe Team of Luthor and Brainiac!â€ pts. I-IIIâ€”â€The Deadly Duo!â€; â€œThe Downfall of Superman!â€; â€œThe Hour of Kandorâ€™s Vengeance!â€).