Element 152
From superman.nu: Supermanica
Element 152
A combination of gold, silver, and iron -- Element 152 has anti-gravity properties. Created by Mon-El (Adv No. 305, Feb 1963: "The Secret of the Mystery Legionnaire!") as part of his Legion of Super-Heroes try-out and after his his exile in the Phantom Zone (an idea of Superboy's to suspend his vulnerabilty to lead) is over. The element is later refined by Brainiac 5 for the creation of the Legion flight rings.
