Kryptium was the hardest and most durable element on the Planet Krypton.
History
Earth-One
It was used sparingly due the difficulty of forging it. But once formed, it was unbreakable and could cleave inch-thick solid steel, a diamond, or even Superman's ultra-dense flesh.[1]
The rare element was first used by Kryptonian scientist Hab-Rull; who built a power-chamber of Kryptium to contain his super-nuclear power generator. Jor-El, accompanied by a young Kal-El, warned Hab that even Kryptium was not enough to control the energies that he would unleash; and not for the last time, Jor-El was ignored and disaster followed.[1]
Hab-Rull was right that the Kryptium power chamber would contain the majority of the blast, but the chamber itself and its contents were blown out of Krypton's orbit and onto a trajectory that lead directly to Earth. Because the Kryptium left Krypton before the cataclysm, it was not exposed to the blast's shock waves and thus was not transmuted into Green Kryptonite.[2]
On Earth, a petty gadget-based adversary of Kal-El named Jon Smatten found the meteoric remains of Hab-Rull's lab while hunting for Green Kryptonite. The blast shielding provided by the Kryptium was so resilient that — despite being blown light years from Krypton — the lab itself was almost intact; complete with Hab-Rull's notebooks and the De-Coherer; which Smatten learned how to use. He formed the Kryptium into an indestructible robotic suit of armour as well as the holy grail of weaponry, the Super-Sword of Krypton.[1]
Characteristics
250
Kryptium as a non-ductile metal, with a hardness exceeding that of diamond and a tensile strength exceeding any earthly metal such as Maraging steel. The material is otherwise unworkable and unbreakable, but for the De-Coherer Ray — a device whose secrets died with Krypton — which could cut or shape it.[2]
Unlike many other materials from Krypton, Kryptium's supreme durability was not affected by the particular quality of the local sun's light. Thus on Earth, or under the red light of Rao; Kryptium was adamantine.
Notes
- The Kryptium sword was seen once more in Action Comics #333, where a crook brandished it briefly at Superman.