(I assume you were replying to my Wolverine image.)
Adamantium Wikipedia entry. Basically in the Marvel X-Men definition: "In its solid form, It is near-impossible to destroy or fracture in this state, and when molded to a sharp edge, can penetrate most lesser materials with minimal force."
Excerpt:
Adamantium is a fictional metal alloy, most famously appearing in American comic books published by Marvel Comics. It is best known as the substance bonded to the character Wolverine's skeleton and claws.