Captain America's shield is made of Proto-Adamantium, a composition of Vibranium, steel, and an unknown catalyst. Since Proto-Adamantium could not be replicated, it led to the creation of True ...

Though adamantium is seen as less versatile, it is considered the stronger of the two super-metals, and Cap’s proto-adamantium shield is one of the most resilient weapons in the Marvel universe.

The power of the Adamantine went to sleep as the ages of the gods ended, and eventually, humanity created its own version of the Adamantine: adamantium. Adamantium was near-impregnable ...