[Anno_Domini]

Spoiler!!! Click to Read!:

After you've seen Captain America: The First Avenger, it could lend to ideas that the new "element" wasn't vibranium, since Howard already knew about it, but some kind of power from the Cosmic Cube that he wanted to created his very own "element". Wether that same element was also in the Arc Reactor remains unclear, but it's a more pure power than the Arc Reactor.