Gavantium is an alloy comprised of an element known as gavant along with iron, and carbon. When forged together, the three of them form an almost impenetrable barrier, able to withstand the force of any Godsend. 

The element of gavant itself is a relatively new one, only being discovered in the 2100’s, after huge deposits were found underneath central Australia during the Age of Anarchy. The northern borders of Australia had been occupied by Japan at this point, and central Australia was as it is now, a total off-limits zone due to bio-hazards. But during this expansion into Australia, the Japanese came across huge nodes of an element never discovered before, which was named gavant. Upon many decades of research, it was found that gavant and steel mixed in such a way that it created an impenetrable alloy.

This alloy could be treated in a variety of ways, from changing heat, pressure, and alloy concentrations in order to create a form of gavantium with a different set of properties, each as indestructible as the other. It could either be opaque and rough like the walls of a Wargames arena, soft and malleable like a heart protector, or even have transparent, glass-like properties like the screens used to protect audiences inside Wargames stadiums.