Nova is an extremely tough metal. It's ore is bright green, and looks a lot like Oxmorphian ore, exept without it's radioactive qualities. When refined, this metal turns a bright chromed silver color. The ore runs in veins, but the surrounding dirt and rock around the Nova veins will also contain small amounts of the metal, so it is also collected and refined.
The metal is used to suppliment steel and titanium in armor plating, and is mixed in. Galactic Defender main battle tanks have small amounts of nova mixed in with the titanium plating, causing it to be much tougher. Many other vehichles, GD and Axari alike, have Nova mixed in.
See Nova Droid