A mineral boasting diamond-like hardness. Functions as a transformational catalyst.
Chapter 11 (Available after completing Mission 07)
Adamantite is an annoying component, because it cannot be found anywhere, only purchased. While there are more expensive components out there, you can find those, making Adamantite the biggest money sink in the game. Fortunately, only three weapons require it for upgrading, though the accessories that use it are pretty nice in their own right.