Wraithbone
Wraithbone is a material used by Eldar to make weapons, vehicles, and buildings. It is strong, lightweight, and most unusually, it is slightly psychic.
Rather than being cut, stamped, and welded into a particular form, wraithbone constructs are grown. The growth of wraithbone is controlled by Eldar specialists known as Bonesingers, directing it to grow into the desired shape.
Wraithbone structures are life-like in many ways; wraithbone will regrow and heal itself if damaged (a process that Bonesingers can accelerate), and they conduct and generate psychic energy. Craftworlds and other vehicles and buildings use their wraithbone skeletons to transmit this energy throughout their interiors and power onboard devices, a system known as an infinity circuit.