Blackstone

Blackstone is Aetherically inert, as it has no internal magical energy at any time. Unlike every other known material, it does not condense any amount of Aether naturally.

This strange property, however, belies that fact that it can actually hold an incredible amount of magical energy within it's being before it becomes unstable, and it holds onto all that energy like a sponge, never releasing it unless drawn out.

This makes it an idea material for magical storage, and a regular addition to the equipment of court and army mages. It's properties also make it an ideal material for the process of enchanting, especially when the Blackstone is inlaid with Crystals.