Aetherstone

Magic stones that carry the power of the aether, that originated outer space, or are made deep in the mountains and undercaverns of Astra's crust. An aetherstone may be primordial, galactic, nebular, astral, or even terrestrial in nature.
The material that originally reacts with the aether to form the rock can yield various effects and intensity levels of the magic contained within.
Also: Aetherium or Aether rocks