Arcanum Crystal

Arcanum Crystal is a rare mineral that primarily grows only in the nation of Estor. This crystal, which literally grows be absorbing ambient magic from the air, is generally clear but will tint itself into different colors based on the exact flavors of magical energy that it had absorbed while growing. Once these crystals are broken from the earth, their properties change slightly. They become capable of absorbing much larger amounts of energy and storing the energy instead of channeling it into growth which means that they can be used as excellent arcane batteries.

This property is sometimes credited for the reason that the Old Gnomes of Estor were capable of extraordinary magical development that dwarfed the rest of the world. Arcanum crystal could be used to great effect in both artificing and in ritual magic by allowing energy to easily be stored and re-purposed with at a much greater efficiency than moving the energy through a more typical medium such a blood, water, trees, or a living subject.

The reason that arcanum crystal only grows in Estor is currently unknown. There are some legends that say that long ago a god of magic was killed in Estor, and everywhere it's blood touched the ground the crystal began to sprout. While this story is not widely supported, there are some strange pieces of evidence that support the story and no other real theories as to while the crystal grows.