Powerstone

Powerstones are enigmatic gems once utilized to power countless Thran devices on Dominaria.

History
Urza and Mishra coveted the ancient powerstones a great deal, using many powerstone-fueled devices in the Brothers' War. The legendary Mightstone and Weakstone were halves of an extremely powerful powerstone. In ancient times, powerstones were produced in the Thran Mana Rig. The Thran artificer Glacian was the first to discover that the magical energy inside a stone could actually be restored or enhanced by absorbing space itself from a surrounding plane. Techniques to do so were used to devastating effect during the Thran-Phyrexian War. Given that powerstones contain vast amounts of energy, it is theorized that they all contain a great deal of space locked within, possibly even an entire collapsed plane.

Powerstones are not without risk however. When his exile from Thran Empire was revoked, Yawgmoth discovered that prolonged exposure to the stones can result in a sort of radiation poisoning, the effects being greatly similar to tuberculosis in our world. Also damaging a powerstone can cause all its stored energy to dissipate at once, resulting in an explosion.

Powerstones have been used in various degrees throughout history, appearing on the continents of Terisiare, Shiv, and even Jamuraa. After the Phyrexian Invasion, the construction of powerstones has ceased and various factions now covet them in order to power minor artifacts.