Pillar of Bone

When a storm of magic ravages the land, Arcane Fulcrums rise to meet it, great supernatural pillars from the top of which a mage can attempt to harness the magical energies raging all around. Usually, when the storm abates, the fulcrums crumble away, sinking back into the earth. Sometimes, however, the land is so wracked with sorcery that the Arcane Fulcrum remains long after the storm has passed. The Pillar of Bone is one such structure, a smooth-sided tower seemingly made from solid bone. Although the magic that once howled around its pinnacle has now subsided, a mage who sits atop the tower can still harness a glimmer of that power, scrying the future or plucking lost knowledge from the past.

Source
Blood in the Badlands (supplement)

pg. 11