Storm's End - Pathfinder
The Orb of Mul’Dune.
This semi transparent orb appears to be made of glass, but does not appear to have so much as chipped despite being hit with a scimitar and knocked onto the stone floor of the Necromancer’s lair.
Elmon Mul’Dune was a powerful spell-caster who lived thousands of years ago. He is said to have single handedly defeated the archdevil Dispater’s army.