"It must be a magic-controlling device, but the technology is completely out of this world."

—Terra's Chronicles

The Gulug Stone is a Magic-controlling device in Final Fantasy IX that was placed in Oeilvert, and is possibly responsible for the Anti-Magic field that is in effect there. It is of Terran design, although little else is known about it.

Kuja sends Zidane to Oeilvert to retrieve the stone so that he could enter Mount Gulug. When the player first gains access to the Blue Narciss, they can go to Esto Gaza, and if they try to reach Mount Gulug the way is blocked by a door that has a seal shaped like the Gulug Stone.