The Citadel of White Exile was a place located on the border between the Positive Energy Plane and the Plane of Gems.
The Citadel itself was a tall white tower, with the top not more than fifty feet (15.2 m) from the Positive Energy Plane. The tower stood on grey stone. The sky had healing properties.
There were only two entrances, one leading to the Hill of Fangs near Westgate, and one to the Abyss and (eventually) to the home plane of the god Moander.
It served as the prison of Finder, since time did not pass normally there.