Find a room with tiles located on the floor. Run over all of the pressure plates until they are all lit up. This will open the gate. The ring is on a pedestal inside the room where the gate opened up.
"Allows you to cast the spells Ignite and Freeze."
- Followers wearing the ring can possibly be able to use the spells ignite and freeze, even though they are not naturally spellcasters.
- This might be a reference to Morrowind's enchanting system, in which you could have used ring to cast spells.