Stone of Barenziah: Mistveil Keep
One of the 24 Unusual Gems. Vex in the Ragged Flagon names them once you are in the Thieves Guild.
- Stones of Barenziah – The Rift
Where to get it
On the bedside table left of the bed in the Jarl's chambers: upstairs and through the locked middle door.
Found in Riften.