Lair of the Brute
Instructions: Order & Destruction
No access to Bastion Stair for now
Kill Gor creatures in 'The Bastion Stair' Dungeon until one drops a 'Skull of the Bray-Shaman'. Click on it for the unlock.
Once the unlock triggered, you can claim the jewel buying it from the correct merchant in Library (Order) / Lyceum (Destruction).