The Power stone is found on the corpse of a Salamandra mage after a battle at the Salamandra hideout in the restricted part of the Trade Quarter. It is used to activate Alvaro's portal, a teleporter at the Salamandra base. It is found, along with a seeing stone used to activate a telecommunicator, Hartmann's mirror, at the hideout when Geralt is investigating on behalf of Leuvaarden.
There are at least two power stones in the game.
- The first stone can be retrieved from the body of the Salamandra mage after the fight at the Salamandra hideout in the restricted area, but if you fail to find that stone, do not worry, there is another one.
- The second power stone is in the same chamber of the Salamandra base as Alvaro's Portal. Before proceeding to the portal (which is to the left), go to the right (I thought at first that this was a mistake in the game text, but it is not). There is a little alcove on the right guarded by a lone Salamandra mage. In there is a circle of elements (Yrden), a crate with some goodies, an informative little document you can read, if not pick up, and a second power stone (called "Stone of Power") in front of the circle, in one of those little three-legged stands you see here and there in the game.