An item found in Number Four's Loric Chest and is one of the fabled Phoenix Stones.
When touched, they make a sound of wind which is presumed to be from Lorien. It was suggested that is serves as a reminder of what was stolen from the Garde and why they need to fight.
Beside this, any other function of this item are unknown. The item was deposited into the Sanctuary in order to awaken The Entity.