There is some confusion over the term 'Master Stone', because there are references to another palantír variously known as the 'Masterstone' or 'Master-stone', held in the Tower of Avallónë on Tol Eressëa. The implication of this is uncertain, but it appears that the Master Stone of Osgiliath had power only over the other six palantíri of Middle-earth, and not those that still existed in the West.