The Palantiri Summary

While the use of the Palantiri was never a common occurrence, they were not sinister objects until after the fall of the king. In time, the stones are destroyed one by one until only the Anor-stone in Minas Trith and the Orthanc-stone remained at all. In fact, by the time Beren gave the Orthanc to Saruman, the stone it contained was all but forgotten. Even when Saruman cut all ties with Gondor and claimed Isenguard as his own, the stone is still not in the forefront of anyone's mind. It is not until Pereguin looks into the stone that the link between the remaining stones and Sauron is discovered. It is thought that Gandalf knew of the existence of the Anor-stone, but its existence had become a complete secret at that point.

Much of what was once known about the stones...