Stones of Seeing

The two Stones that survived into the Fourth Age in Middle-earth were the Orthanc-stone and the Anor-stone. The Elendil Stone of the Tower Hills was also intact at the end of the Third Age, but it was carried away from Middle-earth on the White Ship. The fate of the Ithil-stone is not absolutely certain: it was in Barad-dûr when the Dark Tower fell, and so was probably destroyed, but the palantíri were made from an incredibly resilient material, and so it might just possibly have survived.