Which seeing-stone does Saruman use in Orthanc?

Saruman uses the Palantír of Orthanc, a seeing-stone kept in the tower of Isengard. The palantíri were powerful crystal devices made in the Blessed Realm by the Noldor and later brought to Middle-earth by Elendil and his sons. They allowed users to observe distant places and communicate with other stones.

Saruman’s stone connected him with Sauron, who possessed the palantír of Minas Ithil. Although Saruman believed he could use the stone to gather knowledge and rival Sauron, the Dark Lord manipulated what he saw and gradually dominated him. This helped turn Saruman from a cautious wizard into an ally of Mordor.

A common mix-up is the Palantír of Minas Tirith, also called the Anor-stone. That stone belonged to the Stewards of Gondor and was used by Denethor. The Palantír of Orthanc later becomes important when Gríma throws it from the tower and Pippin, followed by Aragorn, looks into it.