Oracle stone
From Wookieepedia, the Star Wars wiki.
The Sith oracle stone was an ancient Sith artifact that could be used to aid a user's clairvoyance. The powers granted by the oracle stone could be detected and countered by a Jedi using battle meditation, however.
During his pilgrimage to the planet Korriban, the reborn Emperor Palpatine used it to locate Anakin Solo so that he might be able to use the young child's body to prolong his existence.
