Eternity Crystal
From Wookieepedia, the Star Wars wiki.
The Eternity Crystal was alledgedly the pinnacle of Jerni science, capable of winding back time to a horrendous event, and guiding the future (present) in a different and more positive direction.
The crystal was supposedly hidden in the Jerni ruins near Adony Station, but it turned out the whole thing was a hoax devised by Darth Vader in an attempt to kill Luke Skywalker and Leia Organa.
