Star Wars: Splinter of the Mind's Eye #4 (1996)

Mimban is like a million other planets in the galaxy -- a lot of trees, too much mud, and not much else. But one of Mimban's abandoned temples holds a powerful gem -- the Kaiburr crystal -- capable of magnifying and clarifying one's perception of the Force. Luke and Leia know it's there -- somewhere -- and so does Darth Vader. And that makes Mimban a whole lot livelier right now than those other planets!