Splinter of the Mind's Eye1978

On a mission in the Circarpous system, Princess Leia Organa and Alliance Pilot Luke Skywalker are forced to crash land on Circarpous V, a mysterious, mist shrouded world known to its inhabitants as Mimban. They quickly discover a hidden, and highly dangerous, Imperial mining operation. They encounter a much greater mystery when a chance encounter has them joining a quest for the Kiaburr Crystal, a Force amplifier so powerful it could make any Force-user nigh invincible. Luke and Leia must race against time to obtain the crystal before it falls into the hands of the Empire...