The Dark Crystal is a 1982 Jim Henson fantasy movie.

I haven't seen it, so here's a plagiarised synopsis from Amazon.

"A fantastical, puppet-filled adventure, this tale co-directed by Muppet creator Jim Henson and Frank Oz reveals the story of Jen, a young Gelfling boy chosen by prophecy to mend the Dark Crystal, which broke 1,000 years ago and plunged the land under the dominion of the evil, quarrelsome Skeksis. Fearing the prophecy, whose fulfillment would mean the end of their reign, the Skeksis exterminated the Gelflings--all but Jen and Kira, a girl he meets on his journey to the crystal. Pursued by the Skeksis and their dark creatures, Jen and Kira race to the crystal, even as their time runs out."