Sierravision's The Dark Crystal (Hi-Res Adventure #6), just sold on eBay for the remarkable price of $158.63, plus shipping and handling. As you can tell, Roberta Williams' 1983 release, based on the cult classic Jim Henson movie, is among the most sought after of the original Sierra text and graphics adventures. The game received middling reviews when first released and the graphics are fairly average. The Atari 8-bit version looks almost exactly the same, just with different coloring; I am unfamiliar with the Japanese PC-xx versions. Other translations of the game were planned, but probably due to the lack of relative financial success for both the movie and game, those plans were canceled. However, Al Lowe's mostly forgotten Gelfling Adventure was released a year later in 1984 and is essentially the same game, just with a modified interface and child friendly difficulty level.
Here's some gameplay footage of the Apple II version from YouTube, via Yzzyxz: