When a girl is for the most part unattractive, but has one body part that not only is redeeming, but breathtakingly amazing. For instance, a girl looks amazing from behind with a perfect ass, but turns around, revealing a hideous
face or flat chest. Similar to
butterface, but not limited to body vs.
face. The name refers to the arousing part not belonging, just like a precious jewel that has been placed on the wrong body.
Also not to be confused with fat chick tits.