The Crystalmists are a fictional mountain range bordering the Dry Steppes with Geoff, Sterich, and Yeomanry in the Flanaess the Greyhawk Campaign setting in the Dungeons & Dragons role-playing game. The Crystalmists were the source of the Giant invasion Against the Giants: The Liberation of Geoff in Common Year CY 583/ Flan Tracking (FT) 2463.