The Crystal of The Floorsland is the main crystal of The Floorsland. It controls everything except for the weather and the history. If this crystal goes in the wrong hands, The Floorsland could be completely ruined.
Montgomery stole this crystal in The Floorsland 3. He didn't know what to do with it, so he left it outside and went underground asking other people. He did eventually learn what to do, but Tim had already recovered the crystal. Montgomery then realized that stealing the crystals will not help, so he went to Mount Lake in order to destroy the core of The Floorsland, however he fell from 9 kilometers and died.