Well, thinking about it... the geodes make a modicum of sense. Pewter's Gym Leader trains Rock type Pokemon, and I'd be surprised if they weren't at least part rock... but they also seem to have some sort of strange resistance to Dragons, which have something of a following in Blackthorn.

...no idea about the keys, though. But for all we know, they could evolve into something like that, or they could just be more useful in a fight than they seem.