Those two guys put the marble in a special container made of iron because whenever they touched something flammable, it would emit heat and burn. Thanks to that, Billy wondered if they could be used as weapons. It would be quite something if they exploded upon contact, or at least made massive waves of flames to spread around when they were thrown with enough power. Apparently, neither of those as possible, but Billy was quite sure that he could fiddle with it and then use it in other ways. In any case, the number of materials and the diversity that one could find across the dungeons of that world was pretty high, and Billy never heard of two identical dungeons...