1 stone rubbles were created in one of two ways:

  • Replacement rubbles were created by the devs with 1 stone.
  • If two stackable rubbles are stacked, then one is removed from the stack, the two rubbles will not have the same weights they began with. One with have half the combined weight, the other will be 1 stone. So if two stackable rubbles have 50 and 90 stones weight to begin with, then 140 stones combined weight, when they are then split apart, they will have 70 and 1 stone weights. When restacked, however, the stack will again weigh 140 stones.