The stone he put in its place looked exactly like Jon's stone, except that it wasn't. It was the Charity Stone, which granted wishes normally like Jon's original stone... but it also did much more than that.
Any target of a wish made by the bearer of this magic rock "“ other than the bearer him or herself - will also be given a free wish. The next time they utter the words "I wish...", their wish that will be granted, whether or not they're holding the stone at the time.
What's more, these bonus wishes follow the very same laws as if made while holding the Charity Stone itself.
