There was a name carved into the stone. It was JON.
"I wish I knew why my name is on it," he said, holding the stone. In a flash, he knew. This wasn't his stone. This stone only let people with the name "Jon" make wishes. Otherwise, it was the same as the normal stone, with all the same limitations.
At first, Jon thought that he should wish back the other stone, where ever it might be. But then he thought it might be safer if only he was the one that could use the stone. Well, anyone that had the name "Jon", but he didn't know too many people like that. And what was the chance of something like that happening?
Should Jon wish back the normal stone, or keep this one?