The Identity Stone

The stone he put in its place looked exactly like Jon's stone, except that it had someone's name carved into it. It was the Identity Stone. It worked just like the normal stone, except that only a person with the name that was carved into the stone could use the stone and have their wishes granted. And anyone who didn't have that name that tried to make a wish with the stone would *not* have their wishes granted. But whose name was on the stone?