Mike knows of the stone?

"Jon, you gotta use the stone and change me." Jon was confused. How did mike know of the stone? How did mike know he was changed if he didn't hear himself being changed? "Uhm.... Mike, the stone.. well... I don't think it can do this." Jon said. Jon wondered if he should explain, how would Mike react if he knew Jon was the one who changed him? Maybe he should find out how Mike knew about the stone first. Or how Mike knew he was changed. Besides, what if Mike hurts him if he knew jon changed him.