Also, Dumbledore is obviously capable of recognizing horocruxes. Else he wouldn't have been SURE that the ring was one. He's had Harry under his nose for years now. Surely if Harry were a horocrux Dumbledore would have known about it by now and would not have talked about the powerful magic of the love of his mother that saved him.
Love does not seem to be an ingredient in horocrux cookery
