"Hermione, we suspect that Riddle went through with his plan to split his soul into seven pieces," said Harry. "We can chalk off six of the Horcruxes he made - the ring, the diary, the locket, the diadem, the goblet, the snake - then there's whatever is left in Tom, himself. But we are working on the assumption that he actually made a seventh Horcrux after he regained his body. It was his life's work. It made sense that he'd finish it first chance he got."