Item from harry-potter-deathly-hallows by
The first Horcrux -- destroyed by Harry with a Basilisk fang in the Chamber of Secrets five years ago. Referenced as proof that Horcruxes can be destroyed and that Voldemort made more than one.
The diary was destroyed in Harry's second year, though he didn't know what a Horcrux was at the time. Its destruction proved two critical things: Horcruxes could be destroyed, and Voldemort had made them. Dumbledore used the diary as the starting point for his investigation into how many soul fragments Voldemort had created. It is referenced throughout the Horcrux hunt as the precedent -- the first proof that what they're doing is possible.
A thin, black diary with T.M. Riddle embossed in gold. Pages that absorbed ink and wrote back. Destroyed -- a hole punched through its center, black ink dried like blood around the wound.
Also known as: Tom Riddle's diary, the diary