Item from Harry Potter by J.K. Rowling
A small black diary containing a fragment of sixteen-year-old Tom Riddle's soul — the first Horcrux Voldemort created — which possesses anyone who writes in it and was destroyed by Harry with a Basilisk fang.
Riddle's diary is the most insidious of the Horcruxes because it was designed to be found. Voldemort created it as a teenager after his first murder — his own father — and embedded within it not just a piece of his soul but a working copy of his sixteen-year-old personality. The diary was meant to be opened by a Hogwarts student, possess them, and use them to reopen the Chamber of Secrets. Lucius Malfoy slipped it into Ginny Weasley's cauldron at Flourish and Blotts, and the diary-shade of Tom Riddle drained Ginny's life force while feeding her his memories and ideology. Harry destroyed it by driving a Basilisk fang through its pages, not knowing he had destroyed a Horcrux or that it would be the first of seven. The diary was also the first proof that Voldemort had made Horcruxes at all — the clue that started Dumbledore down the path to understanding how to kill him.
A thin, black, shabby-looking diary with a faded date of fifty years ago on the cover — T.M. Riddle embossed in faded gold on the back. The pages are blank until someone writes in it, at which point the diary writes back in neat, slanting handwriting. Ink sinks into the pages and vanishes. When destroyed, black ink poured from the puncture wound like blood.
Also known as: Tom Riddle's diary, Riddle's diary, the diary