"[Voldemort] was plainly dressed in a black suit; his hair was a little longer than it had been at school and his cheeks were hollowed, but all of this suited him; he looked more handsome than ever.
. . . [Hepzibah] slid back the fine filigree clasp and flipped open the box. There upon the smooth crimson velvet lay a heavy golden locket.
Voldemort reached out his hand . . . and held it up to the light, staring at it.
"Slytherin's mark," he said quietly, as the light played upon an ornate, serpentine S.
. . . Voldemort's eyes flashed scarlet . . . and . . . his knuckles whiten[ed] on the locket's chain."
(Harry Potter and the Half-Blood Prince, Chapter Twenty: Lord Voldemort's Request, Pg 434, 437)
This drawing is my envisioning of a scene from "The Half-Blood Prince", where Harry Potter and Dumbledore are visiting memories involving Tom Riddle, aka Voldemort, in the past. At this point in Riddle's history, he has left Hogwarts and is working as an employee at Borgin and Burkes, and he visits an old woman by the name of Hepzibah to barter a price for items the store seeks. She then shows him (after a decent amount of flattery on her part) a goblet that belonged to Hufflepuff, and Salazar Slytherin's locket. Both items fill Riddle with immense interest and curiosity, and he is affixed to both items with an intensity during with his eyes flash crimson briefly. These two items are what ultimately become Voldemort's Horcruxes, alongside his mother's ring, the diary, and later his beloved snake, Nagini.
Riddle was easy enough to draw, based on the description in the text, the locket was of my own imagination (even though I have looked at a picture of the locket present in the film adaptation), and Hepzibah's design was taken from the illustration of her at the beginning of the chapter, by Mary GrandPre.
As with my recent drawings, the scan did not turn out right. I played around with levels on GIMP, but there was little I could do to make it resemble the original colored pencil drawing. So what you are seeing is not how it truly looks.
(c) J.K. Rowling