"...the walnut wand will, once subjugated, perform any task its owner desires, provided that the user is of sufficient brilliance."
-- Mr. Ollivander (Pm)
A wand wood (Pm).
- A walnut wand can become a lethal weapon in the hands of a wizard with no conscience (Pm)
- Bellatrix Lestrange had a walnut wand, 2 3/4", unyielding, with a dragon heartstring. It was taken from her by Ron Weasley at Malfoy Manor, who Disarmed her using Wormtail's wand. Since Mr. Ollivander identified it so precisely, it seems likely that he originally made the wand (DH23, DH24).
Rowling, when asked what her won wand would be, responded:
"Phoenix feather and... let's see... possibly walnut, I love walnut wood" (CR).