To add a hint more specificity, it is a burl. Obviously some lighter wood. To which a red dye treatment has been applied. (The red is not part of the natural color of the wood. You can get some cool effects with dyes and burls.)
Mr Ellis's craftsmanship is just amazing, I must say.
-Mo
I'm a take a guess, and say it's elderbox. Congrats on the gorgeous blade. How's about some in-the-hand photos?