I'm 100% sure it's walnut. Aged walnut will often get a reddish tint to it. It also loses it dark brown/black color as it ages, giving it a light brown color, often with a red tint.
You have a perfect example of a stressed, slow-growth walnut. I'm guessing it has some pretty tight growth rings?
You have a perfect example of a stressed, slow-growth walnut. I'm guessing it has some pretty tight growth rings?