Natural walnut is varnished, but not stained. The natural color of walnut comes through.
Black Walnut is usually straight grained with a moderately coarse, uniform texture. It has rich dark brown heartwood, and nearly white sapwood. The overall color is a dark brown color with hints of grey, black, and even blue swirled out of the luxurious grain. Genuine black walnut is very rare these days -- what you think of as walnut is likely a stained variety of oak. True black walnut is a very complicated, very beautiful hardwood. With age, walnut will take on a bit of golden brown color. This change is minor. Its species name is Juglans Nigra. Its Janka rating (hardness and resistance to scrapes, gouges and cuts) is 1010.