Walnut hardwood has beautiful, distinct differences in color between the nearly white sapwood and the heartwood, which ranges from a deep, rich, almost chocolate brown to a purplish black. The species often has a purplish cast with dark streaks. The grain of Walnut is mostly straight and open, although some boards may have a grain pattern that is burled or curly. The wood surface is generally fairly dull, though it may develop a lustrous patina after many years in use
Known in Europe simply as “Walnut,” or “Common Walnut,” English Walnut (Juglans regia) is the source of what are the most common form of edible walnuts for human consumption. Branches of English Walnut are sometimes grafted onto the trunk of Claro Walnut trees in Californian walnut orchards to take advantage of the latter tree’s roots, which are better suited to the locale and produce more fruit.