Color/Appearance: Heartwood can range from a lighter pale brown to a dark chocolate brown with darker brown streaks. Color can sometimes have a grey, purple, or reddish cast. Sapwood is pale yellow-gray to nearly white. Figured grain patterns such as curl, crotch, and burl are also seen.
Grain/Texture: Grain is usually straight, but can be irregular. Has a medium texture and moderate natural luster.
Endgrain: Semi-ring-porous; large earlywood pores grading to medium latewood pores, few; solitary and radial multiples of 2-3; tyloses occasionally to abundantly present; growth rings distinct; rays barely visible without lens; parenchyma banded (marginal), apotracheal parenchyma diffuse-in-aggregates (sometimes very faint and barely visible even with lens).
Rot Resistance: Black Walnut is rated as very durable in terms of decay resistance, though it is susceptible to insect attack.
Workability: Typically easy to work provided the grain is straight and regular. Planer tearout can sometimes be a problem when surfacing pieces with irregular or figured grain. Glues, stains, and finishes well, (though walnut is rarely stained). Responds well to steam bending.
Odor: Black Walnut has a faint, mild odor when being worked.
Comments: It would be hard to overstate Black Walnut’s popularity among woodworkers in the United States. Its cooperative working characteristics, coupled with its rich brown coloration puts the wood in a class by itself among temperate-zone hardwoods. To cap it off, the wood also has good dimensional stability, shock resistance, and strength properties.
Information´s link: http://www.wood-database.com/black-walnut/