American Black Walnut
Color: Heartwood ranges from a deep, rich dark brown to a purplish black. Sapwood is nearly white to tan. Difference between heartwood and sapwood color is great; some flooring manufacturers steam lumber to bleed the darker heartwood color into the sapwood.
Grain: Mostly straight and open, but some boards have burled or curly grain. Arrangements of pores is similar to hickories and persimmon, but pores are smaller in size.
Variations Within Species And Grades: Great variety of color and figure within species, as well as variation in color among boards, especially in lower grades and from material that isn’t steamed prior to kiln-drying.
Hardness/Janka: Janka: 1010; (22% softer than Northern red oak).
Dimensional Stability: Average (7.8; 9% more stable than Northern red oak).
Durability: Moderately dense, very strong, good shock resistance. Not as dent-resistant as oak.