How to Identify Black Walnut Wood (Juglans nigra)

Black Walnut, Juglans nigra: color, grain, end grain, Janka hardness (1,010 lbf) and weight, and how to tell it from Yellow Poplar (Tulip Poplar), quoted from the USDA Wood Handbook and The Wood Database.

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At a glance

Scientific name: Juglans nigra
Type: Hardwood
Origin: Eastern United States
Color: Heartwood ranges from a lighter pale brown to a dark chocolate brown with darker brown streaks.
Grain and texture: Grain usually straight but can be irregular; medium texture with moderate natural luster.
End grain: Semi-ring-porous (sometimes closer to diffuse porous); vessels large to very large in earlywood grading to medium in latewood, few to very few, tyloses common; parenchyma diffuse-in-aggregates and banded; rays narrow to medium, generally not visible without magnification.
Janka hardness: 1,010 lbf
Specific gravity (12% MC): 0.55
Other clue: Faint, mild odor when being worked, which helps distinguish it from unrelated walnut lookalikes; reported as a sensitizer causing eye and skin irritation.

What Black Walnut looks like

Heartwood ranges from a lighter pale brown to a dark chocolate brown with darker brown streaks. Grain usually straight but can be irregular; medium texture with moderate natural luster. End grain: Semi-ring-porous (sometimes closer to diffuse porous); vessels large to very large in earlywood grading to medium in latewood, few to very few, tyloses common; parenchyma diffuse-in-aggregates and banded; rays narrow to medium, generally not visible without magnification.

Hardness and weight

Janka hardness 1,010 lbf (side hardness: the force needed to embed a 0.444-inch steel ball to half its diameter). Specific gravity 0.55 at 12% moisture content, so a cubic foot weighs roughly 34 lb. Weight in the hand is one of the quickest checks: compare a piece of known size against a board you already know.

Black Walnut vs Yellow Poplar (Tulip Poplar)

Yellow-poplar and other pale, inexpensive hardwoods are sometimes stained dark to mimic walnut's color; genuine walnut shows real dark-brown heartwood streaks running with the grain and a much higher density/hardness (1,010 lbf vs. poplar's 540 lbf) and medium (not fine/light) texture, whereas dyed color sits only on the surface and the underlying wood is lighter and softer. The Yellow Poplar (Tulip Poplar) page has its own details.

Smell, weight and other clues

Faint, mild odor when being worked, which helps distinguish it from unrelated walnut lookalikes; reported as a sensitizer causing eye and skin irritation.

Where you will meet it

Furniture, cabinetry, gunstocks, interior paneling, veneer, turned items, and other small wooden objects and novelties.

Working it

Typically easy to work provided the grain is straight and regular; planer tearout may occur with irregular grain; glues, stains, and finishes well (though rarely stained); reported as a sensitizer causing eye and skin irritation.

How to photograph it for identification

Photograph a freshly cut or sanded face in daylight, not a finished or stained surface, since stain hides color and finish flattens grain. Add a close-up of the end grain: cut a clean end, wet it or sand it to 220, and shoot from straight on; pore pattern and rays are the most reliable marks. Put a ruler in frame. The app suggests the likely species; confirm with the end grain and weight.

FAQ

How hard is Black Walnut?

Janka hardness 1,010 lbf. For comparison, Red Oak is about 1,290 lbf and Eastern White Pine about 380 lbf.

How do I tell Black Walnut from Yellow Poplar (Tulip Poplar)?

Is Black Walnut a hardwood or a softwood?

Black Walnut is a hardwood: it comes from a broadleaf tree. Hardwood and softwood describe the kind of tree, not how hard the wood is; some hardwoods are softer than some softwoods.

What color is Black Walnut?

Heartwood ranges from a lighter pale brown to a dark chocolate brown with darker brown streaks.

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