Top portion is finished with water-base urethane; bottom with oil-modified polyurethane.

Color: Heartwood is brown when freshly cut, turning deep purple to purplish brown over time. Sapwood is a lighter cream color.

Grain: Usually straight; medium to fine texture.
Variations within species and grades: Moderate to high color variation.

Hardness (Janka): 1860; 44% harder than Northern red oak.
Dimensional Stability: Excellent (change coefficient .00212; 43% more stable than red oak).
Durability: Very strong and dense.

Sawing/Machining: Moderately difficult due to hardness; frequent sharpening of tools required; slow feed rate and carbide tooling recommended.
Nailing: Good holding ability.
Sanding: Sands satisfactorily.
Finishing: Takes finishes well; some have found that water-based finishes hold color better. Tendency to bleed with some finishes.

Comments: Heartwood is very resistant to dry-wood termites. Presence of minerals in some boards may cause uneven coloration.

Information is from The National Wood Flooring Association
"Wood Species Used in Wood Flooring"