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

Color: Light brown to dark reddish brown.
Grain: High in character, with ingrown bark and mineral streaks. Most commonly used in flooring as end-grain block, which has small irregular cracks radiating across the grain.
Variations within species and grades: One grade; moderate color variations.

Hardness (Janka): 2345; 82% harder than Northern red oak.
Dimensional Stability: Excellent (change coefficient .00129; 65% more stable than red oak).
Durability: Dense and very strong. End-grain cut has excellent resistance to abrasion and shock.

Sawing/Machining: Very good machining qualities.
Sanding: Plainsawn can be sanded to a smooth surface; end-grain requires #16 grit sandpaper to flatten.
Nailing: Good holding ability, but splits easily.
Finishing: No known problems.
Comments: End-grain block usage results in a hard, high-wear surface. Produces only small size boards.

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