Discussion on Norway Maple Vs. Sugar Maple differences in the look of the trees in the Wikipedia in the link I provided.

Here is a link that might be useful: Discussion on Norway Maple Vs. Sugar Maple differences in the look of the trees in the Wikipedia

Norway Maple also grows in the USA.

Here is a link that might be useful: Norway Maple also grows in the USA

Subject: hard maple includes both Sugar Maple & Norway Maple so most likely both have a Janka Rating of 1450.

Hard Maple Color: creamy white to off white sapwood-tinged occasionally with slight red brown heartwood
Density: hard, heavy and strong, very resistant to shock and abrasive wear

Grain: closed grain, uniform texture. Some of the figured Hard Maple is available (Curly, Birdseye, and Quilted)

Machinability: excellent, will tear out with dull tooling
Finishing: Finishes very well. Some of the figured woods will show variable levels of penetration.
Distinctive Characteristics: Great wood for applications requiring hardness. Birdseye and curly patterns are available.
Common Uses: furniture, handles, cabinets, woodenware, flooring, paneling, millwork and mouldings
Other Names: Sugar Maple, Black Maple, Norway Maple, Rock Maple

Available in Certified: Check for availability

I added based on my research: NOTE RED MAPLE is a SOFT MAPLE not good for flooring but Norway Maple and Sugar Maple are both hard maples good for flooring.

http://www.lewislp.com/woodchar.asp

Here is a link that might be useful: OK after over 1 hr of research trying to help, this is all I can really find & it seems that Norway Maple is a hard maple like Sugar Maple & is an invasive tree- think wood looks similar & both are hard maples.

I am surprised that you can find Norway maple flooring in the States as it is typically an ornamental tree, an introduced species, and not native in our forests. So if it coming from a large commercial flooring source, then it is probably from Europe where it is native.

Norway Maple is in the "soft" hardwood category with a specific gravity of .54, which is the same as our red maple. Sugar maple, at .63, is a "hard" maple. Black walnut, for comparison, is .55 and southern pine is between .51 and .59. So Norway maple could definitely be used for a wood floor, but it will show dents more than the harder woods.

The general relationship with wood is that higher density means less stability (more shrink/swell) and lower density means greater stability. Thus, old-growth and tight ringed oak is less dense than faster growing second-growth oak, but it is also more stable.

You can get a more stable wood floor with any species by specifying rift and quarter-sawn material. This type of cut may cost a little more than the typical plain-sawn flooring and it also has a more uniform look.

My USA published wood tech book didn't have any info on Norway Maple, so I did an internet search. Yahoo search picked up this credible source as number 4 on the list when searching for: norway maple+ specific gravity. One error (or possible historic taxonomy change) on this link is the scientific listing of Acer platanus instead of the currently accepted Acer platanoides for Norway maple. Regardless, the wood or trade name is the same and this is the wood info. you requested.

Here is a link that might be useful: Norway Maple

I have to correct what I just posted. The UK specific gravity listing standards and the USA standards must not be the same. My USA wood tech book lists Sugar maple at .63 specific gravity (12% MC) and .56 green. The wood explorer site lists it as .55, so they must be using green for the measurements. Thus, Norway maple at .54 appears about the same as sugar maple and thus is a "hard maple."

My experience with the tree in the states is that it is more commonly broken in storms, but that could be more related to growing on poor urban sites.

Sorry for the confusion.