Wood Flooring Hardness
The Janka hardness is a test that measures the pound of force required to embed a .444-inch steel ball to half its depth into wood. This is the industry standard for measuring the ability of a wood species to withstand denting and normal wear. In addition it indicates the required effort it will take to saw or nail a certain wood species.
Please note that the higher the number the harder the species. Also this is a partial list of wood species.
Source: The hardness ratings for most species were taken from the U.S Department of Agriculture, Forest Service, Forest Product Laboratory, and the Center for Wood Anatomy Research.