According to the Janka Hardness Scale Acacia rates at 1750 lbs in a sq inch.
The hardness rating of black walnut wood is approximately 1,010 pounds-force on the Janka hardness scale.
http://surfpick.com/hardness/ This has all the answers
The Janka Hardness Scale rates the hardness of hardwood flooring and bamboo as well. You can read more about the Janka Scale and see a list of the Janka Hardness Ratings from FindAnyFloor here http://www.findanyfloor.com/hardwood/JankaHardnessRatings.xhtml
European Oak in many ways in similar on the Janka scale as Ameriacan Oak at 1360.
The Janka hardness scale measures the resistance of a wood species to wear and denting. However, the blackthorn (Prunus spinosa) is not commonly listed on the Janka hardness scale due to its limited use in commercial applications. In general, blackthorn is known to be a very hard and dense wood, similar to other fruitwoods like cherry and plum, which typically have Janka hardness values ranging from 950 to 1200 pounds-force.
Poplar has a rating of 540.
it would depend on the species of maple. hard maple? red maple? etc. hard maple = 1450, red maple = 950
The Mohs hardness scale rating for brass is around 3 to 4.
Rubber tree wood is relatively soft and falls on the lower end of the Janka Wood Hardness Scale. Its hardness varies depending on the specific species of rubber tree, but it is typically in the range of 600-900 lbf (pounds-force).
Wood flooring is not required to meet specific hardness standards because each wood species has unique features and hardness. Hardness is measured on the Janka Hardness Scale. The Janka hardness test measures the amount of force required to push a steel ball with a diameter of 11.28 millimeters (0.444 inches) into the wood to a depth of half the ball's diameter. The result is expressed in pounds-force (lbf). If you're installing a floor in a high traffic area or you have large pets, you'll want to look at a floor with a higher Janka hardness rating because a higher hardness rating means that the floor will be more resistant to scratches, dents, and other types of damage. However, hardness isn't the only factor that goes into the durability of a floor. Other factors are the type of finish used, the amount of gloss, the number of coats, and even the grain of the wood. It's important to understand that while hardwood floors are tough, when it comes to indentations NO FLOOR is impervious to damage. The standard in the wood flooring industry is measured by comparing a given species hardness to white oak, which has a Janka rating or 1360. By comparing to domestic white or red oak you can tell how hard or soft a floor is. For species like Santos Mahogany (Janka rating 2200) or Brazilian Walnut aka Ipe (Janka rating 3680) which feature far denser grain patterns, and are thus harder and more resistant to some damage than species like North American Cherry (Janka rating 950) or Black Walnut (Janka rating 1010).
White Oak is 1360 Northern Red Oak is 1290
Janka wood hardness scale - The Janka rating is a measure of the amount of force it takes to push a .444" diameter steel ball half way into a piece of wood. The speed of growth of a tree can effect the Janka rating.