Q. Which wood board is hardest?

The Janka hardness test is used to determine how tough different types of wood are. In this particular test the amount of force necessary to drive a steel ball with a diameter of 0.444 inches into a piece of wood to a depth equal to half the ball's diameter is measured. On the janka hardness scale lignum vitae has a 4500-pound-force (lbf) reading which indicates that it is the world's hardest wood.