The Janka hardness test measures the force in pound per square inch required to embed a 0.444" steel ball to half its diameter in a 2" x 2" x 6" piece of wood. This test is a good measurement of how a wood product will withstand denting and wear. By the same token, it's also a good indicator of how hard a species is to saw or mill. The table to the right indicates testing results on different hardwood flooring species, including some acrylic impregnated species. The Janka test is also a good indicator of how hard it would be to saw or nail into a species of wood. The higher the Janka measure, the harder and more resistant it is to denting. For example, Brazilian Teak with a Janka rating of 3540, one of the hardest species available, is almost three times as hard as Red Oak, rated at just 1360.