Magnesium is a mineral found in a wide variety of foods. Inside of our bodies we mostly find magnesium in our bones (60-65%), in our muscles (25%) and in other cell types and body fluids. Magnesium cannot be made in our body like all minerals, which is why we need to take it in through magnesium-rich foods.
The Brinell hardness number (HB) is the load divided by the surface area of the indentation. The diameter of the impression is measured with a microscope with a superimposed scale. The Brinell Hardness Number is computed from the equation: P is the applied load of 3000, 1500, or 500kg.
The Rockwell hardness tester to measure the hardness of metal measures resistance to penetration like the Brinell test, but in the Rockwell case, the depth of the impression is measured rather than the diametric area. With the Rockwell tester, the hardness is indicated directly on the scale attached to the machine.