Vickers hardness is one of the existing techniques to measure the hardness of a material. It works thanks to an object, called indenter, which is affixed with a very precise force on a material whose print is then measured.
The larger the indentation the softer the material or the smaller the indentation the harder the material. The indenter is a diamond cut into a pyramid with a penetration angle of 136 degrees. Like all hardness tests this test is destructive.