Hardness testing is a test to determine the resistance a material exhibits to permanent deformation by penetration of another harder material. It is a characteristic of a material, not a fundamental physical property. It is used to evaluate a material's properties, such as strength, ductility and wear resistance, and to check if a material meets a specification, standard or code. Hardness testing uses indenters shaped as pyramids and balls to press, hit or scratch objects and measure the size of the indentation.