indentation
131hardness tester — ▪ device device that indicates the hardness of a material, usually by measuring the effect on its surface of a localized penetration by a standardized rounded or pointed indenter of diamond, carbide, or hard steel. Brinell hardness is …
132Knoop hardness — ▪ mineralogy a measure of the hardness of a material, calculated by measuring the indentation produced by a diamond tip that is pressed onto the surface of a sample. The test was devised in 1939 by F. Knoop and colleagues at the National… …
