- This article presently only relates to the Turner sclerometer for measuring the hardness of metals and minerals and not to the Schmidt sclerometer for determining the compressive strength of concrete. The objectives and operating principles of these two instruments are different (2019-12-31).
The sclerometer, also known as the Turner-sclerometer (from Ancient Greek: σκληρός meaning "hard"), is an instrument used by metallurgists, material scientists and mineralogists to measure the scratch hardness of materials. It was invented in year 1896 by Thomas Turner (1861–1951), the first Professor of metallurgy in Britain, at the University of Birmingham.
The Turner-Sclerometer test consists of microscopically measuring the width of a scratch made by a diamond under a fixed load, and drawn across the face of the specimen under fixed conditions.