1) Concrete 2) Measuring device 3) Measuring instrument 4) Measuring system 
The sclerometer, also known as the Turner-sclerometer (from σκληρός meaning `hard`), is an instrument used by metallurgists, material scientists and mineralogists to measure the scratch hardness of materials. It was invented in 1896 by Thomas Turner (1861–1951), the first Professor of metallurgy in Britain, at the University of Birmingh.....
instrument measuring hardness
• (n.) An instrument for determining with accuracy the degree of hardness of a mineral.
A device for determining the density or hardness of any substance. ... Origin: sclero-+ G. Metron, measure ... (05 Mar 2000) ... 
Instrument used to determine the absolute hardness of a mineral. A mineral is locked into position , and a Diamond pin pushes down and slightly scratched the mineral. The amount of pressure needed for the Diamond pin to be pushed down to scratch the mineral determines its hardness.
Scle·rom'e·ter noun [ Greek 
Type: Term Pronunciation: sklē-rom′ĕ-tĕr Definitions: 1. A device for determining the density or hardness of any substance.
[n] - a measuring instrument that measures the hardness of materials by penetrating them with a stylus that has a diamond point
noun a measuring instrument that measures the hardness of materials by penetrating them with a stylus that has a diamond point