Scratch hardness Scratch hardness Scratch hardness tests are used to determine the hardness of a material to scratches and abrasion. The earliest test was developed by mineralogist Friedrich Mohs in 1820 (see Mohs scale). It is based on relative scratch hardness, with talc assigned a value of 1 and diamond assigned a value of 10. Mohs' scale had two limitations; it was not linear, and most modern abrasives fall between 9 and 10. Raymond R. Ridgway, a research engineer at the Norton Company, modified the Mohs scale by giving garnet a hardness of 10 and diamond a hardness of 15. Charles E.
Measuring cup be read from an external scale; metal ones only from a dipstick or scale marked on the inside. Measuring cups usually have capacities from 250 mL (approx. 1 cup) to 1000 mL (approx. 4 cups = 2 pints = 1 quart), though larger sizes are also available for commercial use. They usually have scale markings at different heights: the substance being measured is added to the cup until it reaches the wanted level. Dry measure cups without a scale are sometimes used, in sets typically of 1/4, 1/3, 1/2, and 1 cup. The units may be milliliters or fractions of