Mohs scale of mineral hardness integrity, they are not considered "scratches" for the determination of a Mohs scale number. The Mohs scale is a purely ordinal scale. For example, corundum (9) is twice as hard as topaz (8), but diamond (10) is four times as hard as corundum. The table below shows the comparison with the absolute hardness measured by a sclerometer, with pictorial examples. On the Mohs scale, a streak plate (unglazed porcelain) has a hardness of approximately 7.0. Using these ordinary materials of known hardness can be a simple way to approximate the position of a mineral on the scale. The table below
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