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Hardnesses of the elements (data page) 10 languages. ... Mohs hardness of materials (data page) Vickers hardness test; Brinell scale This page was last edited ...
Mohs hardness kit, containing one specimen of each mineral on the ten-point hardness scale. The Mohs scale (/ m oʊ z / MOHZ) of mineral hardness is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of minerals through the ability of harder material to scratch softer material.
Two scales that measures rebound hardness are the Leeb rebound hardness test and Bennett hardness scale. Ultrasonic Contact Impedance (UCI) method determines hardness by measuring the frequency of an oscillating rod. The rod consists of a metal shaft with vibrating element and a pyramid-shaped diamond mounted on one end. [4]
Elements with small molar volumes and strong interatomic forces usually have high bulk moduli. Bulk moduli was the first major test of hardness and originally shown to be correlated with the molar volume (V m) and cohesive energy (E c) as B ~ E c /V m.
The Brinell hardness is designated by the most commonly used test standards (ASTM E10-14 [2] and ISO 6506–1:2005) as HBW (H from hardness, B from brinell and W from the material of the indenter, tungsten (wolfram) carbide). In former standards HB or HBS were used to refer to measurements made with steel indenters.
Due to great hardness and strong molecular bonding, a cut diamond's facets and facet edges appear the flattest and sharpest. A curious side effect of a natural diamond's surface perfection is hydrophobia combined with lipophilia. The former property means a drop of water placed on a diamond forms a coherent droplet, whereas in most other ...
The hardness of osmium is moderately high at 4 GPa. [17] [18] [19] Because of its hardness, brittleness, low vapor pressure (the lowest of the platinum-group metals), and very high melting point (the fourth highest of all elements, after carbon, tungsten, and rhenium), solid osmium is difficult to machine, form, or work.
In its pure form, molybdenum is a silvery-grey metal with a Mohs hardness of 5.5 and a standard atomic weight of 95.95 g/mol. [18] [19] It has a melting point of 2,623 °C (4,753 °F), sixth highest of the naturally occurring elements; only tantalum, osmium, rhenium, tungsten, and carbon have higher melting points. [12]