Search results
Results from the WOW.Com Content Network
The Mohs scale is an ordinal scale. For example, corundum (9) is twice as hard as topaz (8), but diamond (10) is four times as hard as corundum. [ citation needed ] The table below shows the comparison with the absolute hardness measured by a sclerometer , with images of the reference minerals in the rightmost column.
[8] [9] Because of corundum's hardness (pure corundum is defined to have 9.0 on the Mohs scale), it can scratch almost all other minerals. It is commonly used as an abrasive on sandpaper and on large tools used in machining metals, plastics, and wood.
Tooth enamel ranks 5 on Mohs hardness scale (between steel and titanium) and has a Young's modulus of 83 GPa. [4] Dentin, less mineralized and less brittle, 3–4 in hardness, compensates for enamel and is necessary as a support. [7]
Mohs scale of mineral hardness; Mohs hardness of materials (data page) Vickers hardness test; Brinell scale This page was last edited on ...
To remember the order of taxa in biology (Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species, [Variety]): " D ear K ing P hilip C ame O ver F or G ood S oup" is often cited as a non-vulgar method for teaching students to memorize the taxonomic classification of system.
Mohs's scale had two limitations: it was not linear, and most modern abrasives fall between 9 and 10.; [6] [7] so, later scientists attempted to increase resolution at the harder end of the scale. 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.
Seraphinite is generally dark green to gray in color, has chatoyancy, and has hardness between 2 and 4 on the Mohs scale of mineral hardness. Seraphinite is mined in a limited area of eastern Siberia in Russia. Russian mineralogist Nikolay Koksharov (1818-1892 or 1893) is often credited with its discovery.
[7] [8] Phosphorite is a phosphate-rich sedimentary rock containing as much as 80% apatite, [9] which is present as cryptocrystalline masses referred to as collophane. [10] Economic quantities of apatite are also sometimes found in nepheline syenite or in carbonatites. [7] Apatite is the defining mineral for 5 on the Mohs scale. [11]