Mohs hardness kit, containing one specimen of each mineral on the ten-point hardness scale
The Mohs scale of mineral hardness (/moʊz/) is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of minerals through the ability of harder material to scratch softer material.
The scale was introduced in 1812 by the German geologist and mineralogist Friedrich Mohs, in his book "Versuch einer Elementar-Methode zur naturhistorischen Bestimmung und Erkennung der Fossilien";[1][2] it is one of several definitions of hardness in materials science, some of which are more quantitative.[3]
The method of comparing hardness by observing which minerals can scratch others is of great antiquity, having been mentioned by Theophrastus in his treatise On Stones, c. 300 BC, followed by Pliny the Elder in his Naturalis Historia, c. AD 77.[4][5][6] The Mohs scale is useful for identification of minerals in the field, but is not an accurate predictor of how well materials endure in an industrial setting.[7]
^von Groth, Paul Heinrich (1926). Entwicklungsgeschichte der Mineralogischen Wissenschaften [History of the development of the mineralogical sciences] (in German). Berlin: Springer. p. 250. ISBN 9783662409107. In demselben Jahre (1812) wurde MOHS als Professor am Joanneum angestellt und veröffentliche den ersten Teil seines Werkes "Versuch einer Elementarmethode zur naturhistorischen Bestimmung und Erkennung der Fossilien", in welcher die bekannte Härteskala aufgestellt wurde. [In the same year (1812) MOHS was employed as a professor at the Joanneum and published the first part of his work "Attempt at an elementary method for the natural-historical determination and recognition of fossils", in which the well-known hardness scale was set up.]
^"Mohs hardness" in Encyclopædia Britannica Online
^"Mohs scale of hardness". Mineralogical Society of America. Retrieved 10 February 2021.
^Theophrastus. Theophrastus on Stones. Retrieved 2011-12-10 – via Farlang.com.
^Pliny the Elder. "Book 37, Chap. 15". Naturalis Historia. Adamas: Six varieties of it. Two remedies.
^Pliny the Elder. "Book 37, Chap. 76". Naturalis Historia. The methods of testing precious stones.
^"Hardness". Materials Mechanical Hardness. Non-Destructive Testing Resource Center. Archived from the original on 2014-02-14.
precision, the Mohsscale is relevant for field geologists, who use the scale to roughly identify minerals using scratch kits. The Mohsscale hardness of...
Christian Mohs (German: [moːs]; 29 January 1773 – 29 September 1839) was a German chemist and mineralogist. He was the creator of the Mohsscale of mineral...
Mohs or MoHS can refer to: Friedrich Mohs, a 19th-century German geologist who developed: Mohsscale, a scale used in materials science to describe hardness...
Because of corundum's hardness (pure corundum is defined to have 9.0 on the Mohsscale), it can scratch almost all other minerals. It is commonly used as an...
chemical formula is Be(Mg, Fe, Zn)2Al6O12. Its hardness is 8 to 8.5 on the Mohsscale. Due to its rarity, the mineral can sell for roughly USD$35,000 per carat...
rainbow colors, similar to opal, with a measurement of hardness on the Mohsscale of between 5 and 7 which reduces the occurrence of scratching when polished...
crystals are flexible and slightly sectile with a hardness of 2-2.5 on the Mohsscale. Fuchsite fluoresces lime green under long wave UV light. Fuchsite's radioactivity...
materials by scratch tests was by mineralogist Friedrich Mohs in 1812 (see Mohsscale). The Mohsscale is based on relative scratch hardness of different materials;...
particularly as a component of limestone. Calcite defines hardness 3 on the Mohsscale of mineral hardness, based on scratch hardness comparison. Large calcite...
spar is a silky brown variety of corundum. It has a hardness of 9 on the Mohsscale. Yogo sapphire "Adamantine Spar". Archived from the original on 18 October...
green or bronze-yellow tint. It has a hardness between 1 and 2 on the Mohsscale (between talc and gypsum). Its crystal structure is orthorhombic. Vulcanite...
gravity. Grandidierites also have greater hardness, with a 7.5 on the Mohsscale. Large transparent faceted grandidierite specimens are extremely rare...
although octahedral and more complex isometric forms are not uncommon. The Mohsscale of mineral hardness, based on scratch hardness comparison, defines value...
flat fracture, and it is foliated with a two-dimensional platy form. The Mohsscale of mineral hardness, based on scratch hardness comparison, defines value...
as an evaporite mineral and as a hydration product of anhydrite. The Mohsscale of mineral hardness defines gypsum as hardness value 2 based on scratch...
Hardness scales may refer to: Scratch hardness The Mohsscale of mineral hardness The Vickers hardness test The Brinell scale The Janka hardness test The...
steel are definitively false in terms of Mohsscale of mineral hardness. Steel can vary from 4 to 8 on the Mohsscale, depending on the type of alloy, heat...
gray to black, with a metallic luster. It has a hardness of 2.5–3 on the Mohsscale. It is a sulfide with a monoclinic crystal system. The term chalcocite...
Europe and Asia. Quartz is the mineral defining the value of 7 on the Mohsscale of hardness, a qualitative scratch method for determining the hardness...
crystal boules. Because of the remarkable hardness of sapphires – 9 on the Mohsscale (the third hardest mineral, after diamond at 10 and moissanite at 9.5) –...
harder serpentines can also reach 4 on the Mohsscale. Marble, travertine, and onyx are at about 6 on the Mohsscale. Marble has been the preferred stone for...
times that of diamond. Cubic zirconia is relatively hard, 8–8.5 on the Mohsscale—slightly harder than most semi-precious natural gems. Its refractive index...
gray in color, has chatoyancy, and has hardness between 2 and 4 on the Mohsscale of mineral hardness. Seraphinite is mined in a limited area of eastern...
masses exhibiting good cleavage. It is soft (not higher than 2.5 on the Mohsscale) and water-soluble. Optical properties are variable; the purest form is...
42 and 3.93, respectively. The hardness of cinnabar is 2.0–2.5 on the Mohsscale, and its specific gravity 8.1. Structurally, cinnabar belongs to the trigonal...
has a brassy to golden yellow color and a hardness of 3.5 to 4 on the Mohsscale. Its streak is diagnostic as green-tinged black. On exposure to air, chalcopyrite...
greatly differ. Orthoclase is one of the ten defining minerals of the Mohsscale of mineral hardness, on which it is listed as having a hardness of 6....
third-hardest frequently encountered natural gemstone and lies at 8.5 on the Mohsscale of mineral hardness, between corundum (9) and topaz (8). An interesting...
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