Mohs 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.

[VonGroth1926-1] 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.]

[Brit-2] "Mohs hardness" in Encyclopædia Britannica Online

[MinSocAm-3] "Mohs scale of hardness". Mineralogical Society of America. Retrieved 10 February 2021.

[4] Theophrastus. Theophrastus on Stones. Retrieved 2011-12-10 – via Farlang.com.

[5] Pliny the Elder. "Book 37, Chap. 15". Naturalis Historia. Adamas: Six varieties of it. Two remedies.

[6] Pliny the Elder. "Book 37, Chap. 76". Naturalis Historia. The methods of testing precious stones.

[7] "Hardness". Materials Mechanical Hardness. Non-Destructive Testing Resource Center. Archived from the original on 2014-02-14.

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