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Carl Friedrich Christian Mohs (/ m oʊ z / MOHZ, German: [ˈfʁiːdʁɪç ˈmoːs]; 29 January 1773 – 29 September 1839) was a German chemist and mineralogist. He was the creator of the Mohs scale of mineral hardness. [1] Mohs also introduced a classification of the crystal forms in crystal systems independently of Christian Samuel Weiss. [2]
For example, some sources have assigned a Mohs hardness of 6 or 7 to granite but it is a rock made of several minerals, each with its own Mohs hardness (e.g. topaz-rich granite contains: topaz — Mohs 8, quartz — Mohs 7, orthoclase — Mohs 6, plagioclase — Mohs 6–6.5, mica — Mohs 2–4).
Johann Friedrich August Breithaupt (16 May 1791 – 22 September 1873): Mohs, Friedrich (1825). Treatise on mineralogy, or, The natural history of the mineral kingdom by Frederick Mohs. Translated by Johann Friedrich August Breithaupt. Edinburgh: Hurst, Robinson. Note: translated from the German, with considerable additions.
[3] [4] The Mohs scale is based on relative scratch hardness of different materials; with talc assigned a value of 1 and diamond assigned a value of 10. [5] 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 ...
The Mohs scale of mineral hardness, based on scratch hardness comparison, defines value 1 as the hardness of talc, the softest mineral. When scraped on a streak plate , talc produces a white streak, though this indicator is of little importance, because most silicate minerals produce a white streak.
1822 - Friedrich Mohs attempted to bring the molecular approach of Haüy and the geometric approach of Weiss into agreement. [18] 1823 - Franz Ernst Neumann invented a system of crystal face notation, by using the reciprocals of the intercepts with crystal axes, which becomes the standard for the next 60 years. [19]
In his “Treatise on mineralogy” of 1825, also called “The natural history of the mineral kingdom”, Friedrich Mohs gave only two mineralogical synonyms for axotomous antimony glance: Prismatoidal Antimony-Glance or Grey Antimony (with the note: “in part”), [3]: 26 since the latter name, including also the longer version gray antimony ore, often also meant other ores, primarily stibnite.
Mineralogy applies principles of chemistry, geology, physics and materials science to the study of minerals. Mineralogy [n 1] is a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical (including optical) properties of minerals and mineralized artifacts.