Mohs
NAME:
Mohs, Friedrich
ACHIEVEMENTS:
Developed 'Mohs scale' of hardness for minerals
NICKNAME/ALIAS:
None
DATE AND PLACE OF BIRTH:
29 January 1773, Gernrode, Anhalt-Bernburg, Germany
DATE AND PLACE OF DEATH AND AGE AT DEATH:
29 September 1839, Agordo, Tyrol, Italy. Aged 68
DISCIPLINE:
Mineralogist
FIELD:
Mineralogy
PARENTS:
Father: ?
Mother: ?
SIBLINGS:
?
SPOUSE:
?
CHILDREN:
?
EDUCATION:
Privately at home
University of Halle
MAJOR WORK:
“Der Charaktere der Klassen, Ordnungen, Geschlecter, und Arten der naturhistorischen Mineral-Systems” (1820, “The Characters of the Classes, Orders, Genera and Species of the Natural-History System of Mineralogy”)
“Grand-Riss der Mineralogie” (1922-24, “Treatise on Mineralogy”)
LIFE AND TIMES:
Mohs was interested in science as a boy. He studied under <taught by> Werner* at the mining academy at Freiberg and graduated in 1789.
In 1802 he travelled to Britain at the invitation of English fellow students with the aim of setting up a mining academy in Dublin, Ireland. Although the project did not materialize, Mohs was able to undertake geological and mineralogical investigations in Ireland and Scotland.
On his return to Europe, he was commissioned by a Viennese banker to catalogue and describe his mineral collection and in 1804 he published the results of this investigation and other researches. In his treatise, Mohs showed that he was already going beyond Werner’s system of mineralogical analysis. When he met Werner at Carlsbad while on a field trip in 1810, Mohs discussed his ideas but he failed to convince Werner of the validity of the new methods he was proposing.
The following year Mohs was appointed curator of the mineral collection at the newly established Johanneum in Graz, and was also given a brief to add to the collection with material from Styria.
In 1812 he became professor mineralogy at the Johanneum. That year he suggested a hardness scale for minerals. He proposed a numbered scale of increasing hardness from talc at number one to diamond at number ten. This was an important advance in the quantitative data used for mineralogical analysis.
Mohs continued to refine his method of mineralogical classification, including the idea of crystallographical categorization based on possible arrangements of minerals in crystal systems based on external symmetry. In 1817 he left Graz and spent several months traveling in Britain where his new ideas were well received.
In 1818 he became professor mineralogy at Freiberg. Between 1822 and 1824 he produced his ideas on crystallographical classification and proposed four crystal systems based on external symmetry: rhombohedral (hexagonal), pyramidal (tetragonal), prismatic (orthorhombic) and tessular (cubic). His book was translated into English in 1825.
In the same year, Mohs was visited by the English natural scientist <visited by> Whewell* who had already published papers on crystallography and wanted to consult Mohs on his system of mineral classification.
However, Mohs’s new classification system, which was based mainly on crystal form, hardness and specific gravity, was not accepted by most geologists. In 1926 he left Freiberg to go to Vienna and organize the imperial mineral collection. In 1828 he became professor of mineralogy at the University of Vienna, a position he held until 1835 when he was appointed imperial counsellor of the exchequer in charge of mining and monetary affairs.
Mohs died in 1839 while inspecting the volcanic areas of southern Italy.
ASSESSMENT: Mohs was responsible for new quantitative classification systems for the categorization of minerals.
EXTRA CONNECTIONS: None
ONELINER: Freidrich Mohs, inventor of the hardness scale
BIBLIOGRAPHY:
Fritscher, Bernhard and Henderson, Fergus, Toward a History of Mineralogy, Petrology, and Geochemistry, Insitut fur Geschichte der Naturwissenschaften, Munich, 1998
DSB