Johannes Leonhardt

This article deals with the mineralogist Johannes Leonhardt. For other people see Johann Leonhard .

Johannes Leonhardt (born April 8, 1893 in Neustädtel (Schneeberg) , † June 28, 1959 in Göttingen ) was a German mineralogist.

Leonhardt's father was active in mining so that he became interested in mineralogy and geology at an early age. In 1914 he was seriously wounded as a soldier in the First World War, was taken prisoner by the French and was exchanged via Switzerland in 1915. From 1917 he studied in Leipzig and received his doctorate in mineralogy under Friedrich Rinne in 1923 with a dissertation on X-ray crystallography of topaz and sodium hydrofluoride. From 1924 to 1929 he was a research assistant in the study society for electrical lighting (an institute of the Osram company at the University of Greifswald). From 1926 he held lectures and completed his habilitation in 1928 with a thesis on meteor irons. In 1929 he took over the management of the Mineralogical Institute in Kiel as a substitute and, after rehabilitation, became a non-civil servant professor in 1933. In 1939 he became a civil servant associate professor and in 1943 a full professor in Kiel and director of the Institute for Mineralogy and Petrography. There he set up an X-ray laboratory. The Mineralogical Institute, including its collection and library, was destroyed by an air raid on the night of August 26th to 27th, 1944. The already completed manuscript of a book about salt minerals and rocks by Leonhardt was destroyed (one copy in the institute, the other in his private apartment). Later he found no strength to rewrite (and his health was in poor health after the war). Since he was a member of the NSDAP and leader of the Gaudozenten, he was removed from office after the war. In 1948 he was again acting head of the institute and in 1950 again full professor and director. In 1958 he retired.

His students in Kiel included professors Ingeburg Schaacke , Werner Borchert (TH Munich), Waldemar Berdesinski (Heidelberg), Robert Kühn (honorary professor TH Munich), Werner Fischer (Marburg, Münster) and Hans-Heinrich Lohse (Marburg).

The magnesium sulfate mineral leonhardtite is named in his honor.

Web links

• Horst Küppers, On the history of mineralogy at the Christian-Albrechts-Universität zu Kiel, part 2, communications from the German Crystallographic Society, 2004, no. 28, p. 17, pdf