Karl Cäsar von Leonhard (12 September 1779 – 23 January 1862) was a German

mineralogist Mineralogy is a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical (including optical mineralogy, optical) properties of minerals and mineralized artifact (archaeology), artifacts. Specific s ...

and

geologist A geologist is a scientist who studies the structure, composition, and History of Earth, history of Earth. Geologists incorporate techniques from physics, chemistry, biology, mathematics, and geography to perform research in the Field research, ...

. His son, Gustav von Leonhard, was also a mineralogist. From 1797 he studied at the universities of

Marburg Marburg (; ) is a college town, university town in the States of Germany, German federal state () of Hesse, capital of the Marburg-Biedenkopf Districts of Germany, district (). The town area spreads along the valley of the river Lahn and has ...

and

Göttingen Göttingen (, ; ; ) is a college town, university city in Lower Saxony, central Germany, the Capital (political), capital of Göttingen (district), the eponymous district. The River Leine runs through it. According to the 2022 German census, t ...

, where

Johann Friedrich Blumenbach Johann Friedrich Blumenbach (11 May 1752 – 22 January 1840) was a German physician, naturalist, physiologist and anthropologist. He is considered to be a main founder of zoology and anthropology as comparative, scientific disciplines. He has be ...

was an important influence to his career. He collected many mineralogical specimens on scientific excursions in

Saxony Saxony, officially the Free State of Saxony, is a landlocked state of Germany, bordering the states of Brandenburg, Saxony-Anhalt, Thuringia, and Bavaria, as well as the countries of Poland and the Czech Republic. Its capital is Dresden, and ...

and

Thuringia Thuringia (; officially the Free State of Thuringia, ) is one of Germany, Germany's 16 States of Germany, states. With 2.1 million people, it is 12th-largest by population, and with 16,171 square kilometers, it is 11th-largest in area. Er ...

, continued by travel to the

Austrian Alps The Central Eastern Alps (), also referred to as Austrian Central Alps () or just Central Alps, comprise the Main chain of the Alps, main chain of the Eastern Alps in Austria and the adjacent regions of Switzerland, Liechtenstein, Italy and Slov ...

(including the

Salzkammergut The Salzkammergut (, ; ) is a resort area in Austria, stretching from the city of Salzburg eastwards along the Alpine Foreland and the Northern Limestone Alps to the peaks of the Dachstein Mountains. The main river of the region is the Traun (r ...

). During his journeys he made the acquaintance of Friedrich Mohs and Karl von Moll. In 1818, through assistance from Baden minister of state Sigismund von Reitzenstein, he was appointed professor of mineralogy at the

University of Heidelberg Heidelberg University, officially the Ruprecht Karl University of Heidelberg (; ), is a public university, public research university in Heidelberg, Baden-Württemberg, Germany. Founded in 1386 on instruction of Pope Urban VI, Heidelberg is List ...

. In 1807 he founded the popular mineralogical journal "''Taschenbuch für die gesammte Mineralogie''" — after 1830 the publication was known as "''Neues Jahrbuch für Mineralogie, Geologie and Paläontologie''" (edited with

Heinrich Georg Bronn Heinrich Georg Bronn (3 March 1800 – 5 July 1862) was a German geologist and paleontologist. He was the first to translate Charles Darwin's '' On the Origin of Species'' into German in 1860, although not without introducing his own interpretat ...

). He was a founding member of the ''Wetterauischen Gesellschaft'' (

Wetterau The Wetterau (, ) is a fertile undulating tract, watered by the Wetter (river), Wetter, a tributary of the Nidda (river), Nidda River, in the western German state of Hesse, between the hilly province Oberhessen and the north-western Taunus mounta ...

Society). During his career, he maintained correspondence on mineralogical subjects with Leopold von Buch,

Johann Wolfgang von Goethe Johann Wolfgang (von) Goethe (28 August 1749 – 22 March 1832) was a German polymath who is widely regarded as the most influential writer in the German language. His work has had a wide-ranging influence on Western literature, literary, Polit ...

, Abraham Gottlob Werner and Johann Karl Wilhelm Voigt. In 1824 he introduced the term "

loess A loess (, ; from ) is a clastic rock, clastic, predominantly silt-sized sediment that is formed by the accumulation of wind-blown dust. Ten percent of Earth's land area is covered by loesses or similar deposition (geology), deposits. A loess ...

" into the geological science. Nowadays Leonhard is recognized as one of the key pioneers of

studies The term " leonhardite" bears his name, being defined as a partially dehydrated, opaque laumontite.

Selected works

* ''Systematisch-tabellarische Uebersicht und Charakteristik der Mineralkörper'', 1806 (with Johann Heinrich Kopp and Karl Friedrich Merz) – Systematic tabular overview and characteristics of the mineral body. * ''Bedeutung und Stand der Mineralogie'', 1816 – The importance and state of mineralogy. * ''Mineralogisch-chemische Untersuchungen des Triphan's und Tantalit's'', 1818 – Mineralogical-chemical studies of triphane and tantalite. * ''Handbuch der Oryktognosie'', 1821 – Handbook of mineralogy. *''Charakteristik der Felsarten'', 1824 – a catalogue of ground materials. * ''Die Basalt-Gebilde in ihren Beziehungen zu normalen und abnormen Felsmassen'', 1832 –

Basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...

formations in their relationship to normal and abnormal masses of rock. * ''Naturgeschichte des Mineralreichs'' (2 volumes, 1833) – Natural history of the mineral kingdom. * ''Lehrbuch der Geognosie und Geologie'', 1835 – Textbook of geognosy and geology. * ''Geologie, oder Naturgeschichte der Erde'' (5 volumes, 1836) – Geology; natural history of the Earth. * ''Agenda geognostica; Hülfsbuch für reisende Gebirgsforscher und Leitfaden zu Vorträgen über angewandte Geognosie'', 1838 – Geognostic agenda; hülfsbuch for mountain researchers and a guide to lectures on applied geology.

References

{{DEFAULTSORT:Leonhard, Karl Casar von 1779 births 1862 deaths People from Offenbach am Main University of Marburg alumni University of Göttingen alumni Academic staff of Heidelberg University 19th-century German geologists German mineralogists Members of the Göttingen Academy of Sciences and Humanities 18th-century German geologists