Cohen studied at the universities of
Berlin and
Heidelberg and from 1867 to 1872 was a
mineralogy assistant in the latter. He then spent 18 months in
South Africa, where he studied
diamond and
gold deposits. Cohen devoted his following years to mineralogy and drafting descriptions of his
African explorations. Through his
Sammlung von Mikrophotographien zur Veranschaulichung der mikroskopischen Structur von Mineralien und Gesteinen] (1881–83; "Collection of Microphotographs on the microscopic Structure of Minerals and Rocks"), he founded modern
petrography. In 1878 Cohen became
professor of petrography at
Strasbourg and Director of the Geological Survey for Alsace and Lorraine. In 1885 he was made professor of mineralogy at the
University of Greifswald. There he started work on meteorites, one of the first mineralogists to describe the petrography of
iron meteorites and their accessory minerals. Beside detecting diamonds, he isolated and analyzed an
iron carbide mineral there, later named
Cohenite for him. ==Publications==