It is with great sadness that we announce that Professor Dr. Wilhelm Johannes passed away on 18 June 2022 after a long and serious illness at the age of 86.

Wilhelm Johannes received his doctorate from the University of Marburg in 1963 and served as Senior Assistant at the University of Göttingen from 1964 to 1970. In 1970, he accepted a professorship in Petrology and Economic Geology at the Institute of Mineralogy of the then Technical University of Hannover, where he established the experimental petrology and geochemistry laboratories. This facility continues to enjoy an outstanding international reputation, providing unique opportunities to simulate processes in magma chambers under highly realistic conditions. His research included pioneering experimental studies on the stability of plagioclase feldspars, one of the most important mineral groups of the Earth's crust. He also made fundamental contributions to our current understanding of the formation of granites and migmatites. Wilhelm Johannes remained Professor at the Institute of Mineralogy of Leibniz University Hannover until his retirement in 2001.

We will remember him as a valued mentor and a cherished colleague.

François Holtz, Harald Behrens, Jürgen Koepke & Otto Dietrich