Auguste Michel-Lévy

Auguste Michel-Lévy was a French geologist, born in Paris in 1844, who became inspector-general of mines and director of the Geological Survey of France. He was distinguished for his researches on extrusive rocks and their microscopic structure and origins, and he was an early user of the polarizing microscope for identifying minerals. He pioneered the use of birefringence to identify minerals in thin section and is widely known for the Michel-Lévy interference colour chart. He also created classification schemes for igneous rocks that accounted for their mineralogy, texture and composition, and showed that rocks of different mineralogies could form from the same chemical composition under different conditions of crystallization. He wrote Structures et classification des roches éruptives in 1889, worked with Ferdinand André Fouqué on the artificial production of minerals and on Minéralogie micrographique, and worked with Alfred Lacroix on Les Minéraux des roches. He died in 1911.