Achille Delesse

Achille Ernest Oscar Joseph Delesse (3 February 1817 – 24 March 1881)[1] was a French geologist and mineralogist.

At the age of twenty he entered the École polytechnique, and subsequently went to the Ecole des Mines, where he was trained under the tutelage of Jean-Baptiste Élie de Beaumont and Ours-Pierre-Armand Petit-Dufrénoy.

[4] In early years as ingénieur des mines, Delesse investigated and described various new minerals; he proceeded afterward to the study of rocks, devising new methods for their determination, and giving particular descriptions of melaphyre, arkose, porphyry, syenite, and others.

His observations on the lithology of the deposits accumulated beneath the sea were of special interest and importance.

[4] Delesse was elected as a member to the American Philosophical Society in 1863, and to the French Academy of Sciences in 1879.