Émile Bertrand (1844–1909) was a French mineralogist, in honour of whom bertrandite was named by Alexis Damour.[1] He also gave his name to the Bertrand lens or phase telescope.
He studied at the Ecole des Mines in Paris and was a co-founder of the Société française de minéralogie et de cristallographie.[1] He wrote a book on the application of microscopy to mineralogical studies, "De l'Application du microscope à l'étude de la minéralogie" (1878);[2] published a translation of Ernst Mach's work on the history of mechanics, "La mécanique: exposé historique et critique de son développement" (1904);[3] and is credited with the design of a refractometer.[4]