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Esper S. Larsen, III

Esper "Ep" Signius Larsen, III (1912-1961) was born in Los Angeles, California on October 10, 1912, the son of a prominent Harvard mineralogist and petrographer. His early years were spent in Washington, DC and Belmont, Massachusetts, where his family moved when his father joined the faculty at Harvard. He entered Harvard himself in 1930, receiving his B.S. in 1934, M.A. in 1935, and PhD in 1940. He studied all of the physical sciences and while in Graduate School served as Professor L. C. Graton's assistant in ore microscopy.

Unfortunately a serious accident had left Larsen partially paralyzed and confined to a wheelchair, so he was unable to do field work. In 1938 Professor Harry Berman introduced him to Arthur Montgomery and suggested that Larsen examine the Fairfield minerals, an idea that he enthusiastically accepted for his doctoral dissertation, basing his work primarily on specimens collected by Arthur Montgomery and Edwin Over. This works resulted in several published papers: Larsen (1940) (describing overite and montgomeryite), Larsen and Montgomery (1940) (describing sterrettite), and Larsen (1942) (a comprehensive review of variscite nodule mineralogy in three parts).

In 1941 he married Marjorie Ann Esters of Belmont, Massachusetts. He also studied the nature of minerals responsible for silicosis and asbestos, then in 1942 joined the U.S. Geological Survey. His first work involved the preparation of geological reports for the Army Corps of Engineers, providing classified reports and maps for the military during World War II. In 1949 he was appointed head of the Petrology unit of the Geological Division of the U.S. Civil Service Commission, then took a position as Assistant Chief Geologist for Basic Research with the Geological Survey, a position he held with distinction until being compelled to retire following a severe heart attack. From 1954 until the time of his death he was involved in research on the geochemistry of uranium and thorium. He died suddenly of a heart attack on October 6, 1961, just a few days short of his 49th birthday, and seven months after the death of his father; their memorials appeared back-to-back in the American Mineralogist.

PECORA, W. T. (1962) Memorial of Esper Signius Larsen, 3rd. American Mineralogist, 47, 460-463.
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WILSON, Wendell E. (2019)
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