Donnel Foster Hewett (June 24, 1881, Irwin, Pennsylvania – February 5, 1971) was an American geologist and mineralogist, known for his leading role in the 1905 discovery of the Minas Ragra vanadium ore deposit in Peru.
After a year and a half there, he dropped out to attend a local business college and in the autumn of 1897 was employed for several months as a stenographer and typist before some more education in Washington, D.C.
[6] In 1903, after a year as an instructor in metallurgy and mineralogy at Lehigh University, Hewett became employed as a mining engineer for Pittsburgh Testing Laboratory,[6][3] a company known for pioneering research on aluminum and Portland cement.
[6] In 1909 he became a graduate student in geology at Yale University to study under his mentor and friend Joseph Barrell.
His 1st assignment, which lasted about 2 years, was to do fieldwork with Charles Thomas Lupton (1878–1935) in the coal fields of Wyoming's Big Horn Basin.
Hewett made important contributions to region's stratigraphy, discovered the Heart Mountain thrust fault, and demonstrated that bentonite is an alternation product of volcanic ash.
[3] In June 1921, the American Journal of Science published Hewett and Shannon's discovery of a new mineral found in Cuba's Oriente Province.
[3] In 1912 Hewett had been given responsibility for preparing a chapter on manganese for the USGS's annual publication on mineral resources of the United States.
Many influential people, including Franklin D. Roosevelt, believed those particular waters had outstanding healing properties for unknown reasons.
Hewett and Crickmay found that the spring waters had no exceptional physical or chemical properties and merely originated from rainfall that fell on a nearby mountain, went downward through a bed of permeable quartzite, and returned upward along a fault.
He and his wife settled in Pasadena, where Caltech offered him laboratory space, and from there he supervised and advised the USGS's mineral searches.
He worked with many specialists in sophisticated analytical techniques and shifted his headquarters to the USGS office in Menlo Park, California.