Robert L. Folk

Robert "Bob" Louis "Luigi" Folk (September 30, 1925, Cleveland, Ohio – June 4, 2018) was an American geologist and petrologist, specializing in sedimentology, sandstone petrology, and carbonate petrology. He is known for the 1959 eponymous Folk classification of sedimentary rocks, which, with some minor modifications, is still in use today. He is one of the founders of what is sometimes called "Soft Rock Geology".