Much of Robert Hazen’s scientific research has focused on the close relations between crystal structure and physical properties. He developed several high-pressure and high-temperature techniques and applied these techniques to understanding effects of temperature and pressure on atomic arrangements, particularly in deep-earth environments - work summarized in the monograph Comparative Crystal Chemistry (Wiley, 1982) and High-Temperature and High-Pressure Crystal Chemistry (co-edited with Robert Downs in 2000). He has studied a wide variety of materials, including lunar minerals, ceramics, ferroelectrics, solidified gases, and organometallics. Hazen led the team of Carnegie scientists who first isolated and identified several new high-temperature superconductor structure types.

In 1996, in collaboration with Robinson Professor Harold Morowitz, Hazen switched the focus of his research to study high-pressure organic synthesis and the origin of life. Working with a team of scientists at the Carnegie Institution, he developed a successful proposal to join NASA’s Astrobiology Institute to study the physical and chemical environments of high-pressure hydrothermal systems, and their possible role in prebiotic organic synthesis and the origin of life. Recent research projects include studies of mineral-mediated organic synthesis, the role of minerals in stabilizing organic compounds at extreme conditions, and the chiral selectivity of enantiomeric mineral surfaces. He is also active in the development of microanalytical tools for paleontology. Hazen also developed a two-semester graduate seminar “The Literature of Astrobiology” for George Mason’s astrobiology program.

Hazen joined the faculty of George Mason University as Clarence Robinson Professor of Earth Science in January 1989. He has been active in national efforts to reform science education, and has presented lectures and workshops on undergraduate science curricula at more than 100 colleges and universities. He served as a writer for the National Science Education Standards and has served on the Executive Board of the National Research Council’s Committee on Science Education and on the Committee for the Public Understanding of Science and Technology of the American Association for the Advancement of Science. His responsibilities at George Mason University include developing and teaching undergraduate courses in scientific literacy and in such interdisciplinary topics as “Symmetry in Arts and Sciences,” “The Image of the Scientist in Popular Culture” and “Scientific Ethics.”

In addition to his academic pursuits, Robert Hazen has played symphonic trumpet professionally since 1966. He studied in Boston with Natalo Paella, Andre Come, and Armando Ghitalla, and in Washington with Steven Hendrickson, Adel Sanchez, Chris Gekker and Emerson Head. He has appeared as soloist with the Boston Symphony Esplanade Orchestra, the National Gallery Orchestra, the Washington Handel Festival Orchestra, and on BBC TV in England. Hazen has given many recitals in the United States and Great Britain; in 1998 he appeared as soloist at the Kennedy Center with the Washington Chamber Symphony. He has performed with numerous ensembles in Europe and North America, including the Boston and National Symphonies, Orchestre de Paris, the New York, Boston, Washington, and Metropolitan Operas, and the Jeoffrey, American, Kirov, and Royal Ballets. He performs regularly with the National Gallery Orchestra, the Washington Bach Consort (on historic instruments), and the National Philharmonic, for which he is also a Board Member. Hazen has been recorded with ensembles on DDG, Pro Arte, New World, Nonesuch, Smithsonian and AMI records.

Hazen, frequently in collaboration with his wife Margaret Hindle Hazen, has written several books and many related articles on aspects of the history of American science and society. Previous works include American Geological Literature and North American Geology (a bibliography and review of early American geological research), Wealth Inexhaustible (a history of American mining and other mineral industries), and The Poetry of Geology (a collection of geological poetry of the 18th and 19th centuries). In 1987 he and Margaret Hazen completed The Music Men: An Illustrated History of Brass Bands in America (Smithsonian Institution Press, 1987), which received the 1989 ASCAP Deems Taylor Award. They subsequently wrote the script and appeared in a documentary film on the history of bands, produced by SIRS Inc. The Breakthrough: The Race for the Superconductor (Summit, 1988), is a non-technical account of the discovery of high-temperature superconductivity. The Hazens also wrote Keepers of the Flame (Princeton, 1990), a cultural and technological history of fire in early America, published by Princeton University Press in 1992. Hazen's books, The New Alchemists: Breaking Through the Frontiers of High-Pressure Research (Times Books, 1994) and The Diamond Makers (Cambridge University Press, 1999), explore the history of diamond making and other high-pressure applications. Why Aren't Black Holes Black: Unanswered Questions at the Frontiers of Science (Anchor, 1998), written with Maxine Singer, adopts the style of Science Matters, but focuses on the overarching questions that drive today's science.

In 1990 Hazen, with Robinson Professor of Physics James Trefil, wrote Science Matters: Achieving Scientific Literacy (Doubleday, 1991), which has almost 200,000 copies in print in a dozen languages. That volume proposes a definition of scientific literacy based on overarching scientific principles. In conjunction with the book Hazen has appeared on NBC’s The Today Show, CBS’s Nightwatch, WGBH (Boston) NOVA and numerous other national and local TV and radio programs. Hazen and Trefil also contributed articles and editorials to Newsweek, The New York Times Magazine, Chronicle of Higher Education, The Scientist, and other periodicals. Hazen and Trefil have also written three undergraduate textbooks that amplify these themes, The Sciences: An Integrated Approach (Wiley, 4th edition 2004), The Physical Sciences (Wiley, 1996), and Physics Matters (Wiley, 2004). The Sciences also served as the basis for Hazen’s 60-lecture video and audio course, “The Joy of Science,” distributed nationally by The Teaching Company. His 2005 book, Genesis: The Scientific Quest for Life's Origins, describes the work of fellow scientists (including Robinson Professor Harold Morowitz) in their efforts to understand the emergence of biological complexity from a geochemical world. In this book and a companion course, "The Origins of Life" produced by the Teaching Company, Dr. Hazen describes life's origins as a sequence of chemical steps, each of increasing complexity. Dr. Hazen was featured in an article in the Mason Gazette: http://gazette.gmu.edu/articles/11592 .