Robert Miller Hazen (born November 1, 1948) is an American mineralogist and astrobiologist. He is a research scientist at Carnegie Institution for Science's Earth and Planets Laboratory and Clarence Robinson Professor of Earth Sciences Emeritus at George Mason University, in the United States. Hazen launched the Deep Carbon Observatory in 2009 and served as its Executive Director until 2019.
Early life Hazen was born in Rockville Centre, New York, on November 1, 1948. His parents were Peggy Hazen (née Dorothy Ellen Chapin; 1918–2002) and Dan Hazen (né Daniel Francis Hazen, Jr.; 1918–2016). He spent his early childhood in Cleveland, near a fossil quarry where he collected his first trilobite at the age of about 9.
The Hazen family moved to New Jersey, where Robert's eight-grade teacher, Bill Welsh, observed Robert's interest in his collection of minerals. Hazen later recalled "He gave me a starter collection of 100 specimens, mineral field guides, and mimeographed directions to Paterson and Franklin, New Jersey." Hazen also had an early interest in music, starting with the piano at age 5, the violin at 6 and the trumpet at age 9.
Education Hazen worked on his B.S. and S.M. (Master of Science) in Earth Science at the Massachusetts Institute of Technology 1971. He started with the intention of going into chemical engineering, but he was captivated by the enthusiasm of David Wones and converted to mineralogy. With Wones as advisor, he completed a masters thesis on cation substitution in trioctahedral micas; his publication in American Mineralogist was his first to be highly cited. He completed a Ph.D. in Mineralogy & Crystallography at Harvard University in 1975. His thesis, with Charles Burnham as advisor, involved learning how to use a 4-circle diffractometer to do high-pressure X-ray crystallography and applying it to olivine. This became a focus of his early career.
While a NATO Postdoctoral Fellow at Cambridge University in England, Hazen worked with Charles Prewitt to determine empirical relations for the effect of temperature and pressure on interatomic distances in oxides and silicates.
Geophysical Laboratory In 1976, Hazen joined the Carnegie Institution's Geophysical Laboratory as a research associate. After a brief stint measuring optical properties of lunar minerals with Peter Bell and David Mao, he started to do X-ray crystallography with Larry Finger. He later recalled, "It was a match made in mineralogical heaven: Larry loved to write code, build machines, and analyze data; I loved to mount crystals, run the diffractometers, and write papers." They collaborated for two decades and determined about a thousand crystal structures at variable pressures and temperatures, work summarized in their 1982 book Comparative Crystal Chemistry.
Much of the work that Hazen was doing could be classified as mineral physics, a cross between geophysics and mineralogy. Although the field had pioneering contributions from the Nobel Prize winner Percy Bridgman and a student of his, Francis Birch, in the early- to mid-20th century, it did not have a name until the 1960s, and in the 1970s some scientists were concerned that a more interdisciplinary approach was needed to understand the relationship between interatomic forces and mineral properties. Hazen and Prewitt co-convened the first mineral physics conference; it was held on October 17–19, 1977 at the Airlie House in Warrenton, Virginia.
High-temperature superconductors
Cooled to very low temperatures, some materials experience a sudden transition where electrical resistance drops to zero and any magnetic fields are expelled. This phenomenon is called superconductivity. Superconductors have a host of applications including powerful electromagnets, fast digital circuits and sensitive magnetometers, but the very low temperatures needed make the applications more difficult and expensive. Until the 1980s, no superconductors existed above . Then in 1986 two IBM researchers, Georg Bednorz and K. Alex Müller, found a ceramic material with a critical temperature of . This set off a frenzied search for higher critical temperatures.
A group led by Paul Chu at the University of Houston explored some materials made of yttrium, barium, copper and oxygen (YCBO) and were the first to obtain a critical temperature above the boiling point of liquid nitrogen. The YCBO samples had a mixture of black and green minerals, and although the researchers knew the average composition, they did not know the compositions of the two phases. In February 1987, Chu turned to Mao and Hazen, because they could determine the composition of small mineral grains in rocks. It took Hazen and Finger a week to determine the compositions; the black phase, which turned out to be the superconductor, was YBa2Cu3O7−δ.
Hazen, Finger, and colleagues determined that the crystal structure of the superconducting phase was like that of perovskite, an important mineral in Earth's mantle. Subsequently, Hazen's group identified twelve more high-temperature oxide superconductors, all with perovskite structures, and worked on organic superconductors.
Origins of life
By the mid-1990s, Hazen felt that his research had reached a "respectable plateau" where the main principles of how crystals compress were known. The questions he was asking were increasingly narrow and the answers rarely surprising. So he changed research directions to study life's chemical origins. This opportunity came when a colleague at George Mason University, Harold Morowitz, realized that the temperature and pressure at a hydrothermal vent might change the properties of water, allowing chemical reactions that ordinarily require the help of an enzyme. Enlisting the help of Hatten Yoder, a specialist in high pressure mineralogy, they tried subjecting pyruvate in water to high pressure, hoping for a simple reaction that would return oxaloacetate. Instead, an analysis by an organic geochemist, George Cody, found that they obtained tens of thousands of molecules.
The publication of their results, which seemed to support the deep sea vent hypothesis, met with criticism, especially from Stanley Miller and colleagues who believe that life emerged on the surface. Along with the general criticism that organic compounds would not survive long in hot, high pressure conditions, they pointed out several flaws in the experiment. In his book, Genesis, Hazen acknowledges that Stanley Miller "was basically right" about the experiments, but argues that "the art of science isn't necessarily to avoid mistakes; rather, progress is often made by making mistakes as fast as possible, while avoiding making the same mistake twice." In subsequent work, the group formed biomolecules from carbon dioxide and water and catalyzed the formation of amino acids using oxides and sulfides of transition metals; and different transition elements catalyze different organic reactions.
Homochirality
Organic molecules often come in two mirror-image forms, often referred to as "right-handed" and "left-handed". This handedness is called chirality. For example, the amino acid alanine comes in a right-handed (D-alanine) and a left-handed (L-alanine) form. Living cells are very selective, choosing amino acids only in the left-handed form and sugars in the right-handed form. However, most abiotic processes produce an equal amount of each. Somehow life must have developed this preference (homochirality); but while scientists have proposed several theories, they have no consensus on the mechanism.
Hazen investigated the possibility that organic molecules might acquire a chiral asymmetry when grown on the faces of mineral crystals. Some, like quartz, come in mirror-image forms; others, like calcite, are symmetric about their centers but their faces come in pairs with opposite chirality. With Tim Filley, an expert at organic chemical analysis, and Glenn Goodfriend, a geochemist, Hazen cleaned large calcite crystals and dipped them into aspartic acid. They found that each face of the crystal had a small preference for either left- or right-handed forms of aspartate. They proposed that a similar mechanism might work on other amino acids and sugars. This work attracted a lot of interest from the pharmaceutical industry, which needs to produce some of their drugs with a pure chirality.
Mineral evolution
At a Christmas party in 2006, the biophysicist Harold Morowitz asked Hazen whether there were clay minerals during the Archean Eon. Hazen could not recall a mineralogist ever having asked whether a given mineral existed in a given era, and it occurred to him that no one had ever explored how Earth's mineralogy changed over time. He worked on this question for a year with his closest colleague, geochemist Dimitri Sverjensky at Johns Hopkins University, and some other collaborators including a mineralogist, Robert Downs; a petrologist, John Ferry; and a geobiologist, Dominic Papineau. The result was a paper in American Mineralogist that provided a new historical context to mineralogy that they called mineral evolution.
Based on a review of the literature, Hazen and his co-authors estimated that the number of minerals in the Solar System has grown from about a dozen at the time of its formation to over 4300 at present. (As of 2026, the latter number has grown to 6239.). They predicted that there was a systematic increase in the number of mineral species over time, and identified three main eras of change: the formation of the Solar System and planets; the reworking of crust and mantle and the onset of plate tectonics; and the appearance of life. After the first era, there were 250 minerals; after the second, 1500. The remainder were made possible by the action of living organisms, particularly the addition of oxygen to the atmosphere. This paper was followed over the next few years by several studies concentrating on one chemical element at a time and mapping out the first appearances of minerals involving each element.
Deep Carbon Observatory In 2008, the Alfred P. Sloan Foundation provided an initial grant to support a 10-year international program—the Deep Carbon Observatory—to study Earth’s carbon cycle from crust to core, with special emphasis on four scientific themes: deep life, reservoirs and fluxes, deep energy, and extreme physics and chemistry. The program, with Hazen as Principal Investigator and Executive Director, eventually enlisted 1300 scientists from 55 countries.
Hazen and his colleagues started the Carbon Mineral Challenge, a citizen science project dedicated to accelerating the discovery of "missing" carbon-bearing minerals. This effort eventually resulted in the discovery of 31 new carbon-bearing minerals.
Teaching