Steven B Shirey

✦ These types of rough diamonds, besides being the world's most valuable gemstones based on size and clarity, are remarkable for geological reasons.  Research done at the Gemological Institute of America by Evan Smith and the Carnegie Institution for Science by Steve Shirey, Peng Ni, Anat Shahar, Emma Bullock, and Jianhua Wang shows them to crystallize in the mantle transition zone (440-660 km deep) and to carry metallic inclusions. The iron in the inclusions was derived from magnetite and awaruite crystallized during serpentinization of peridotite on the ocean floor before being carried to great depth by subduction. See: Smith, E.M., Peng, N., Shirey, S.B., Richardson, SH., Wang, W., and Shahar, A. (2021) Heavy iron in large gem diamonds traces deep subduction of serpentinized ocean floor. Science Advances 7: eabe9773 https://doi.org/10.1126/sciadv.abe9773

Photo above is by Robert Weldon. © 2015 GIA. Courtesy of Gem Diamonds Ltd. This group of type IIa rough diamonds (VRL# 190894) shown here range from 14 to 91 carats and sometimes appear to be broken fragments of once larger diamonds. 

Interests and education

    A geologist for more than 50 years, since 1985 Steve Shirey has been a scientific staff member of the Geochemistry and Cosmochemistry Group at the Carnegie Institution for Science. His main interests are in diamonds as the deepest probe of plate tectonics, the igneous evolution of the Earth, and the emergence of Earth's continents. 

      Steve conducts his own research in these areas but equally important is the teaching and training he does of young scientists for their research careers. Over his career he has advised some 36 postdoctoral fellows and 24 PhD students, who have gone on to successful careers as university professors or in industry. 

     Steve is a Fellow of the American Geophysical Union (AGU), the Geochemical Society, the Geological Society of America, and the Mineralogical Society of America (MSA). He was 96th President of MSA and the 100th President of the Geological Society of Washington. He is the recipient the 2025 Harry H. Hess Medal  given by AGU in recognition of outstanding achievements in research on the constitution and evolution of the Earth and other planets. See the Carnegie press release here.

      He was educated at these institutions:

BA, Geology (1972), Dartmouth College

MS, Geology (1975), University of Massachusetts Amherst

PhD, Geochemistry (1984), Stony Brook University

Postdoctoral Fellow, Isotope Geochemistry (1984-1985), Carnegie Institution for Science

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Home institution

     The  Earth and Planets Laboratory (EPL) is one of the three divisions that make up the Carnegie Institution for Science —the nation's oldest, privately-endowed, research organization dedicated to fundamental scientific research for the benefit of mankind. The EPL (established 2019) is a combination of the former Geophysical Laboratory (established 1904) and the Department of Terrestrial Magnetism (established 1902). 

     At EPL, research in geophysics, seismology, volcanology, geochemistry, cosmochemistry, astronomy, planetary science, experimental petrology, mineral physics, and material science is carried out on one campus in residential northwest Washington, DC by ~50 resident scientists (25 staff scientists and 25 postdoctoral fellows). 

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Research environment

     The geochemists and cosmochemists of EPL where Steve works are historians of the evolution of Earth and the Solar System over the last ~4.6 billion years with a 40+ year record of making novel discoveries. Our thermal ionization, secondary ion, and inductively-coupled plasma mass spectrometers permit isotope ratio measurements at today’s limits of sensitivity, precision, and accuracy. They are an ensemble of tools whose powers we train on solid Earth samples and tiny remnants of the Solar System delivered by meteorites and asteroid missions. 

     Collectively, these instruments are a type of planetary observatory that operates much like an astronomical observatory does. Both observatories are “time machines”, to be aimed at and focused on a wide array of scientific problems. Our mass spectrometers allows us to look back in geologic time to earlier Eras in Earth history and back beyond Earth’s creation. The possible science is limited only by the imagination as to the targets choosen and the questions posed.