b'8 Carnegie Science|Fall 2019New Mineral Classification System Reveals Earths Complex PastA new classification system that accounts for minerals distinct journeyssuch as diamonds forming in the early universe from the first generation of exploding stars, or forming later deep within the Earthcould help us better understand mineralogy as a process of universal and planetary evolution.The first minerals to form in the universe were nanocrystalline diamonds. They condensed from gases ejected when the first generation of stars exploded. We are more familiar with diamonds that crystallize under the extreme pressure and temperatures deep inside the Earth. What opportunities for knowledge are lost when mineralogists categorize both the Most people are familiar with diamonds that crystallize under the extreme cosmic and deep Earth minerals as simplypressure and temperatures deep inside the Earth (left). However, the first diamond? minerals to form in the universe were nanocrystalline diamonds, which condensed from gases ejected from the first generation of exploded stars, The current system for classifyingsimilar to the exploding supernova 1987A shown (above).minerals was developed by James DwightImages courtesy iStockphoto.com/TomekD76 (left) and European Southern Observatory (above)Dana in the 1850s. It categorizes more than 5,400 mineral species based on theirTo better reflect the inherentcategory, while splitting others with dominant chemical compositions andmessiness of planetary evolution, Hazensimilar origin stories into separate crystalline structures. It is an unambiguous,explains, there could be a systemmineral species.robust, and reproducible scheme. grouping minerals and noncrystallineAnother example: currently 32 Carnegies Robert Hazen suggests annatural solids, which are not currentlydifferent mineral species of the additional classification system, whichclassified by the existing system, intotourmaline group are delineated by the could amplify existing knowledge of howwhat he calls natural kind clusters. distribution of the major elements of minerals evolve without superseding theFor maximum efficacy, scientificwhich they are comprised. So, a single existing designations. In Americanclassification systems must not justshard of tourmaline with slight variations Mineralogists organize and define but also reflectin chemistry often contains multipleRoebling Medal Paper, Hazen argues for categories that reflect acurrent theory and allow it to expand andspecies of the mineral, even if they all deeper, more-modern understanding ofguide us to new conclusions, he said. formed in the same geologic event.planetary-scale transformation over time.Hazen pioneered a concept of mineralA natural kind classification system evolution linking an explosion in mineralwould rectify that problem, and allow for diversity to the rise of life on Earth andthe inclusion of noncrystalline materials the resulting oxygen-rich atmosphere. Hesuch as volcanic glass, amber, and coal, then added another layer to his vision bywhich currently arent counted as introducing mineral ecology, whichminerals but can offer knowledge about analyzes the spatial distribution of Earthsour evolving planet.minerals to predict which ones remainEarths mineralogy tells vivid stories, undiscovered and to assert our planetsrevealing how eons of geologic activity and mineralogical uniqueness. the rise of life facilitated novel combinations A system of categorization thatof elements, Hazen argues. But to glean reflects not just a minerals chemistry andevery nuance of this mineralogical text, we crystalline structure, but also themust embrace a new language for physical, chemical, or biologicaldescribing the creation of minerals that processes by which it formed, would bereflects the passage of time.capable of recognizing that nanodiamonds from space are fundamentally different SUPPORT:from diamonds formed in Earths depths. This publication is a contribution to the Deep Carbon Staff scientist Robert Hazen investigates different aspects of the coevolving geosphere and biosphere,The existing classification systemObservatory. Studies of mineral evolution and mineral ecology are supported by the Deep Carbon Observatory, the Alfred P. Sloan particularly within Earths evolving mineralogy. groups some minerals with disparateFoundation, the W.M. Keck Foundation, the John Templeton Image courtesy Carnegie Institution for Science Foundation, the NASA Astrobiology Institute, a private formation histories together in onefoundation and the Carnegie Institution for Science.'