Chi Ma*, John R. Beckett and George R. Rossman
Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, U.S.A.
During a nanomineralogy investigation of the Allende meteorite with analytical scanning electron microscopy, two new minerals were discovered; both occur as micro- to nano-crystals in an ultrarefractory inclusion, ACM-1. They are allendeite, Sc4Zr3O12, a new Sc- and Zr-rich oxide; and hexamolybdenum (Mo,Ru,Fe,Ir,Os), a Mo-dominant alloy. Allendeite is trigonal, R3̄, a = 9.396, c = 8.720, V = 666.7 Å3, and Z = 3, with a calculated density of 4.84 g/cm3 via the previously described structure and our observed chemistry. Hexamolybdenum is hexagonal, P63/mmc, a = 2.7506, c = 4.4318 Å, V = 29.04 Å3, and Z = 2, with a calculated density of 11.90 g/cm3 via the known structure and our observed chemistry. Allendeite is named after the Allende meteorite. The name hexamolybdenum refers to the symmetry (primitive hexagonal) and composition (Mo-rich). The two minerals reflect conditions during early stages of the formation of the Solar System. Allendeite may have been an important ultrarefractory carrier phase linking Zr-,Sc-oxides to the more common Sc-,Zr-enriched pyroxenes in Ca-Al-rich inclusions. Hexamolybdenum is part of a continuum of high-temperature alloys in meteorites supplying a link between Os- and/or Ru-rich and Fe-rich meteoritic alloys. It may be a derivative of the former and a precursor of the latter.
Reference
Ma C, Beckett JR and Rossman GR (2014) Allendeite (Sc4Zr3O12) and hexamolybdenum (Mo,Ru,Fe), two new minerals from an ultrarefractory inclusion from the Allende meteorite. American Mineralogist 99:654.
[doi:10.2138/am.2014.4667]
Copyright: The Mineralogical Society of America
Cosmochemistry Papers 