title: Natural quasicrystal with decagonal symmetry.
abstract: We report the first occurrence of a natural quasicrystal with decagonal symmetry. The quasicrystal, with composition Al71Ni24Fe5, was discovered in the Khatyrka meteorite, a recently described CV3 carbonaceous chondrite. Icosahedrite, Al63Cu24Fe13, the first natural quasicrystal to be identified, was found in the same meteorite. The new quasicrystal was found associated with steinhardtite (Al38Ni32Fe30), Fe-poor steinhardtite (Al50Ni40Fe10), Al-bearing trevorite (NiFe2O4) and Al-bearing taenite (FeNi). Laboratory studies of decagonal Al71Ni24Fe5 have shown that it is stable over a narrow range of temperatures, 1120 K to 1200 K at standard pressure, providing support for our earlier conclusion that the Khatyrka meteorite reached heterogeneous high temperatures [1100 < T(K) ≤ 1500] and then rapidly cooled after being heated during an impact-induced shock that occurred in outer space 4.5 Gya. The occurrences of metallic Al alloyed with Cu, Ni, and Fe raises new questions regarding conditions that can be achieved in the early solar nebula.
authors.affiliation: Dipartimento di Scienze della Terra, Università di Firenze, Via La Pira 4, I-50121 Florence, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Bindi
authors.affiliation: Princeton Institute for the Science and Technology of Materials, Bowen Hall, Princeton University, Princeton, NJ 08544, USA.
authors.forename: Nan
authors.initials: N
authors.lastname: Yao
authors.affiliation: Department of Physics, Princeton University, Jadwin Hall, Princeton, NJ 08544, USA.
authors.forename: Chaney
authors.initials: C
authors.lastname: Lin
authors.affiliation: Department of Geosciences, Princeton University, Guyot Hall, Princeton, NJ 08544, USA.
authors.forename: Lincoln S
authors.initials: LS
authors.lastname: Hollister
authors.affiliation: Division of Earth and Atmospheric Sciences, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Andronicos
authors.affiliation: Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry (IGEM), Russian Academy of Sciences, Staromonetny per. 35, Moscow, 119017 Russia.
authors.forename: Vadim V
authors.initials: VV
authors.lastname: Distler
authors.affiliation: Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Eddy
authors.affiliation: Geoscience Technology, BHP Billiton, Houston, TX 77056, USA.
authors.forename: Alexander
authors.initials: A
authors.lastname: Kostin
authors.affiliation: Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry (IGEM), Russian Academy of Sciences, Staromonetny per. 35, Moscow, 119017 Russia.
authors.forename: Valery
authors.initials: V
authors.lastname: Kryachko
authors.affiliation: Department of Mineral Sciences, National Museum of Natural History, Smithsonian Institution, Washington DC. 20013, USA.
authors.forename: Glenn J
authors.initials: GJ
authors.lastname: MacPherson
authors.affiliation: Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, MA 02138, USA.
authors.forename: William M
authors.initials: WM
authors.lastname: Steinhardt
authors.affiliation: Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry (IGEM), Russian Academy of Sciences, Staromonetny per. 35, Moscow, 119017 Russia.
authors.forename: Marina
authors.initials: M
authors.lastname: Yudovskaya
authors.affiliation: 1] Department of Physics, Princeton University, Jadwin Hall, Princeton, NJ 08544, USA [2] Princeton Center for Theoretical Science, Princeton University, Princeton, NJ 08544 USA.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Steinhardt