0.85g fragment with crust
Sold in membrane box with label/certificate of authenticity
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Northwest Africa 10153 (NWA 10153)
Purchased: 2014 Dec
Classification: Martian meteorite (Nakhlite)
History: Purchased by Darryl Pitt in December 2014 from a dealer in Erfoud, Morocco.
Physical characteristics: A single (119 g) somewhat friable stone lacking fusion crust. The interior appears granular and overall gray green in color, but with prominent beige to reddish brown interstitial components.
Petrography: (A. Irving and S. Kuehner, UWS) Cumulate texture. Large (up to 2.0 mm long) prismatic, compositionally zoned augite grains and subordinate, larger (2.2-3.0 mm), equant grains of olivine (with distinct ferroan rims) are the predominant constituents, along with interstitial birefringent plagioclase laths, chlorapatite, ulvöspinel, exsolved Fe-Ti oxide, plus an optically and compositionally heterogeneous iron silicate phase (red-brown in thin section) resembling chlorophaeite.
Geochemistry: Olivine (cores Fa61.3-63.7, rims Fa76.2-81.8, FeO/MnO = 41-48, N = 4), augite (Fs23.1-43.5Wo39.6-41.1, FeO/MnO = 31-38, N = 8), plagioclase (An23.4-25.4Or5.3-3.4, N = 3), chlorophaeite-like phase (average of 5 analyses in wt.%): SiO2 43.3, Al2O3 1.6, Fe2O3 36.0, MgO 2.0, CaO 1.0, Na2O 0.4, K2O 0.4. Oxygen isotopes (K. Ziegler, UNM): Analyses of three acid-washed subsamples by laser fluorination gave, respectively, δ17O 2.677, 2.870, 2.591; δ18O 4.579, 4.963, 4.446; Δ17O 0.259, 0.250, 0.244 per mil.
Classification: Martian meteorite (nakhlite).
Specimens: 22.3 g including one polished thin section and one polished thick section at UWB. The remaining material is held by DPitt.