Northwest Africa 12003 (NWA 12003)

Morocco

Purchased: February 2018

Classification: Carbonaceous chondrite (CK6)

History: Purchased from Adam Aaronson during the Tucson Gem and Mineral show February 2018.

Physical characteristics: Dark-gray stone with darker gray/black crust covering about 60%. Stone shows evidence of sand polishing.

Petrography: (C. Herd and L. Tunney, UAb) Optical and microprobe examination of a polished thin section shows an unbrecciated texture consisting of sparse porphyritic olivine chondrules set in a recrystallized matrix of olivine, plagioclase, high-Ca pyroxene, Cr-Ti-bearing magnetite, and Fe-Ni sulfide. Nearly all sulfide and some silicate has been replaced by fine-grained oxides. Average chondrule size 0.73 ± 0.25 mm (n=17).

Geochemistry: (C. Herd and L. Tunney, UAb) Data obtained by EMP examination of carbon-coated thin section: Olivine Fa_32.7±0.3 (FeO/MnO=117, mean NiO=0.57 wt%, n=21); high-Ca pyroxene Fs_9.1±0.8Wo_46.5±0.8 (FeO/MnO=65, n=3); plagioclase An_38.9±7.6Or_2.8±1.3 (range An_28.6-50.1Or_1.4-5.4, n=7). Chromite mean Cr #=0.61, TiO₂ = 0.35 wt% (n=10).

Classification: CK6 chondrite

Specimens: Type specimen of 9.4 g, including one thin section, at UAb. M. Ouzillou 37.2 g.