Northwest Africa 11410 (NWA 11410)

Morocco

Purchased: February 2013

Classification: Ureilite

History: Purchased from Moroccan meteorite dealer in 2013.

Physical characteristics: Physical Characteristics: Single large stone, black irregular surface with remnant fusion crust. Saw cut shows dark mosaicized interior with dark green and smaller white grains. Stone was extremely difficult to cut.

Petrography: (K. Domanik and F. Stephan, UAz) Microprobe examination of a polished mount shows approx. 80% olivine and 15% pyroxene. The average grain size of both olivine and pyroxene is approx. 1-2 mm. Fe-Ni veins, now mostly oxidized by desert weathering, occupy grain boundaries and also crosscut some grains. The veins contain irregularly shaped patches of graphite, partially altered to diamond, 200-1000 μm in length. In rare cases olivine grain boundaries in contact with larger metal veins or with graphite display a thin, reduced rim, 2-10 μm wide, containing scattered, tiny metal blebs. Pyroxene consists of a patchy, mottled mixture of pigeonite and low-Ca pyroxene containing abundant void spaces, scattered Fe-metal blebs, and small Si-rich inclusions.

Geochemistry: Mineral compositions and geochemistry: (K. Domanik and F. Stephan, UAz) Olivine cores Fa_20.9±1.6, Fe/Mn=44.3±4.4, Cr₂O₃=0.66±0.07 wt%, n=17; olivine rims Fa_3.6±1.4, Fe/Mn=8.6±4.6, Cr₂O₃=0.57±0.10 wt%, n=8; pigeonite Fs_16.4±0.4Wo_9.6±1.0, Fe/Mn=24.7±1.9, Cr₂O₃=1.22±0.07 wt%, n=12; low-Ca pyroxene Fs_14.2±0.6Wo_2.9±0.4, Fe/Mn=26.7±3.4, Cr₂O₃=1.01±0.04 wt%, n=14.

Classification: Achondrite (ureilite)

Specimens: 20.2 g plus two probe mounts on deposit at UAz, Fredric Stephan holds the main mass.