Northwest Africa 11409 (NWA 11409)

Morocco

Purchased: February 2013

Classification: Ureilite

History: Purchased from Moroccan meteorite dealer in 2013.

Physical characteristics: Physical Characteristics: Three stones exhibiting black irregular surfaces. Saw cut shows dark greenish-brown coarse grains separated by thin reflective veins.

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. Numerous oxidized Fe-Ni veins 5-30 μm wide occupy grain boundaries and also crosscut some grains. The veins contain a number of large irregularly shaped lenses of graphite, partially altered to diamond, 500-1500 μm long and 30-100 μm wide. In a few cases olivine grain boundaries in contact with larger metal veins or with diamond display a thin, discontinuous, Mg-rich rim, 2-10 μm wide, containing scattered, tiny (<2um) metal blebs. Pyroxene consists entirely 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_21.3±1.5, Fe/Mn=46.4±6.7, Cr₂O₃=0.64±0.10 wt%, n=16; olivine rims Fa_2.2±0.8, Fe/Mn=7.3±2.7, Cr₂O₃=0.42±0.14 wt%, n=11; pigeonite Fs_17.2±2.3Wo_7.9±0.9, Fe/Mn=24.9±4.5, Cr₂O₃=1.16±0.05 wt%, n=9; low-Ca pyroxene Fs_13.5±0.7Wo_2.7±0.4, Fe/Mn=24.7±5.7, Cr₂O₃=0.94±0.09 wt%, n=4.

Classification: Achondrite (Ureilite)

Specimens: 5.2 g plus three probe mounts on deposit at UAz, UAz holds the main mass.