Northwest Africa 11411 (NWA 11411)

Morocco

Purchased: February 2013

Classification: Ureilite

History: Purchased from Moroccan meteorite dealer in 2013.

Physical characteristics: Physical Characteristics: Single stone with black/brown irregular weathered surface with small area of fusion crust. Saw cut shows dark interior with scattered reflective grains. Stone was extremely difficult to cut.

Petrography: (K. Domanik and F. Stephan, UAz) Microprobe examination of a polished mount reveals approx. 70% olivine, 26% pigeonite, with an average grain size of approx. 600-800 μm. Fe-Ni veins occupy grain boundaries most of which have been oxidized by desert weathering. Graphite, partially altered to diamond, is present along some grain boundaries as small domains 50-200 μm in size. Olivine grain boundaries in contact with metal veins or diamond are Mg-rich and contain extremely densely-packed tiny metal blebs, often coalescing into wide, mossy-textured haloes along vein edges, 100-150 μm in width.

Geochemistry: Mineral compositions and geochemistry: (K. Domanik and F. Stephan, UAz) Olivine cores Fa_20.8±0.9, Fe/Mn=42.2±4.5, Cr₂O₃=0.69±0.07 wt%, n=13; olivine rims Fa_2.6±1.0, Fe/Mn=5.3±2.0, Cr₂O₃=0.72±0.25 wt%, n=6; pigeonite Fs_17.8±0.2Wo_8.4±0.1, Fe/Mn=26.6±1.9, Cr₂O₃=1.15±0.03 wt%, n=12.

Classification: Achondrite (ureilite)

Specimens: 42.7 g plus one probe mount on deposit at UAz, Fredric Stephan holds the main mass.