Half individual of the ureilite NWA 8168. The sample has one cut surfaces polished to 1500 grit. The original surface shows patches of fusion crust. This is the write up from Meteoritical Bulletin 104:
History: Discovered by local people in the NW area of Mauritania in 2012, purchased in Nouadhibou in 2012 Oct.
Physical characteristics: (R. Bartoschewitz, Bart) One brown fragment of 1200 g. Saw cut shows brown close packed grains. Magnetic susceptibility log χ (× 10-9 m3/kg) = 4.48.
Petrography: (R. Bartoschewitz, Bart) Microprobe examination of a thin section shows olivine and pyroxene grains with triple junctions, grain size 0.5-6 mm. Grain boundaries occupied with graphite and metal. Graphite occurs as elongated areas up to 2 × 7 mm.
Geochemistry: (R. Bartoschewitz, Bart, P. Appel and B. Mader, Kiel) Olivine: Fa21.0±2.0 (Fa14.7-22.1; Cr2O3=0.6-0.7 wt.%; Fe/Mn=44, n=15). Ca-poor pyroxene: Fs7.0 (n=1). Ca-rich pyroxene: Fs15En72Wo13 (n=26). Kamacite: Ni=5.0, Co=0.35, Si<0.3 wt.% (n=6).
October 4, 2015
Achondrites, Finds, Stones