Stone, achondrite, ureilite
TKW: 1,200 g
Half individual: 612.0 g
This is a beautiful half individual with a mirror-polished cut surface, showing a checkered pattern of bright yellow olivines and dark pyroxene grains. Along the grain boundaries, a spiderweb-like network of graphite and metal has developed. With 612 g, this hand specimen opens a window into the 4.55 Billion years distant past of our solar system.
Write up (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).