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Northwest Africa 2517
Boudnib area, Morocco
Found 2004
Achondrite (ureilite)
One completely crusted stone weighing 17.6 g was purchased in Erfoud in 2004 September. Classification and mineralogy (M. Bourot-Denise, MNHNP): olivine crystals are mm-sized, with edges blackened by ribbons of sulfide associated with metal. Alteration is evident at grain boundaries. Metal and sulfide are intergrown. Pyroxene is in large, fissured crystals with cleavage planes blackened by fine sulfide blebs. Silicate crystals are abutting to each other practically without any interstitial material. Olivines are zoned, with a composition varying from Fa~1.4 at the edge up to Fa~22 at the center; mean at the center Fa22.6 ± 0.2, 0.5 wt% Cr2O3, 0.3 wt% CaO; pyroxene (pigeonite) Fs19.0 ± 0.6 Wo8.9 ± 1.6, 1.2 wt% Cr2O3. Magnetic susceptibility 4.35 (J. Gattacceca, CEREGE, Aix en Provence). Estimated shock stage S4, weathering grade W2. |
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