Northwest Africa 18492 (NWA 18492) (Northwest Africa) Purchased: 2025 Classification: Ureilite History: Several fragments (total weigh 2500 g) were purchased by Mohamed Ali Loud from Buhali Ahmed Mohamed Salem in Nouadhibou, Mauritania, in 2025. Petrography: The meteorite exhibits a coarse-grained granoblastic texture with curvilinear crystal borders and well-developed 120° triple joints, dominated by olivine and orthopyroxene (up to 2.5-3.0 mm) with minor pigeonite. Olivine displays reduction rims associated with carbon blades. There are small Fe-rich pigeonite grains (50-60 µm) poikilitically enclosed within an olivine grain. Silicate crystals are bordered by large (up to 50-100 µm) FeNi network veins, nearly completely replaced by secondary iron oxy-hydroxides. A few fresh metallic patches reveal the presence of kamacite, Cr-rich taenite and Cr-sulfide. No plagioclase detected. Geochemistry: Olivine Fa13.3±3.9 (Fa6.0-17.6, FeO/MnO = 27.2±9.1, CaO 0.20-0.36 wt%, Cr2O3 0.52-0.85 wt% (N=23); orthopyroxene Fs16.2±0.4Wo4.5±0.1 (En78.4-80.0Fs15.7-17.0Wo4.3-4.8, FeO/MnO= 24.9±2.5, N=12), orthopyroxene in reduced rims Fs4.5±2.1Wo1.5±0.7 (En89.3-97.5Fs1.2-7.5Wo0.9-3.8, N=15); pigeonite Fs11.6±1.1Wo6.1±0.7 (En81.5-83.9Fs10.3-13.2Wo5.1-6.8, FeO/MnO= 16.4±5.1, N=6), Fe-rich pigeonite Fs73.9±5.7Wo6.0±0.6 (En15.7-24.6Fs69.9-77.8Wo5.6-6.4, N=2) Classification: Ureilite based on grain size, texture, reduced margins of olivines and mineral chemistry. Weathering grade: high Classifier: G. Pratesi, T. Cuppone, UniFi. This lot has no reserve price and comes with its certificate of authenticity. Thanks for your interest.