El Médano 496 (EM 496)        24°37.044’S, 70°18.414’W

Antofagasta, Chile

Find: 2019 Nov 20

Classification: Ordinary chondrite (L5)

History: While searching for meteorites, Vincent Stelluti recovered this stone on a slope of about 5% and composed of gravel, stones and sand. The stone was sunk into the ground about 2 cm.

Physical characteristics: A brown to dark brown stone with a roughly conical shape but with part of the cone missing. Fusion crust covers about 60% of the surface, with some regmaglypts and several cracks present. Physical properties: Bulk density: 3.38±0.03 g/cm3; Grain density: 3.35 ± 0.01 g/cm3; porosity zero; magnetic susceptibility log χ (× 10^-9 m³/kg) = 4.65.

Petrography: Cut surfaces show metal distributed in blebs and veins of cm length. In polished thin section, chondrules are poorly discernable and matrix is recrystallized; silicates show pervasive Fe-staining. Chondrules are typically fragmented with few complete. Thin dark veins with sharp contacts connect between localized dark patches that appear to be melt pockets in the silicates. Metal occurs interstitially between silicates or in small veins. Olivine shows mosaic extinction and planar fractures.

Geochemistry: EPMA: olivine Fa_24.66±0.50 (n=13); Ca-poor pyroxene Fs_20.62±0.56Wo_1.48±0.40 (n=5); Ca-poor pyroxene Wo_44.97±0.84Fs_8.01±1.19 (n=3)

Classification: Ordinary chondrite: L5 (S4) W2. Olivine and metal textures, as well as presence of melt pockets and shock veins are consistent with moderate to high shock metamorphism.

Specimens: Type specimen: UWO; Main mass V. Stelluti