El Médano 499 (EM 499)        24°44.607’S, 70°21.165’W

Antofagasta, Chile

Find: 2019 Nov 23

Classification: Ordinary chondrite (L5-6)

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

Physical characteristics: A 202.6 g individual with six very unequal faces; four of the faces are relatively smooth and retain a very eroded dark brown fusion crust. Two other faces are broken and rough with a few throughgoing cracks; all faces have mature desert polish. Physical properties: Bulk density: 3.38±0.03; Grain density: 3.38±0.01; porosity zero; magnetic susceptibility log χ (× 10^-9 m³/kg) = 4.43.

Petrography: Cut faces show a brown weathered matrix, with dispersed metal grains, in a bulk rock that has dark veins separating blocks of chondritic meteorite. In thin section, local sharp dark veins cut across chondrules, and dark, arcuate veins subdivide the chondritic rock into sub-cm blocks, including one which appears to be of higher grade. Olivine shows undulatory extinction. Chondrules can be discerned but matrix is recrystallized.

Geochemistry: EPMA: olivine Fa_25.40±0.50 (n=15); Ca-poor pyroxene Fs_21.07±0.09Wo_1.34±0.23 (n=8)

Classification: Ordinary chondrite: L5-6 (S3) W2. Sparse metal and chondrules with moderate to poor definition in a recystallized matix suggests L5. Olivine EPMA limited range of compositions is consistent with L5. Clasts are of higher grade L6.

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