Northwest Africa 4459
Algerian-Moroccan border
Find: June 2006
Ordinary chondrite (L3)

History: The sample was purchased in Erfoud by P. Thomas in June 2006.

Physical characteristics: A complete stone of 60.07 g, entirely covered with a very thin, slightly reddish, fusion crust.

Petrography: (M. Bourot-Denise, MNHNP) Sample displays a typical chondritic texture with small, round chondrules (100–200 μm in size) the major component. Matrix is abundant, little altered, and contains small metal grains. Large, rounded metal-sulfide nodules, which are slightly deformed and quite weathered occur in the matrix between chondrules. In BSE images the chondrite appears unequilibrated. Type I porphyritic chondrules contain FeO-poor olivines and low-Ca pyroxene, and FeO-rich silicates are only found in type II chondrules.

Geochemistry: Olivine, Fa12.0 ± 11.4, range Fa0.49–39.6, CaO up to 0.39, Cr2O3 in the range 0.11–0.76 (wt%); Low-Ca pyroxene, Fs7.7 ± 8.2, range Fs1.15–26.1. Magnetic susceptibility (J. Gattacceca, CEREGE) logχ = 4.32 (10-9 m3/kg) is consistent with an altered L chondrite.

Classification: Ordinary chondrite (L3, estimated subtype 3.3), weathering grade W3, shock stage S2.