Sample No.: ALH82106 & ALH82130

Location: Allan Hills

Field No.: 2914 & 2994

Weight (gms): 35.1 & 44.6 Meteorite Type: Ureilite

Physical Description: Roberta Score

Patches of black fusion crust and remnant fusion crust cover much of these fragments. The interior surfaces are nearly black in color with moderate to heavy oxidation present. Well developed crystal faces are obvious. Samples appear to have been shocked. Dimensions: 4.5 x 2.5 x 2.5

Petrographic Description: Brian Mason

The section shows an aggregate of anhedral to subhedral grains (0.3-1.8 mm across) of olivine (about 60%) and pyroxene (about 30%), with about 10% of opaque material, in part disseminated throughout and in part concentrated along grain boundaries. Both olivine and pyroxene show undulose extinction; olivine grains are gray from submicroscopic opaque inclusions, where-as pyroxene grains are clear but are extremely fractured. The opaque material along grain boundaries consists of graphite and secondary iron oxides. Microprobe analyses give the following compositions: olivine, somewhat variable, Fa0-Fa5, mean Fa3; pyroxene, essentially uniform, Wo5Fs4En91; a grain of endiopside, Wo36Fs2En62, was analysed. The mineralogy and texture are typical of a ureilite, but the minerals in this meteorite have a higher Mg/Fe ratio than any ureilite so far described.  ALH82130 is essentially identical to ALH82106 in all respects and can confidently be paired with it.