Sample No.: ALHA77217

Location: Allan Hills

Field No.: 77122948

Weight (gms): 413.2

Meteorite Type: L3 Chondrite

Physical Description:

This stone is approximately 9.5 x 7.0 x 4.5 cm. Fusion crust (~1 mm thick) covers approximately 20% of the sample. The remaining surfaces are covered with iron oxide stain. The S surface is only lightly stained, presumably this is the most recently exposed surface. The broken surfaces show distinct clasts, ranging from white to dark gray, as much as 1.5 cm in length. The stone is extremely heterogeneous on a centimeter scale. This is very similar in appearance to ALHA77216, ALHA77215, and ALHA77252.

Petrographic Description: Brian Mason

The thin section shows moderately abundant chondrules set in a granular groundmass consisting largely of olivine and pyroxene, with minor subequal amounts of nickel-iron and troilite. Much of the pyroxene, especially in the chondrules, is poly-synthetically twinned clinopyroxene. A little limonitic staining is present around nickel-iron grains. Microprobe analyses show some variability in olivine and pyroxene compositions: olivine, Fa17-Fa26, average Fa22; pyroxene Fs9-Fs26, average Fs17. The meteorite is classified as an L3 chondrite.