Sample No.: ALHA78153

Location: Allan Hills

Field No.: 492

Weight (gms): 151.7

Meteorite Type: LL6 Chondrite

Physical Description:

Fusion crust is present on the N, B and portions of the E surfaces. The fusion crust is thick (1-2 mm.) and dull brownish-black, and has a blistery texture. Many polygonal fractures are present. A weathering rind (as great as 5 mm thick is present in some areas. The fracture surfaces are dark brown in isolated areas, but the overall color is greenish-yellow. It appears that some large clasts have been plucked from the exterior surfaces of the sample. The sample shows an unusual weathering pattern. Veins of dark reddish-brown are adjacent to areas of yellowish material. Also areas of less severely weathered matrix material, which is gray, was exposed during processing of the sample. No clasts or chondrules are discernible.

Petrographic Description: Brian Mason

Chondritic structure is barely discernible the section showing a rather uniform granular aggregate of olivine and pyroxene with minor amounts of troilite and plagioclase, a little nickel-iron, and accessory chromite. A little limonitic staining is present in association with the metal grains. Microprobe analyses give the following composition: olivine, Fa29; orthopyroxene, Fs24; plagioclase, An11; and a single grain of diopside, Wo46En45Fs9. The meteorite is classified as an LL6 chondrite.