Sample No.: ALHA78108

Location: Allan Hills

Field No.: 399

Weight (gms): 172.5

Meteorite Type: H5 Chondrite

Physical Description:

Only the T and N surfaces of the specimen (6.0 x 5.5 x 4.0 cm) have remnant patches of fusion crust. The other surfaces of the specimen are fracture surfaces that have been weathered and stained by iron-oxidation. Several fractures are apparent on the exterior of the sample. This sample appears to be severely shocked. During chipping many slickenside surfaces were exposed. The sample is brecciated and two veins of black material (~1 mm wide) with higher relief that the surrounding material, are present in the interior of the stone.

Petrographic Description: Brian Mason

Chondritic structure is well developed, with chondrules ranging from 0.3-0.9 mm across. The chondrules are set in a fine-grained matrix which consists largely of olivine and pyroxene, with minor amounts of nickel-iron and troilite (nickel-iron in excess of troilite). Brown limonitic staining is present around the metal grains Microprobe analyses give the following compositions: olivine, Fa18; orthopyroxene, Fs16; plagioclase, An 12. The meteorite is classified as an H5 chondrite.