Sample No.: ALHA78053

Location: Allan Hills

Field No.: 267

Weight (gms): 179.0

Meteorite Type: H4 Chondrite

physical Description:

This 8.0 x 6.0 x 2.5 cm specimen has a small amount of thin, shiny black fusion crust on the B face. The remainder of the sample is smooth, weathered and stained reddish-brown by iron-oxidation. Fractures are present on the T and B surfaces. No unweathered material was exposed in the meteorite during processing.

Petrographic Description: Brian Mason

Chondritic structure is well developed, with chondrules ranging from 0.3-1.1 mm across; the commonest types are porphyritic olivine (with turbid partly devitrified glass between the olivine crystals), granular olivine and olivine-pyroxene, and fine-grained pyroxene. The chondrules are set in a fine-grained granular groundmass of olivine and pyroxene, with minor amounts of nickel-iron and troilite. Some of the pyroxene is polysynthetically twinned clinobronzite. Brown limonitic staining pervades the section, and veinlets and patches of red-brown limonite are present. Microprobe analyses give the following compositions: olivine, Fa17; pyroxene, Fs16. The meteorite is classified as an H4 chondrite.