Sample No.: ALHA78075

Location: Allan Hills

Field No.: 253

Weight (gms): 280.6

Meteorite Type: H5 Chondrite

Physical Description:

A thin, shiny fusion crust covers most of this specimen (7 x 6 x 3 cm), with the exception of portions of the T and W faces. The surfaces devoid of fusion crust are smooth and weathered to a shiny dark reddish-brown. Several non-penetrating fractures are present on the sample. Light colored inclusions and metal fragments are apparent in the dark matrix material of the sample.

Petrographic Description: Brian Mason

Chondritic structure is well developed, with chondrules ranging from 0.2-1.5 mm across; they include a variety of types, the commonest being porphyritic olivine, granular olivine, and fibrous radiating pyroxene. The groundmass consists largely of fine-grained olivine and pyroxene, with minor amounts of nickel-iron and troilite (nickel-iron in excess of troilite). Brown limonitic staining pervades the section and some veinlets and patches of red-brown limonite are present. Microprobe analyses give the following compositions: olivine, Fa18, pyroxene, Fs16. The meteorite is classified as an H5 chondrite.