Sample No.: ALHA77009

Location: Allan Hills

Field No.: 77122943

Weight (gms): 235.5

Meteorite Type: H4 Chondrite

Physical Description:

This is a complete specimen with fusion crust missing only on the corners and one small area on the T surface. The fusion crust, where present, is approximately 0.5 mm thick and black. On the surfaces not covered by fusion crust, many weathered inclusions are present. An ~0.5 cm green inclusion, that appears to radiate, is present on the T surface. Much of the interior of the sample has weathered to a reddish-brown. Dimensions: ~6.5x4.5x4.3 cm.

Petrographic Description: Brian Mason

Chondritic structure is prominent. The usual variety of chondrule types is present, the commonest being barred olivine, granular olivine, and fine-grained radiating pyroxene. In a few of the barred chondrules the bars between the olivine are transparent brown glass, but in most the bars are turbid and devitrified. Some of the pyroxene is polysynthetically twinned clinobronzite. The groundmass between the chondrules consists of granular olivine and pyroxene, with minor amounts of nickel-iron and troilite. Remnants of fusion crust are present on one edge of the section. Microprobe analyses show olivine (Fa18) and pyroxene (Fs16) of essentially uniform composition. The meteorite is classified as an H4 chondrite.