Sample No.: ALHA77182

Location: Allan Hills

Field No.: Y78010313A

Weight (gms): 1134.7

Meteorite Type: H5 Chondrite

Physical Description:

No fusion crust is apparent on this angular specimen, 12.5x8.0x7.0 cm. The over all color of the sample is orangish-brown. A band, approximately 1.5 cm wide, o yellowish-green material crosses the meteorite on the E-W axis. It is apparent by looking at the T surface that this is not just a surface feature. Many random fractures cover the surface of the meteorite. Numerous irregular (lithic fragments and chondrules, up to as much as 0.5 cm in diameter, are apparent. This sample appears exfoliated. Surfaces revealed by sawing exhibited metallic particles, approximately 1-2 mm it diameter, in addition to chondrules and lithic fragments. The largest of these inclusions is approximately 0.5 mm in length. Three fractures, 3 cm in length, are apparent in the cut face. The meteorite has no weathering rind and no weathering along fractures.

Petrographic Description: Brian Mason

The thin section shows well-developed chondritic structure, with a variety of chondrule types; chondrule diameters range from 0.5-1.5 mm. The chondrules are set in a granular matrix consisting mainly of olivine and orthopyroxene, with minor amounts of nickel-iron and lesser amounts of troilite; many of the nickel iron grains are partly altered to red-brown limonite. Microprobe analyses show olivine (Fa19) and orthopyroxene (Fs17) of uniform composition; minor plagioclase (An12) was also identified. The meteorite is classed as an H5 chondrite.