Sample No.: ALH82132

Location: Allan Hills

Field No.: 2983

Weight (gms): 5.9

Meteorite Type: E4 Chondrite

Physical Description: Roberta Score

Some fusion crust remains on this otherwise iridescent reddish-brown, highly oxidized stone. Thin evaporite deposit coats some of the extensively weathered interior surfaces. Dimensions: 2 x 2 x 1 cm

Petrographic Description: Brian Mason

Chondrules are relatively abundant, but are small, ranging up to 0.6 mm in diameter; most of them consist of pyroxene, but some are made up entirely or almost entirely of nickel-iron and troilite. The matrix consists largely of granular pyroxene, with lesser amounts of nickel-iron and sulfides, and a little plagioclase and a silica polymorph. The meteorite is considerably weathered, with brown limonitic staining throughout the section. Microprobe analyses show that the pyroxene is almost pure MgSiO3 (FeO 0.06-0.7, mean 0.3%; A12O3 0-0.3, mean 0.04%; CaO 0.02-0.6, mean 0.16%; TiO2, MnO, less than 0.05%). Plagioclase is almost pure albite (CaO 0.02%, K2O 0.11%). The meteorite is an enstatite chondrite, and since part of the pyroxene is polysynthetically twinned clinoenstatite, it is classified as an E4 chondrite.