Name: Meteorite Hills 00428 This is an OFFICIAL meteorite name. Abbreviation: MET 00428 Observed fall: No Year found: 2000 Country: Antarctica [Collected by US Antarctic Search for Meteorites program (ANSMET)] Mass: 45.8 g
Macroscopic Description: Kathleen McBride and Tim McCoy This 45.8 g ellipsoidal specimen has a frothy exterior. One end of the specimen exhibits a rounded depression. The end of the mass appears as if it may have been torn from another piece during atmospheric passage.
Microscopic Description: Tim McCoy The section is dominated by Fe, Ni metal with 10-20 vol.% of rounded, elongate and ellipsoidal troilite inclusions that range in size from 200 microns to 2 mm in maximum dimension, with most less than 1 mm. The section is bounded by an a2 structure produced during atmospheric heating that extends up to 2 mm into the interior of the meteorite. Rare fusion crust is present. The frothy exterior resulted from a combination of atmospheric ablation and terrestrial weathering of the troilite inclusions. The troilite inclusions exhibit multiple twinning from deformation. No silicate or chromite inclusions were observed. Swathing kamacite surrounds the troilite inclusions. In areas of relatively few troilite inclusions, a weak Widmanstatten pattern is observed, with very thin kamacite lamellae (100-120 microns wide). Kamacite exhibits numerous Neumann bands and these bands are subsequently bent or, in many cases, sheared by subsequent microfaults. Large areas between kamacite bands are dominated by net or finger plessite. The classification of this meteorite is uncertain. Most other troilite-rich meteorites (e.g., Mundrabilla, LEW 86211, Soroti) differ significantly. The closest relative may be the fine octahedrite Mont Dieu, which is a member of group IIE.