National Aeronautics
and Space Administration

Macroscopic Description: Tim McCoy
This small (1.5 x 1.25 x 0.75 mm; 4.85 grams) sample exhibits a bluish-silver exterior reminiscent of both fusion crusted iron (e.g., San Francisco Mts.) and irons which have had the exterior removed as a result of ablation by sand or ice. Numerous large cracks are present and the meteorite has obviously split along one of these fractures, producing a planar boundary which abuts a jagged surface and together which form an indentation into an otherwise rounded specimen.

Thin Section (,2) Description: Tim McCoy
The longitudinal section measures ~7 x 7 mm. One end of the section is rounded and represents the original surface of the meteorite. The opposite end is truncated along a linear edge. The bulk of the meteorite is composed of kamacite with an α2 structure. The section is bounded by a weathered crust that rarely overlies small pockets of fusion crust. Inset from the straight edge of the section and parallel to it at regular spacings of ~2 mm are, first, a taenite lamellae (up to 34 wt.% Ni) ~50 µm in width which contain along its length irregular ~100 µm pockets of taenite and P-rich, Ni-rich melt (28 wt.% Ni, 11 wt.% P) in a eutectic relationship. A further ~2 mm into the meteorite is a fracture, now filled with terrestrial iron hydroxides, that includes larger grains of taenite (up to 23 wt.% Ni). The larger particles, reaching a few hundreds microns, sometimes contain oriented kamacite plates. A representative traverse yields an average composition of 7.2 wt.% Ni, 0.1 wt.% P and 0.6 wt.% Co. The meteorite is an iron and could be related to a number of groups (e.g., IIAB, IIIAB, IAB). The Ni and P concentrations might suggest group IIIAB. It is, however, unlikely that it is representative of the larger mass from which it was derived.

Thin Section Images

Reflected Light MIL 05147

Lab Images