Sample No: LEW88631

Location: Lewis Cliff

Field Number: 6142

Dimensions (cm): 0.8 x 0.9 x 1.1

Weight (g): 3.2

Meteorite Type: An anomalous iron similar to Horse Creek

Macroscopic Description: Roy S. Clarke. Jr.

This irregularly shaped and somewhat rounded metallic lump is covered with a reddish brown weathering crust. Black, patchy areas within this crust suggest the possibility that weathered fusion crust is present.

Polished Section (,1): Roy S. Clarke. Jr,

A median slice of 370 mg (0.8 x 1.0 cm) was removed for section preparation, leaving butts of 1.11 g and 1.45 g. The sawn surface revealed metal containing a large schreibersite (3.0 x 3.7 mm). Terrestrial corrosion products adhere to edges of the section, and corrosion invades the interior along a series of off-set cracks that penetrate from the edge to the center. Within the corrosion products along exterior edges there are several areas of remnant fusion crust, including one place where both oxidic and melt crust are present. Ablation heating has also melted small areas at the edge of the large schreibersite. A thin rim of α2 structure is present along parts of the exterior metal edge, but most of the metal is kamacite that has not been obviously heat altered. The kamacite contains abundant rhabdites and occasional shock induced distortions. Superimposed upon this basic structure is a dense pattern of fine needles of a silicide mineral, probably perryite. Preliminary electron microprobe analysis of the Si-containing kamacite matrix gave 3.5-4.0 wt% Ni, approximately 0.4 wt% Co, and <0.05 wt% P. The silicide crystals are too thin for easy analysis, but they contain high Ni, with one analysis giving 31 wt% Ni. Silicide crystals also contain small amounts of P. This is an anomalous iron similar to Horse Creek.