Sample No.: LEW88023

Location: Lewis Cliff

Dimensions (cm): 2x1.5x0.4

Field Number: None

Weight (g): 8.0

Meteorite Type: Reheated octahedrite (?) with trace silicates

Macroscopic Description: Roy S. Clarke, Jr.

This specimen was not thought to be a meteorite in the field and was identified later by Randy Korotev at Washington University. Reddish-brown terrestrial oxides cover its surfaces. It is a flat oval with rounded edges, having one domed surface and a flat surface, suggesting a posterior and an anterior surfaces during oriented atmospheric flight.

Polished Section Description; Roy S. Clarke, Jr.

A thin slice was removed from one end of the specimen, perpendicular to its long axis, providing an area of approximately 0.5 cm² for examination. The surface is mainly recrystallized kamacite containing 6.5% Ni, unusually low levels of P, and bordered by terrestrial oxides varying in width from 0.05 to 0.5 mm. The size of recrystallized kamacite areas are much smaller along the domed surface edge and at the ends of the slice, suggesting a heat-altered zone associated with an anterior surface. Interior recrystallization may have occurred prior to atmospheric passage. Very small amounts of heat-altered taenite are present, but insufficient surface area is available to establish the scale should a coarse Widmanstätten pattern have existed. The kamacite contains tiny precipitates, particularly decorating subboundaries, that are too small to be identified. No clearly recognizable schreibersite was seen. Two areas containing chains of silicate inclusions were observed. Individual silicates are a few microns on an edge, with a total area of about 0.02 mm². Pyroxene, olivine, and plagioclase were identified, as was an associated chromite of about 0.005 mm². In surface repolishing the chromite was lost, but troilite was revealed as also being part of the association.