Sericho Pallasite Meteorite Slice, PMG, 17.39g, Olivine Crystal Mosaic

Olivine crystal density in a compact pallasite slice

This 17.39g slice exposes the classic pallasite architecture: olivine crystals distributed through a continuous iron-nickel matrix in proportions that place Sericho at the high end of olivine content for main group pallasites. The polished face shows crystal clusters separated by metal veins, with the olivine occupying an estimated 70 to 80% of the total volume. Individual crystals range from several millimeters to just over one centimeter across, well-rounded to sub-angular in form.

The olivine has terrestrialized during surface exposure in Kenya, shifting from green toward amber, brown, and deep black. Metal zones between crystal clusters display the brushed metallic luster characteristic of the kamacite-taenite alloy. Both faces carry a thin epoxy coating applied to stabilize the olivine and slow oxidation.

Structure and features

Crystal morphology in this slice reflects the pallasite formation environment: olivine grains suspended in liquid metal at the boundary between a differentiated asteroid's core and mantle. The rounded edges of larger crystals suggest partial resorption in the melt phase before final solidification. Metal-olivine contacts are clean and sharply defined where the polish exposes them.

Terrestrialization progresses from the crystal edges inward, visible as color gradients within individual grains. Some crystals retain translucent amber cores under direct light, surrounded by darker oxidized rims. The metal matrix shows no visible corrosion under the epoxy layer.

Scientific context

Main group pallasites represent samples from the core-mantle boundary of a disrupted asteroid, formed when olivine-rich mantle material mixed with liquid metal from the core during differentiation. Geochemical analysis links PMG pallasites to the IIIAB iron group, suggesting a common parent body. Pallasites account for less than 0.2% of all classified meteorites. Sericho was recovered from a strewn field extending over 45 kilometers in Isiolo County, Kenya, with formal recognition following in 2016. Learn About Meteorites

Frequently asked questions

Is this meteorite authenticated? Sericho is classified in the Meteoritical Bulletin as a main group pallasite. You can verify the classification here: Meteoritical Bulletin search for Sericho. This specimen includes a certificate of authenticity.

What does PMG mean? PMG stands for pallasite main group, the largest subset of pallasites linked by oxygen isotope ratios and trace element chemistry to a single parent body. Main group pallasites are geochemically distinct from the smaller Eagle Station and pyroxene pallasite subgroups.

What is included with this specimen? This listing includes the 17.39g slice and a certificate of authenticity. No display stand is included.

Why is the olivine brown instead of green? Terrestrialization: oxidation of olivine during surface exposure in Earth's atmosphere. This is a natural process in all recovered pallasites and does not affect scientific value or structural integrity under the protective epoxy coating.

Can this slice be backlit? Olivine in Sericho is typically too oxidized for effective backlighting. The terrestrialized crystals appear opaque to dark brown under transmitted light. Metal content also blocks light transmission. This slice exhibits some translucence and is suitable for a backlighting display.

Collector significance

Pallasites remain the most visually distinctive meteorite type collectors can acquire, and Sericho offers accessibility to this category due to the large recovered mass and extended strewn field. This 17.39g slice balances size and price point while retaining the diagnostic olivine-metal texture. The high olivine fraction makes Sericho slices denser in crystal coverage than many other pallasites.

Compact slices like this one serve well in organized collections where space constraints matter. The epoxy coating ensures stability over time, addressing the primary long-term preservation concern with pallasite specimens. Browse additional pallasite specimens: Stony-Iron Meteorites.

Meteoritical Bulletin entry: Sericho | Classification: Pallasite, PMG | Find, Kenya, 2016