Sericho Pallasite Meteorite Full Slice, 103.50g, Polished and Etched

A complete cross section through a Kenyan pallasite, cut from a single stone and finished on both faces. This 103.50 g full slice carries olivine grains distributed through an iron-nickel matrix that has been polished, etched, and sealed with an epoxy coating. The slice is uninterrupted from edge to edge, so the metal and silicate relationship can be read across the whole width of the stone rather than in a fragment of it.

Sericho was recovered from a strewnfield in Isiolo County, Kenya, and classified as a pallasite by L. Garvie, A. Wittmann, and D. Schrader at Arizona State University. The Meteoritical Bulletin records the find year as 2016 and lists the classification in Bulletin 106. As of September 2026, the Meteoritical Bulletin lists this as 1 of 99 approved meteorites classified as Pallasite.

Structure and features

The Bulletin describes Sericho slices as averaging near 70 areal percent olivine, with grains typically 0.5 to 1 cm across and a small number reaching up to 4 cm. Grains are largely rounded and less commonly euhedral, and the published description records them as gemmy green to orange. Both colors are present on this slice, and the transmitted light photograph shows how far light travels through the thinner grains.

The metal is dominated by swathing kamacite around the olivine, with pockets of dark-etching plessite. Etching brings out that structure as tonal contrast across the matrix rather than as a single uniform figure. The Bulletin notes that a well developed Widmanstatten pattern appears only in the occasional metal-rich region of Sericho, so this is a slice to read for its metal and silicate architecture rather than for a classic crossed-band figure.

Accessory troilite and schreibersite are recorded in the classification, along with under 1 areal percent chromite. Weathering grade is stated as low, which is consistent with the surface recoveries described in the Bulletin writeup.

Discovery and provenance

The published history records that in 2016 two brothers searching for their camels came across several large dense stones west of Habaswein and south of Sericho. There are no rocks in that area, so they concluded the masses were meteorites and spent several weeks recovering them with engine hoists. The stones had been known to camel herders for decades before that. One village elder recalled playing on top of them as a child.

In early January 2017 Michael Farmer received a photograph of a 107 kg pallasite, traveled to Nairobi, and purchased the stone. He returned two weeks later with Moritz Karl and was shown more than a ton of material stacked in two house compounds. The Bulletin records more than 2,800 kg found to date across a strewnfield over 45 km long, with individual masses ranging from under 1 kg to 500 kg. The type specimen of 48 g is held at Arizona State University, and the main mass is recorded with Michael Farmer, Moritz Karl, and Thomas Strope.

This specimen was acquired by Treasure Coast Meteorite Co. and prepared in house.

Scientific context

Pallasites pair olivine, a mantle silicate, with iron-nickel metal of the kind found in asteroid cores. Explaining how the two came to sit together in one rock is the central question the class poses, and the leading models involve mixing at a core and mantle boundary or the injection of molten metal into olivine during a large impact. Either way, a pallasite slice shows two parts of a differentiated asteroid that ordinarily never touch.

The olivine composition for Sericho is published as Fa12.3 plus or minus 0.1, with kamacite at 7.1 plus or minus 0.6 weight percent nickel. Those are measured values from the classification work, not estimates from appearance, and they are what distinguishes one pallasite from another once the stones are cut.

Background on the class is set out in what is a pallasite, and the etched metal structure is covered in the Widmanstatten pattern explained.

Frequently asked questions

Is this a full slice or a part slice?
A full slice. The cut runs the complete width of the stone, so the natural exterior margin is present all the way around the specimen rather than on one side only.

What is the coating, and does it affect the stated weight?
The finished faces are sealed with a clear epoxy coating. Pallasites contain iron-nickel metal, which corrodes in humid air if left bare, and the olivine grains sit in that metal, so a sealed surface protects both. The stated 103.50 g is the weight of the specimen as offered, coating included. Epoxy is a permanent treatment and is not intended to be removed.

Will I see a Widmanstatten pattern?
Not as a bold crossed-band figure across the whole face. The Meteoritical Bulletin records that a well developed Widmanstatten pattern appears only in the occasional metal-rich region of Sericho. What the etch shows here is the swathing kamacite around the olivine grains and the darker plessite pockets between them.

Why is a total known weight of 2.8 tonnes quoted for a meteorite sold in gram sizes?
That figure is the recorded mass for the entire Sericho strewnfield, which extends more than 45 km and has produced many separate stones. It describes the find as a whole and says nothing about the size of any one specimen.

How do I verify the classification?
The entry is public. See the Meteoritical Bulletin Database entry for Sericho, and understanding the Meteoritical Bulletin for how to read it. Treasure Coast Meteorite Co. is an IMCA member, number 3323.

Collector significance

Pallasite is a small class. As of September 2026 the Meteoritical Bulletin lists 99 approved pallasites out of more than 80,000 approved meteorites. Sericho is one of the few that has been recovered in enough quantity, and in good enough condition, to be cut into display slices at all, which is why it has become the pallasite most collectors meet first.

A full slice at 103.50 g sits above the small end of that market. The complete cross section, both finished faces, and the intact natural margin make it a specimen that can be handled and displayed from either side. Other stony-iron material is listed in the stony-iron meteorite collection, and general background is indexed on the learn hub.

Classification data on this page is reproduced from the Meteoritical Bulletin Database entry for Sericho, published in Meteoritical Bulletin 106.