Seymchan Pallasite Full Slice, PMG, 286.28g, Translucent Olivine

About this specimen

This is a 286.28 g full slice of Seymchan, a pallasite from the Magadan region of Russia. The Meteoritical Bulletin Database records the recommended classification as Pallasite, PMG, the find year as 1967, and the country as Russia. It is recorded as a find rather than an observed fall.

The meteorite spent four decades on the books as an iron. It was reclassified in 2007 after olivine bearing material turned up at the same locality, and the cut face on this slice is the material that forced the change.

Structure and features

Olivine covers the face densely and reaches the margins on every side, so there is no quiet zone of bare metal at the edges. Under transmitted light the crystal field lights up across the whole width of the slice, from pale straw and lemon through honey into deep orange and occasional near red, with a scatter of darker crystals holding the pattern together.

Transmission is the variable that separates one pallasite slice from another. Olivine in pallasites is often clouded, fractured or simply opaque, and how much of it passes light differs from mass to mass and from cut to cut within a single mass. On this slice the light passing fraction is high enough that the specimen changes character completely depending on whether it is lit from in front or behind. The photographs above show it both ways so the difference can be judged before buying rather than after.

Crystal outlines are angular and the individual crystals here run smaller and more numerous than on a coarse pallasite cut, which is what produces the dense scatter across the face. Metal separates the clusters as veins and pockets rather than as broad open areas.

The metal is mirror polished and has not been acid etched. Etching develops the Widmanstatten pattern in the metal at the cost of leaving the surface matte and grey. A mirror finish keeps the matrix bright, which is what a face carrying this much olivine wants behind and between the crystals. Anyone after the etched structure should be looking at an iron rather than at this slice.

Both faces carry a light epoxy coating applied as a moisture barrier. It is thin, it does not obscure the olivine or dull the metal, and it is ordinary practice for iron bearing meteorites meant for open display. Handling and storage guidance is set out in how to care for and store a meteorite, and the underlying issue is covered in do meteorites rust.

Discovery and provenance

The Meteoritical Bulletin writeup, published as Meteoritical Bulletin no. 43 in Moscow in 1968 and reprinted in Meteoritics 5, 85 to 109 in 1970, records the circumstances. The meteorite was found in a brook bed flowing into the river Hekandue, a left tributary of the river Jasachnaja, in the Magadan district. Two individual specimens were recovered. The larger was found in June 1967 by the geologist F. A. Mednikov during a geological survey, lying among the stones of the brook bed. The smaller was found at a distance of 20 m from the first by I. H. Markov with a mine detector in October 1967. The writeup records that the main mass was turned over to the Academy of Sciences of the USSR.

Recorded coordinates are 62 degrees 54 minutes N, 152 degrees 26 minutes E. Seymchan is one of 6 approved meteorites from Magadanskaya oblast, Russia.

This specimen was acquired by Treasure Coast Meteorite Co. and prepared as a full slice, mirror polished on both faces and given a light epoxy coating as a moisture barrier. It carries serial TC-00041 and a permanent specimen record page.

Scientific context

The classification history in the Bulletin database runs as a sequence of corrections. Meteoritical Bulletin 43 in 1968 recorded Seymchan as Iron. The NHM Catalogue 5th Edition in 2000 recorded it as IIE. MetBase version 7.1 in 2006 recorded it as Iron ungrouped. The recommended classification today is Pallasite, PMG. The database comments field records the reclassification against van Niekerk et al. (2007), with a revision dated 26 May 2009 covering revised pallasite classifications.

The 2007 abstract behind the change, Seymchan: A Main Group Pallasite, Not an Iron Meteorite, presented at the 70th Annual Meteoritical Society Meeting, sets out the evidence. A 2004 expedition to the locality recovered further masses, and the abstract notes reports that roughly 20 percent of those newer finds were pallasitic or partly pallasitic while the remainder were iron. Oxygen isotope analysis of the silicate placed it inside the main group pallasite field, and the metal composition matched the original iron masses. The meteorite had always been heterogeneous. The first people to study it simply had metal in front of them.

Pallasites have long been read as material from the boundary region between the metallic core and the silicate mantle of a differentiated asteroid, though the setting in which they formed remains under active debate. Background on the class is set out in what is a pallasite, and the way classifications are assigned and revised is covered in how are meteorites classified.

Seymchan is one of 79 approved meteorites classified as Pallasite, PMG, as recorded in the Meteoritical Bulletin Database in September 2026.

Frequently asked questions

Why was Seymchan reclassified from an iron to a pallasite?
The two masses recovered in 1967 were metal, and the meteorite was described from them. A 2004 expedition to the same locality recovered further masses, some carrying olivine. Oxygen isotope work on that silicate placed it in the main group pallasite field while the metal chemistry matched the original irons, which established that one heterogeneous meteorite was involved rather than two separate ones. The Bulletin database records the reclassification against van Niekerk et al. (2007).

How much of the olivine actually passes light?
A large share of it, across the full width of the face. The backlit photographs above are of this specific slice and are not stock images. Some crystals stay dark and the darker ones do not transmit at all, which is normal for the material and visible in the images.

Does this slice show a Widmanstatten pattern?
No. The faces are mirror polished rather than acid etched, so the metal reads as a bright reflective matrix instead of a patterned one. This is a preparation decision rather than an omission. Etching would develop the pattern but would leave a matte grey surround for the olivine, which is the wrong trade on a slice whose value is in the transparency of its crystals.

What is the epoxy coating for?
It is a thin moisture barrier. Iron bearing meteorites take up atmospheric moisture and can corrode over time without protection. The coating is light enough that it does not change the appearance of the olivine or the metal, and it is disclosed here rather than left to be found later.

Was Seymchan seen to fall?
No. The Bulletin database records it as a find, with a find year of 1967.

What documentation comes with it?
A certificate card bearing serial TC-00041, and a permanent specimen record page on this site giving the identification and classification data, the recorded weight, and photographs of this specimen. The serial is an index to that record.

Collector significance

Seymchan is available material and small slices of it are not difficult to find. Large slices carrying a high proportion of light passing olivine are a much narrower proposition, because olivine content varies across the meteorite and the transparency of that olivine varies again on top of it. At 286.28 g this sits well above the size at which pallasite material is usually offered, and the backlit face is the reason to want it rather than a bonus feature of it.

It is also a full slice. Most pallasite on the market is part slice material cut from the interior of a mass, which shows the olivine but not the shape of the stone that carried it. A complete cross section keeps the natural margin the whole way around and reads as a section through a specific object rather than a sample taken from one. Full slices at this weight are a far smaller pool than part slices at the same weight, and they are not directly comparable on price per gram.

The meteorite also carries an unusually legible piece of scientific history. Reclassifications of this kind are infrequent, and this one is documented, dated and citable rather than anecdotal. The path from Iron in 1968 to Pallasite, PMG today can be followed through the database record itself.

Offered by Treasure Coast Meteorite Co., IMCA Member #3323, Hobe Sound, Florida. Further pallasite and iron material is listed in the stony iron meteorite collection. Classification data on this page is reproduced from the Meteoritical Bulletin Database entry for Seymchan, maintained by the Nomenclature Committee of the Meteoritical Society and hosted by the Lunar and Planetary Institute. How that database works and what its entries record is explained in understanding the Meteoritical Bulletin.