SEYMCHAN PALLASITE - 30MM X 20MM - 26.5CT
First discovered during the summer of 1967 by the Russian geologist F. A. Mednikov, Seymchan was originally classified as an IIE iron meteorite. In the early 2000s, meteorite hunters associated with the Vernadsky Institute in Moscow returned to the site in the hope of finding additional specimens. They did. And there were amazed to discover not iron meteorites, but pallasites — stony-iron meteorites encrusted with olivine crystals. Their finds resulted in a rare classification change in the scientific literature: in 2007 van Niekerk et al. revised the designation for Seymchan from iron to pallasite.
Pallasites contain big, beautiful olive-green crystals - a form of magnesium-iron silicate called olivine - embedded entirely in metal. Sometimes the olivine does not occur as a single crystal but as a cluster. Elsewhere it can create a pattern of veins through solid metal. The scientific jury is still out on exactly how pallasite meteorites formed. Some scientists believe they formed in melted asteroids in a similar way to iron meteorites, where dense iron metal sinks toward the center to form an iron core.
Pallasites are thought to be samples of the boundaries between a metal core and the silicate, olivine-rich mantle around it. If this is the case, they could tell us a lot about the formation of Earth and other terrestrial planets. However, other scientists think that there are very few olivine-rich meteorites in the asteroid belt, and too many pallasite meteorites for them all to have come from a core-mantle boundary.
The crystals seen here are the result of small chunks of the stony mantle becoming suspended in the molten metal of an asteroid’s iron-nickel core. Cut and polished, the lustrous metallic matrix features silicate crystals of gleaming olivine and peridot (gem-quality olivine) ranging in hues from emerald to amber.