First discovered during the summer of 1967 by the Russian geologist F.A. Mednikov, Seymchan has an unusual structure; some areas display olivine-rich clusters, while others consist almost entirely of nickel-iron. During its tumultuous flight through the atmosphere and subsequent impact, it is easy to imagine the meteoritic masses of Seymchan shearing at the nickel-iron/olivine borders. Some pieces, therefore, appear to be entirely metallic, while others appear pallasitic. This explains why Mednikov found what he assumed to be an entirely iron, or sideritic meteorite, while later expeditions found what they assumed to be pallasites.