Iron, coarse octahedrite – IIAB Maritime Territory, Siberia, Russia (46°9' N, 134°39' E)

After having broken off its parent asteroid 320 million years ago, a massive iron mass wandered through interplanetary space until a close encounter with Earth on February 12, 1947. A fireball brighter than the Sun (it created moving shadows in broad daylight) was seen to explode at an altitude of about 6 km over eastern Siberia. Sonic booms were heard at distances up to 300 km from the point of impact. Chimneys collapsed, windows shattered and trees were uprooted. A 33 km-long smoke trail persisted for several hours in the atmosphere after impact. Iron fragments were scattered over a broad elliptical area. Many of the meteorites penetrated the soil, producing impact craters up to 26 meters across; about 200 such depressions have been catalogued. A famous painting of the event by artist and eye-witness P. I. Medvedev was reproduced as a postage stamp issued by the Soviet government in 1957 to commemorate the impact’s 10th anniversary.
As evidenced by the regmaglypts (thumbprints) blanketing one side of this mass, this meteorite was not part of the massive low altitude explosion. Instead, this specimen broke off at a higher altitude, providing sufficient time for frictional superheating with the atmosphere to form the regmaglypts. The groove-like reverse reveals that this meteorite ripped apart yet again at a high-enough altitude that additional shallow regmaglypts were able to form.