Impact Glass – Impactite; Zhamanshin Crater, Kazakstan (48° 24′ 0″ N, 60° 58′ 0″ E)

Impactites are terrestrial rocks that have been impacted by asteroids or comets. Following such a meeting of worlds, terrestrial rock is shocked, shattered and melted. At times, as a result of such extremely high-pressure events, new minerals including microdiamonds form. Impactite may be found on or beneath the floor of the impact crater, in the rim, or as ejecta (material launched from the crater following the collision). As might be imagined, impact craters are identified by the very presence of impactite, as well as other signature impact products such as shatter cones and impact glass (see lot 66).

The impact at Zhamanshin occurred in the Pleistocene approximately 900,000 years ago; the crater measures 14 kilometers (6.33 miles) in diameter. The Zhamanshin event was the most recent impact of sufficient magnitude to create a climate shift akin to a nuclear winter — but insufficiently energetic to have caused a mass extinction. While there are different impact products found in proximity to Zhamanshin Crater — including pure glass — now offered is a fragment of impact-melt rock that contains natural glass as a result of the extraordinary heat generated by the impact. Due to its high silica content, there is a gleaming vitreous quality to the specimen and vesicles are abundant. While the swirling rippled material which ranges in hues from tan to taupe may evoke a variety of desserts, it is the product of a devastating asteroid impact on Earth.

Christie's would like to thank Dr. Alan E. Rubin at the Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles for his assistance in preparing this catalogue.

113 x 168 x 146mm (4.5 x 6.66 x 5.75 in.) and 1778.8g (4 lbs)