English: Irgizites from the Pleistocene of Kazakhstan. (specimen at bottom is ~14 millimeters across at its widest)

Large and small impacts have affected Earth since its formation 4.55 billion years ago. Compared with the intensely pitted and cratered Moon, Earth has relatively few preserved impact craters, because most have been destroyed by water erosion, glacial erosion, and plate tectonic processes. Impact events are accompanied by intense heat, which results in melting of much of the ejected pulverized bedrock. The melted material cools quickly and falls back to Earth in the form of tektites - impact splash glasses. Tektites are principally composed of amorphous silica (SiO2). Broken surfaces show a conchoidal fracture. Tektites from different impact events are given different names.

Irgizites are tektites associated with the Zhamanshin Impact Structure of Kazakhstan. The impact occurred during the Pleistocene - apparently between ~750,000 years to ~1.07 million years ago. Irgizites consist of black glass of varying silica content (~55 to ~79% SiO2). The morphology of irgizites varies - they generally have aerodynamic shapes, many of which have a complex droplet aggregate form.

Locality: unrecorded/undisclosed site near the Zhamanshin Impact Structure, west-central Kazakhstan

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Some info. from:

Kapustkina (1991) - Some peculiarities of the irgizites construction and composition. Abstracts of the Lunar and Planetary Science Conference 22: 679-680.

Gottwald et al. (2020) - Zhamanshin, Kazakhstan. pp. 362-364 in: Terrestrial Impact Structures, The TanDEM-X Atlas 2, Asia, Australia, Europe. Verlag Dr. Friedrich Pfeil. Munich. pp. 309-608.

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See info. at: en.wikipedia.org/wiki/Zhamanshin_crater and

en.wikipedia.org/wiki/Tektite