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Trinitite, also known as atomsite or Alamogordo glass, [1] [2] is the glassy residue left on the desert floor after the plutonium-based Trinity nuclear bomb test on July 16, 1945, near Alamogordo, New Mexico. The glass is primarily composed of arkosic sand composed of quartz grains and feldspar (both microcline and smaller amount of plagioclase ...
Libyan desert glass or Great Sand Sea glass is an impactite, made mostly of lechatelierite, [1] found in areas in the eastern Sahara, in the deserts of eastern Libya and western Egypt. Fragments of desert glass can be found over areas of tens of square kilometers. Like obsidian, it was knapped and used to make tools during the Pleistocene. [2]
The glass transition temperature of basalt is about 700 °C (1,292 °F). [4] The mechanisms controlling formation of volcanic glass are further illustrated by the two forms of basaltic glass, tachylite and sideromelane. Tachylite is opaque to transmitted light because of the abundance of tiny oxide mineral crystals suspended in the glass ...
Minerals such as cubanite, troilite and calcium-aluminum-rich inclusions found in the glass were also found in debris from a comet that was collected during NASA's Stardust mission, according to ...
Quartzite can have a grainy, glassy, sandpaper-like surface 'Quartzite is a hard, non-foliated metamorphic rock which was originally pure quartz sandstone. [1] [2] Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts.
Such current may propagate into silica-rich quartzose sand, mixed soil, clay, or other sediments, rapidly vaporizing and melting resistant materials within such a common dissipation regime. [3] This results in the formation of generally hollow and/or vesicular, branching assemblages of glassy tubes, crusts, and clumped masses. [4]
Aphanitic (a = not, phaner = visible) rocks, in contrast to phaneritic rocks, typically form from lava which crystallize rapidly on or near Earth's surface. When extrusive rocks make contact with the atmosphere they cool quickly, so the minerals do not have time to form large crystals. The individual crystals in an aphanitic igneous rock are ...
It is generally glassy or fine-grained in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral assemblage is predominantly quartz, sanidine, and plagioclase. It is the extrusive equivalent of granite.