Trinitite
Trinitite, also known as atomsite or Alamogordo glass, 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 with small amount of calcite, hornblende and augite in a matrix of sandy clay) that was melted by the atomic blast. It was first academically described in "American Mineralogist" in 1948. It is usually a light green, although red trinitite was also found in one  section of the blast site, and rare pieces of black trinitite also formed. It is mildly radioactive but safe to handle. Pieces of the material may still be found at the Trinity site as of 2018, although most of it was bulldozed and buried by the United States Atomic Energy Commission in 1953. Formation. In 2005 it was theorized by Los Alamos National Laboratory scientist Robert Hermes and independent investigator William Strickfaden that much of the mineral was formed by sand which was drawn up inside the fireball itself and then rained down in a liquid form. In a 2010  article in "Geology Today", Nelson Eby of University of Massachusetts at Lowell and Robert Hermes described trinitite: This evidence has been supported by F. Belloni "et al." in a 2011 study based on nuclear imaging and spectrometric techniques. Green trinitite is theorised by researchers to contain material from the bomb's support structure, while red trinitite contains material originating from copper electrical wiring. An estimated 4.3 × 10 ergs or 4.3 × 10 joules of heat energy went into forming the glass and as the temperature required to melt the sand into the glass form observed was about 1470 Celsius , this was the estimated minimum temperature the sand was exposed to. Material within the blast fireball was superheated for an estimated 2–3 seconds before resolidification. Relatively volatile elements such as zinc are found in decreasing quantities the closer the trinitite formed to the centre of the blast; the higher the temperature, the more these evaporated and were not captured as the material resolidified. The detonation left large quantities of trinitite scattered around the crater, with "Time" writing in September 1945 that the site took the appearance of "[a] lake of green jade," while "[t]he glass takes strange shapes—lopsided marbles , knobbly sheets a quarter-inch thick, broken, thin-walled bubbles, green, wormlike forms." The presence of rounded, beadlike forms suggests some material melted after being thrown into the air before landing already formed rather than remaining at ground level and being melted there. Other trinitite formed on the ground, and contains inclusions of infused sand. This trinitite cooled rapidly on its upper surface, while the lower surface was superheated. Composition. The chaotic nature of trinitite's creation has resulted in variations in both structure and precise composition. The glass has been described as "a layer 1 to 2 centimeters thick , with the upper surface marked by a very thin sprinkling of dust which fell upon it while it was still molten. At the bottom is a thicker film of partially fused material, which grades into the soil from which it was derived. The color of the glass is a pale bottle green, and the material is extremely vesicular with the size of the bubbles ranging to nearly the full thickness of the specimen." The most common form of trinitite is green fragments of 1-3cm thick, smooth on one side and rough on the other; this is the trinitite  that cooled after landing still-molten on the desert floor. Around 30% of trinitite is void space, although precise quantities vary greatly between samples. Trinitite also exhibits various other defects such as cracks. In trinitite that cooled after landing, the smooth upper surface contains large numbers of small vesicles while the lower rough layer has lower vesicle density but larger vesicles. It is primarily alkaline. One of the more unusual isotopes found in trinitite is a barium neutron activation product, the barium in the Trinity device coming from the slow explosive lens employed in the device, known as Baratol. Quartz  is the only surviving mineral in most trinitite. Trinitite no longer contains sufficient radiation to be harmful unless swallowed. It still contains the radionuclides Am, Cs and Eu owing to the Trinity test using a plutonium bomb. Variations. There are two forms of trinitite glass with differing refraction indexes. The lower-index glass is composed largely of silicon dioxide, with the higher-index variant having mixed components. Red trinitite exists in both variants, and additionally contains glass rich in copper, iron, and lead as well as metallic globules. Black trinitite's colour is as a result of being rich in  iron. In a study published in 2021 a sample of red trinitite was found to contain a previously undiscovered complex quasicrystal, the oldest known manmade quasicrystal, with a symmetry group in the shape of an icosahedron. It is composed of iron, silicon, copper and calcium. The quasicrystal's structure displays fivefold rotational symmetry, which cannot form naturally. The quasicrystal research was led by geologist Luca Bindi of the University of Florence and Paul Steinhardt, after he theorised red trinitite was likely to contain quasicrystals as they often contain elements that rarely combine. The structure has a formula of . A  single 10μm grain was detected after ten months of work examining six small samples of red trinitite. Nuclear forensics. A 2010 study in the open access journal "Proceedings of the National Academy of Sciences" examined trinitite's potential value to the field of nuclear forensics. Prior to this research, it was assumed trinitite's components fused identically and their original composition could not be discerned. The study demonstrated that glass from nuclear detonations could provide information about the device and associated components, such as packaging. During the 2010s millions of dollars of research was undertaken examining trinitite to better understand  what information such glasses held that could be used to understand the nuclear explosion that created them. The 2010 trinitite analysis was theorized by the team behind it to be useful for identifying perpetrators of a future nuclear attack. Researchers involved with the discovery of the quasicrystal speculated their work could improve efforts to investigate nuclear weapons proliferation since quasicrystals do not decay, unlike other evidence produced by nuclear weapons testing. Trinitite has been chosen as a research subject in part due to how well-documented the nuclear test was by scientists at the time. A 2015 study in "The  Journal of Radioanalytical and Nuclear Chemistry" funded by the National Nuclear Security Administration described a method by which trinitite-like glass could be deliberately synthesized for use as test subjects for new nuclear forensic techniques. Laser ablation was first successfully used to identify the isotopic signature unique to the uranium within the bomb from a sample of trinitite, demonstrating this faster method's effectiveness. Cultural impact. Trinitite was not initially considered remarkable in the context of the nuclear test and ongoing war, but when the war ended visitors began to notice the glass and collect it as souvenirs. For a  time it was believed that the desert sand had simply melted from the direct radiant thermal energy of the fireball and was not particularly dangerous. Thus, it was marketed as suitable for use in jewelry in 1945 and 1946. It is now illegal to take the remaining material from the site, much of which has been removed by the US government and buried elsewhere in New Mexico; however, material that was taken prior to this prohibition is still in the hands of collectors and available legally in mineral shops. Counterfeit trinitite is also on the market; trinitite's authenticity requires  scientific analysis to ascertain. There are samples in the Smithsonian National Museum of Natural History, the New Mexico Farm and Ranch Heritage Museum, and the Corning Museum of Glass; the National Atomic Testing Museum houses a paperweight containing trinitite. Overseas, the UK Science Museum Group collection contains a trinitite sample, as does the Canadian War Museum. The SETI Institute, which seeks to find and research signs of intelligent life elsewhere in space, stated in 2021 that trinitite was to be included in their library of objects connected to "transformational moments" of potential interest to intelligent extraterrestrials. The sculpture "Trinity Cube  by Trevor Paglen, exhibited in 2019 at the Museum of Contemporary Art San Diego as part of a themed collection of Paglen's art titled Sights Unseen, is partially made from trinitite. The c.1988 artwork Trinitite, Ground Zero, Trinity Site, New Mexico" by photographer Patrick Nagatani is housed at the Denver Art Museum. Similar materials. Occasionally, the name "trinitite" is broadly applied to all glassy residues of nuclear bomb testing, not just the Trinity test. Black vitreous fragments of fused sand that had been solidified by the heat of a nuclear explosion were created by French testing at the Reggane  site in Algeria. Following the atomic bombing of Hiroshima, it was discovered in 2016 that between 0.6% and 2.5% of sand on local beaches was fused glass spheres formed during the bombing. Like trinitite, the glass contains material from the local environment, including materials from buildings destroyed in the attack. The material has been called "hiroshimaite". Kharitonchiki (singular: kharitonchik, ) is an analog of trinitite found in Semipalatinsk Test Site in Kazakhstan at ground zeroes of Soviet atmospheric nuclear tests. They are pieces of molten rock left at ground zeroes after Soviet atmospheric nuclear tests. The porous black material is named  after one of the leading Russian nuclear weapons scientists, Yulii Borisovich Khariton. Similar naturally occurring minerals. Trinitite, in common with several similar naturally occurring minerals, is a melt glass. While trinitite and similar materials are anthropogenic, fulgurites, found in many thunderstorm-prone regions and in deserts, are naturally-formed, glassy materials, and are generated by lightning striking sediments such as sand. Impactite, a material similar to trinitite, can be formed by meteor impacts. The Moon's geology includes many rocks formed by one or more large impacts in which increasingly volatile elements are found in lower amounts the closer they  are to the point of impact, similar to the distribution of volatile elements in trinitite.