"These sorts of glasses can be made of quite different kinds of materials than silica: metallic alloys, ionic melts, aqueous solutions, molecular liquids, and polymers. For many applications, like glass bottles or eyewear, polymer glasses (acrylic glass, polycarbonate or polyethylene terephthalate) are a lighter alternative than traditional glass. Silicon dioxide (SiO) is a common fundamental constituent of glass. In nature, vitrification of quartz occurs when lightning strikes sand, forming hollow, branching rootlike structures called fulgurites. Fused quartz is a glass made from chemically-pure silica. It has excellent resistance to thermal shock, being able to survive immersion in water while red"
"Tektite Tektites (from Greek τηκτός ""tēktós"", ""molten"") are gravel-sized bodies composed of black, green, brown, or gray natural glass formed from terrestrial debris ejected during meteorite impacts. The term was coined by Austrian geologist Franz Eduard Suess (1867–1941), son of Eduard Suess. They generally range in size from millimeters to centimeters. Millimeter-scale tektites are known as microtektites. Tektites are characterized by: Although tektites are superficially similar to some terrestrial volcanic glasses (obsidians), they have unusual distinctive physical characteristics that distinguish them from such glasses. First, they are completely glassy and lack any microlites or phenocrysts, unlike terrestrial volcanic glasses. Second,"
"tube-like, crust-like, or slag-like objects known as fulgurite (fulgar in Latin means ""lightning""). Just as lightning strikes can branch in various directions - or produce knot-like balled forms - fulgurite forms dendritic or beaded configurations, often following the characteristic shape of plant roots or other organic-filled cavities in the ground. Fulgurite is important in the study of paleoclimate because they are an artifact of past lightning storms. Since fulgurite is of a glass-like structure, those of tube morphology are brittle, and samples can vary in length and thickness, often as a result of their depositional environment. For example, fulgurite found"
"from ""fiery rock dust cloud"" (from the Latin ""igni-"" (fire) and ""imbri-"" (rain)). Ignimbrites form as the result of immense explosions of pyroclastic ash, lapilli and blocks flowing down the sides of volcanoes. Ignimbrites are made of a very poorly sorted mixture of volcanic ash (or tuff when lithified) and pumice lapilli, commonly with scattered lithic fragments. The ash is composed of glass shards and crystal fragments. Ignimbrites may be loose and unconsolidated, or lithified (solidified) rock called lapilli-tuff. Near the volcanic source, ignimbrites commonly contain thick accumulations of lithic blocks, and distally, many show meter-thick accumulations of rounded cobbles"
"Hyaloclastite Hyaloclastite is a volcaniclastic accumulation or breccia consisting of glass (from the Greek ""hyalus"") fragments (clasts) formed by quench fragmentation of lava flow surfaces during submarine extrusion. It occurs as thin margins on the lava flow surfaces and between pillow lavas as well as in thicker deposits, more commonly associated with explosive, volatile-rich eruptions as well as steeper topography. Hyaloclastites form during volcanic eruptions under water, under ice or where subaerial flows reach the sea or other bodies of water. It commonly has the appearance of angular flat fragments sized between a millimeter to few centimeters. The fragmentation occurs"
"can be dissolved by acidic solutions obtained from plants. Research led by Joseph Davidovits of the Geopolymer Institute in France has been offered in support of this hypothesis. However, most of the spheres were created from gabbro, an acid-resistant igneous rock. In the cosmogony of the Bribri, which is shared by the Cabecares and other American ancestral groups, the stone spheres are “Tara’s cannon balls”. Tara or Tlatchque, the god of thunder, used a giant blowpipe to shoot the balls at the Serkes, gods of winds and hurricanes, in order to drive them out of these lands. It has been"
"and is a common component of a type of glassy ejecta called tektites. Most tektites are blobs of impure glassy material, but tektites from the Sahara Desert in Libya and Egypt, known as ""Libyan desert glass"", are composed of almost pure silica that is almost pure lechatelierite. High pressure experiments have shown that shock pressures of 85 GPa are needed to produce lechatelierite in quartz grains embedded in granite. Lechatelierite was formed during the impact of a meteorite into a layer of Coconino Sandstone at Meteor Crater in Arizona. During the rapid pressure reduction following the impact, steam expanded the"
"in general. However, fulgurite, a glassy tube-like, crust-like, or irregular mineraloid that forms when lightning fuses soil, quartz sands, clay, rock, biomass, or caliche is prevalent in electrically-active regions around the globe and provides evidence of not only past lightning activity, but also patterns of convection. Since lightning channels carry an electric current to the ground, lightning can produce magnetic fields as well. While lightning-magnetic anomalies can provide evidence of lightning activity in a region, these anomalies are often problematic for those examining the magnetic record of rock types because they disguise the natural magnetic fields present. The atmospheric composition"
"Helenite Helenite, also known as Mount St. Helens obsidian, emerald obsidianite, and ruby obsidianite, is an artificial glass made from the fused volcanic rock dust from Mount St. Helens and marketed as a gemstone. Helenite was first created accidentally after the eruption of Mount St. Helens in 1980. Workers from the Weyerhaeuser Timber Company were attempting to salvage equipment damaged after the volcanic eruption. Using acetylene torches, they noticed that the intense heat was melting the nearby volcanic ash and rock and turning it a greenish color. The silica, aluminium, iron, and trace amounts of chromium and copper present in"
"newly formed lechatelierite. The shattered and expanded glass has a density less than that of water. Lechatelierite may also form artificially, a unique example being the ""trinitite"" produced by melting of quartz sand at the first nuclear bomb explosion at Trinity Flats, White Sands, New Mexico. Lechatelierite Lechatelierite is silica glass, amorphous SiO, non-crystalline mineraloid. Lechatelierite is a mineraloid as it does not have a crystal structure. Although not a true mineral, it is often classified in the quartz mineral group. One common way in which lechatelierite forms naturally is by very high temperature melting of quartz sand during a"
"Tholin Tholins (after the Greek ("""") ""hazy"" or ""muddy""; from the ancient Greek word meaning ""sepia ink"") is an informal name given to a wide variety of organic compounds formed by solar ultraviolet irradiation or cosmic rays from simple carbon-containing compounds such as carbon dioxide (), methane () or ethane (), often in combination with nitrogen (). Tholins do not form naturally on modern-day Earth, but they are found in great abundance on the surface of icy bodies in the outer Solar System, and as reddish aerosols in the atmosphere of outer Solar System planets and moons. When in the"
"are caused by hot ejecta falling on ground containing ice. The pits are formed by heat forming steam that rushes out from groups of pits simultaneously, thereby blowing away from the pit ejecta. Noctis Labyrinthus is a large canyon system found in the Phoenicis Lacus quadrangle. Its walls contain many layers of rocks. Research, described in December 2009, found a variety of minerals—including clays, sulfates, and hydrated silicas in some of the layers. Lava sometimes forms a tube as it moves away from the vent (opening from which lava flows from a volcano). The top of a stream of lava"
"Agricola, in ""De re metallica"", reported a traditional serendipitous ""discovery"" tale of familiar type: ""The tradition is that a merchant ship laden with nitrum being moored at this place, the merchants were preparing their meal on the beach, and not having stones to prop up their pots, they used lumps of nitrum from the ship, which fused and mixed with the sands of the shore, and there flowed streams of a new translucent liquid, and thus was the origin of glass."" This account is more a reflection of Roman experience of glass production, however, as white silica sand from this"
"vesicular masses, and clusters of refractory materials that often form during the discharge phase of lightning strikes propagating into silica-rich quartzose sand, mixed soil, clay, or other sediments. Fulgurites are homologous to Lichtenberg figures, which are the branching patterns produced on surfaces of insulators during dielectric breakdown by high-voltage discharges, such as lightning. Fulgurites are formed when lightning strikes the ground, fusing and vitrifying mineral grains. Peak temperatures within a lightning channel are known to exceed 30,000 K, with sufficient pressure to produce planar deformation features, or ""shock lamellae,"" in SiO, a kind of polymorphism. This is also known colloquially"
"probably carved by liquid water. Ismenius Lacus is the name of a telescopic albedo feature located at 40° N and 30° E on Mars. The term is Latin for Ismenian Lake, and refers to the Ismenian Spring near Thebes in Greece where Cadmus slew the guardian dragon. Cadmus was the legendary founder of Thebes, and had come to the spring to fetch water. The name was approved by the International Astronomical Union (IAU) in 1958. There appeared to be a large canal in this region called Nilus. Since 1881–1882 it was split into other canals, some were called Nilosyrtis, Protonilus"
"cannot be seen with the naked eye, but they can be seen in images taken from telescopes or orbiting spacecraft. Before the Apollo missions, scientists believed that they were deposits produced by pyroclastic eruptions. Some deposits appear to be associated with dark elongated ash cones, reinforcing the idea of pyroclasts. The existence of pyroclastic eruptions was later confirmed by the discovery of glass spherules similar to those found in pyroclastic eruptions here on Earth. Many of the lunar basalts contain small holes called vesicles, which were formed by gas bubbles exsolving from the magma at the vacuum conditions encountered at"
"Libyan desert glass Libyan Desert glass (LDG), or Great Sand Sea glass is an impactite 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. The origin of desert glass is uncertain. Meteoritic origins have long been considered possible, and recent research links the glass to impact features, such as zircon-breakdown, vaporized quartz and meteoritic metals, and to an impact crater. Some geologists associate the glass with radiative melting from meteoric large aerial bursts, making it analogous to trinitite created"
"Chlorophane Chlorophane, also sometimes known as pyroemerald, cobra stone, and pyrosmaragd, is a rare variety of the mineral fluorite with the unusual combined properties of thermoluminescence, thermophosphoresence, triboluminescence, and fluorescence: it will emit light in the visible spectrum when exposed to ultraviolet light, when heated, and when rubbed; if heated, it will continue to emit light for a period of time after a heat source is withdrawn. The small amount of heat generated by being held in the hand has been reported as enough to induce luminiscence, though this may be the result of experimental error. Although chemically very similar"
"""thunderstone"" has also been traditionally applied to the fossilised rostra of belemnoids. The origin of these bullet-shaped stones was not understood, and thus a mythological explanation of stones created where a lightning struck has arisen. The thunderbolt or lightning bolt continues into the modern world as a prominent symbol; it has entered modern heraldry and military iconography. Thunderbolt A thunderbolt or lightning bolt is a symbolic representation of lightning when accompanied by a loud thunderclap. In Indo-European mythology, the thunderbolt was identified with the 'Sky Father'; this association is also found in later Hellenic representations of Zeus and Vedic descriptions"
"from sand exposed to the thermal radiation of a nuclear explosion. Libyan Desert glass has been dated as having formed about 26 million years ago. It was knapped and used to make tools during the Pleistocene. Libyan desert glass Libyan Desert glass (LDG), or Great Sand Sea glass is an impactite 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. The origin of desert glass is uncertain. Meteoritic origins have long been considered possible, and recent research links the"
"Lechatelierite Lechatelierite is silica glass, amorphous SiO, non-crystalline mineraloid. Lechatelierite is a mineraloid as it does not have a crystal structure. Although not a true mineral, it is often classified in the quartz mineral group. One common way in which lechatelierite forms naturally is by very high temperature melting of quartz sand during a lightning strike. The result is an irregular, branching, often foamy hollow tube of silica glass called a fulgurite. Not all fulgurites are lechatelierite; the original sand must be nearly pure silica. Lechatelierite also forms as the result of high pressure shock metamorphism during meteorite impact cratering"
"the area. Movies filmed at the La Brea Tar Pits include ""Volcano"", ""My Girl 2"", ""Miracle Mile"", ""Last Action Hero"", and ""Seven Psychopaths"". La Brea Tar Pits The La Brea Tar Pits are a group of tar pits around which Hancock Park was formed in urban Los Angeles. Natural asphalt (also called asphaltum, bitumen, pitch or tar—""brea"" in Spanish) has seeped up from the ground in this area for tens of thousands of years. The tar is often covered with dust, leaves, or water. Over many centuries, the tar preserved the bones of trapped animals. The George C. Page Museum"
"Terracotta Terracotta, terra cotta or terra-cotta (; Italian: ""baked earth"", from the Latin ""terra cocta""), a type of earthenware, is a clay-based unglazed or glazed ceramic, where the fired body is porous. Terracotta is the term normally used for sculpture made in earthenware, and also for various utilitarian uses including vessels (notably flower pots), water and waste water pipes, roofing tiles, bricks, and surface embellishment in building construction. The term is also used to refer to the natural brownish orange color of most terracotta, which varies considerably. This article covers the senses of terracotta as a medium in sculpture, as"
"called lenses, such as microwave lenses, electron lenses, acoustic lenses, or explosive lenses. The word ""lens"" comes from "" lēns "", the Latin name of the lentil, because a double-convex lens is lentil-shaped. The lentil plant also gives its name to a geometric figure. Some scholars argue that the archeological evidence indicates that there was widespread use of lenses in antiquity, spanning several millennia. The so-called Nimrud lens is a rock crystal artifact dated to the 7th century BC which may or may not have been used as a magnifying glass, or a burning glass. Others have suggested that certain"
"that of the shock. Thunder without lightning is the result of the wind being too weak to emit any flame, but strong enough to produce a sound. A flash of lightning without thunder is a jolt of the air that disperses and falls, allowing a less active fire to break free. Thunderbolts are the result of a thicker and more violent air flow. He saw the sea as a remnant of the mass of humidity that once surrounded Earth. A part of that mass evaporated under the sun's action, thus causing the winds and even the rotation of the celestial"
"of silica tetrahedra. Pyroxenes that crystallize in the monoclinic system are known as clinopyroxenes and those that cystallize in the orthorhombic system are known as orthopyroxenes. The name pyroxene is derived from the Ancient Greek words for ""fire"" (πυρ) and ""stranger"" (ξένος). Pyroxenes were so named because of their presence in volcanic lavas, where they are sometimes seen as crystals embedded in volcanic glass; it was assumed they were impurities in the glass, hence the name ""fire strangers"". However, they are simply early-forming minerals that crystallized before the lava erupted. The upper mantle of Earth is composed mainly of olivine"
"Thunderegg A thunderegg (or thunder egg) is a nodule-like rock, similar to a filled geode, that is formed within rhyolitic volcanic ash layers. Thundereggs are rough spheres, most about the size of a baseball—though they can range from less than an inch to over a meter across. They usually contain centres of chalcedony which may have been fractured followed by deposition of agate, jasper or opal, either uniquely or in combination. Also frequently encountered are quartz and gypsum crystals, as well as various other mineral growths and inclusions. Thundereggs usually look like ordinary rocks on the outside, but slicing them"
"a dense plume of particles. The ash density and constant motion within the volcanic plume produces charge by frictional interactions (triboelectrification), resulting in very powerful and very frequent flashes as the cloud attempts to neutralize itself. Due to the extensive solid material (ash) content, unlike the water rich charge generating zones of a normal thundercloud, it is often called a dirty thunderstorm. Lightning has been observed within the atmospheres of other planets, such as Jupiter and Saturn. Although in the minority on Earth, superbolts appear to be common on Jupiter. Lightning on Venus has been a controversial subject after decades"
"phenomenon in plasma physics. A free-floating plasma orb, created when surface electricity (e.g., from a capacitor) is discharged into a solution. However, most plasma ball experiments are conducted using high voltage capacitors, microwave oscillators, or microwave ovens, not under natural conditions. Naga fireball Naga fireballs (; ), also known as ""bung fai phaya nak"" or ""Mekong lights"", and formerly, ""ghost lights"" are a phenomenon said to be seen annually on the Mekong River. Glowing balls are alleged to naturally rise from the water high into the air. The balls are said to be reddish and to range in size from"
"Dirty thunderstorm A dirty thunderstorm (also volcanic lightning, thunder volcano) is a weather phenomenon that is related to the production of lightning in a volcanic plume. The earliest recorded observations of a dirty thunderstorm are from Pliny the Younger, describing the eruption of Mount Vesuvius in 79 AD. “There was a most intense darkness rendered more appalling by the fitful gleam of torches at intervals obscured by the transient blaze of lightning.” The first studies of volcanic lightning were also conducted at Mount Vesuvius by Professor Palmieri who observed the eruptions of 1858, 1861, 1868, and 1872 from the Vesuvius"
"B.S. in physics at Colorado State University, and an MS and PhD in applied physics at the California Institute of Technology. An expert on planetary impacts and global catastrophes, Boslough's work on airbursts challenged the conventional view of asteroid collision risk and is now widely accepted by the scientific community. He was the first scientist to suggest that the Libyan Desert Glass was formed by melting due to overhead heating from an airburst. His hypothesis was popularized by the documentaries ""Tutunkhamun's Fireball"" (BBC), (recipient of Discover Magazine's Top 100 Science Stories of 2006) and Ancient Asteroid National Geographic. which provided"
"Greek ""tektos"", molten) are not themselves meteorites, but are rather natural glass objects up to a few centimeters in size that were formed—according to most scientists—by the impacts of large meteorites on Earth's surface. A few researchers have favored tektites originating from the Moon as volcanic ejecta, but this theory has lost much of its support over the last few decades. In March 2015, NASA scientists reported that, for the first time, complex organic compounds found in DNA and RNA, including uracil, cytosine and thymine, have been formed in the laboratory under outer space conditions, using starting chemicals, such as"
"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 is usually a light green, although color can vary. It is mildly radioactive but safe to handle. In the late 1940s and early 1950s,"