| 单词 | zircon |
| 例句 | Bournonite; apatite on muscovite; natural zircon in a spray of colors; dozens more minerals he cannot name. All the Light We Cannot See 2014-05-06T00:00:00Z One night he reads a paper in the scientific journal Nature about the discovery of some 4.27-billion-year-old zircon crystals in remote Western Australia. Barry Lopez Travels to the Ends of the Earth, Seeking Glimmers of Hope 2019-04-02T04:00:00Z Not something you hear every day, especially when you have no clue what a zircon is. Australia is a land of firsts: First life, first burger with beetroot and pineapple 2019-02-23T05:00:00Z "So then are zircons thick on the ground?" Australia is a land of firsts: First life, first burger with beetroot and pineapple 2019-02-23T05:00:00Z For the plebeians among us, there is the sterling silver and zircon Tiara Collection, starting at under $200. J. Estina, a Luxury Jewelry Line From Korea, Opens in the Plaza - Scouting Report 2011-12-21T23:03:30Z By studying the atomic clues trapped in a crystal of zircon, one of the oldest mineral to survive from the moon’s formation, scientists have determined that the moon is at least 4.46 billion years old. The moon is even older than we thought 2023-10-23T04:00:00Z When that lunar magma ocean cooled, that's when the zircon crystals could finally form, locking in chemical signatures that the Field Museum scientists can now measure with radiometric dating technology. Looking good for her age: Moon may be 40 million years older than we thought, analysis reveals 2023-10-23T04:00:00Z The atom-by-atom analysis enabled researchers to count how many atoms in the zircon crystals have undergone radioactive decay. The Moon is 40 million years older than previously thought 2023-10-23T04:00:00Z That age needed to be confirmed through another method because of a potential complication involving lead atoms if defects existed in the zircon crystal structure. Rock collected by Apollo 17 astronaut in 1972 reveals moon's age 2023-10-23T04:00:00Z The crown glitters with stones including tourmalines, white and yellow topazes, rubies, amethysts, sapphires, garnet, peridot, zircons, spinel and aquamarines. 5 things to look for during King Charles III’s coronation 2023-05-05T04:00:00Z New minerals crystallized out of the rock melt, and one of the last to form were zircons. The moon is even older than we thought 2023-10-23T04:00:00Z A jargoon is a kind of smoky zircon. Coronation crown taken from Tower to be resized for King Charles III 2022-12-05T05:00:00Z "When the surface was molten like that, zircon crystals couldn't form and survive," Heck said. The Moon is 40 million years older than previously thought 2023-10-23T04:00:00Z Australia is the world’s top producer of lithium and rutile and the second-largest producer of zircon and rare earth elements. Japan, Australia upgrade security pact against China threat 2022-10-22T04:00:00Z Knowing this light comes from a He-Ne laser and has a wavelength of 633 nm in air, is the substance zircon or diamond? College Physics for AP Courses 2015-08-12T00:00:00Z They also capture uranium isotopes from the environment as they form, which serve as a timer that starts from the moment the zircons crystallize. The moon is even older than we thought 2023-10-23T04:00:00Z Determine the number of atoms and the mass of zirconium, silicon, and oxygen found in 0.3384 mol of zircon, ZrSiO4, a semiprecious stone. Chemistry 2019-02-14T00:00:00Z Because the crystals must have formed after the magma ocean cooled, determining the age of the zircon crystals would reveal the minimum possible age of the Moon. The Moon is 40 million years older than previously thought 2023-10-23T04:00:00Z In addition to olivine, other common neosilicate minerals include garnet, topaz, kyanite, and zircon. An Introduction to Geology 2017-01-01T00:00:00Z Slices of those rocks went to the lab of Gavin Kenny, a geochronologist at the Swedish Museum of Natural History, who sifted out crystals of the mineral zircon smaller than grains of sand. Controversial impact crater under Greenland’s ice is surprisingly ancient 2022-03-08T05:00:00Z Both Heck and Barboni wouldn’t be surprised if future researchers find an older zircon that produces an even older age for the moon. The moon is even older than we thought 2023-10-23T04:00:00Z Rio Tinto's South African subsidiary Richards Bay Minerals extracts and refines heavy mineral sands and produces ilmenite, rutile, and zircon at its site in northern KwaZulu-Natal province. South Africa urges Rio Tinto workers to report cases of discrimination 2022-02-03T05:00:00Z By revealing the age of these telltale zircon crystals -- found hidden within dust collected from the Moon -- researchers were able to piece together the timeline of the Moon's formation. The Moon is 40 million years older than previously thought 2023-10-23T04:00:00Z Because beach sands, past or present, are so highly evolved, the amount of grain weathering can be discerned using the minerals zircon, tourmaline, and rutile. An Introduction to Geology 2017-01-01T00:00:00Z Some of zircon crystals were “shocked”—inscribed with linear fracture patterns that are the hallmark of an impact. Controversial impact crater under Greenland’s ice is surprisingly ancient 2022-03-08T05:00:00Z By counting the number of lead atoms that form and the uranium atoms that remain, researchers can work out how much time has passed since the zircons hardened from molten material. The moon is even older than we thought 2023-10-23T04:00:00Z Titanium concentrations in 4-billion-year-old zircon crystals from Western Australia suggest they formed underwater. Ancient Earth was a water world 2021-03-09T05:00:00Z Tang realized that the chemistry of the zircon crystals from the Tibetan samples changed in step with the continental thickness at the time their parent rocks formed. Earth’s mountains may have mysteriously stopped growing for a billion years 2021-02-11T05:00:00Z Native gold, native platinum, zircon, ilmenite, rutile, magnetite, diamonds, and other gemstones can be found in placers. An Introduction to Geology 2017-01-01T00:00:00Z Trace amounts of radioactive uranium are present in the zircon, and its decay into lead provides an accurate way to date the samples. Controversial impact crater under Greenland’s ice is surprisingly ancient 2022-03-08T05:00:00Z The study authors probed the zircons embedded in a lunar rock sample collected during Apollo 17 in 1972, and they constructed a 3D map of the atoms. The moon is even older than we thought 2023-10-23T04:00:00Z We processed the samples by grinding and extracting zircon crystals, which can preserve unstable isotopes of uranium. The Real Dilophosaurus Would Have Eaten the Jurassic Park Version for Breakfast 2020-12-15T05:00:00Z Tang was analyzing granite rocks from the Himalaya of southern Tibet when he noticed a curious pattern in their crystals of the mineral zircon. Earth’s mountains may have mysteriously stopped growing for a billion years 2021-02-11T05:00:00Z Geologists have used zircon grains to do some amazing studies that illustrate how scientific conclusions can change with technological advancements. An Introduction to Geology 2017-01-01T00:00:00Z The impact kicked out the lead impurities in the shocked zircons, effectively resetting the uranium clock. Controversial impact crater under Greenland’s ice is surprisingly ancient 2022-03-08T05:00:00Z Depending on where one looked, there was a chance that they might come across these unevenly distributed lead sites and miscalculate the zircon’s age. The moon is even older than we thought 2023-10-23T04:00:00Z That’s based on the ages of 51 zircon crystals found within the meteorite that likely formed under the extreme heat of an impact. Famed meteorite reveals early water on Mars—and an early outer space bombardment 2020-11-16T05:00:00Z But clues etched into tiny zircon crystals that formed deep in the Earth suggest that plate tectonics didn't always work the same way it does today. Earth’s mountains may have mysteriously stopped growing for a billion years 2021-02-11T05:00:00Z The zircon grains were incorporated into metasedimentary host rocks, sedimentary rocks showing signs of having undergone partial metamorphism. An Introduction to Geology 2017-01-01T00:00:00Z As zircon forms in cooling magma, its crystal structure contains uranium but no lead. How Do Scientists Determine the Ages of Human Ancestors, Fossilized Dinosaurs and Other Organisms? 2020-08-04T04:00:00Z “In this zircon, everything was homogeneous, so we didn't even have to worry about that,” says study author Philipp Heck, a cosmochemist at the Field Museum and the University of Chicago. The moon is even older than we thought 2023-10-23T04:00:00Z The early impacts recorded by the team’s zircons, which hit in two distinct peaks only 30 million years apart, are only circumstantial evidence that the gas giants shifted at the time. Famed meteorite reveals early water on Mars—and an early outer space bombardment 2020-11-16T05:00:00Z Researchers have found zircons that formed soon after Earth’s birth nearly 4.4 billion years ago. Earth’s mountains may have mysteriously stopped growing for a billion years 2021-02-11T05:00:00Z The host rocks were not very old but the embedded zircon grains were created 4.4 billion years ago and survived the subsequent processes of weathering, erosion, deposition, and metamorphism. An Introduction to Geology 2017-01-01T00:00:00Z The researchers focused on hafnium, a trace element found in the mineral zircon, a component of sand. The Romans Called it ‘Alexandrian Glass.’ Where Was It Really From? 2020-07-31T04:00:00Z An analysis of zircon crystals more than 4 billion years old from the Jack Hills in Western Australia provided an early test. Diamond microscope reveals slow crawl of Earth’s ancient crust 2020-04-22T04:00:00Z The researchers determined the crater’s age by examining tiny crystals of the minerals monazite and zircon formed in the asteroid impact. Did asteroid that hit Australia help thaw ancient 'snowball Earth'? 2020-01-23T05:00:00Z The everlasting quality of zircons, however, allows scientists to glimpse a much more complete story of our planet’s past. Earth’s mountains may have mysteriously stopped growing for a billion years 2021-02-11T05:00:00Z The scientists were able to determine the age of the impact crater, which is not visible to the eye, by testing the minerals zircon and monazite that were "shock recrystallized." Earth's oldest asteroid strike may have ended 'Snowball Earth' 2020-01-22T05:00:00Z One possibility is that the zircons containing certain isotopic ratios are bigger, denser, or bulkier, which affects their movement, Dr. Barfod said. The Romans Called it ‘Alexandrian Glass.’ Where Was It Really From? 2020-07-31T04:00:00Z Traditional paleomagnetic measurements using superconducting sensors had found faint fields preserved in the zircons, a clue that Earth had a magnetic field half a billion years earlier than expected. Diamond microscope reveals slow crawl of Earth’s ancient crust 2020-04-22T04:00:00Z The scientists were looking for grains of zircon and monazite, tough minerals that survive for billions of years and, crucially, incorporate uranium and thorium atoms into their crystalline structure. Earth’s Oldest Asteroid Impact Found in Australia 2020-01-21T05:00:00Z They accrued data from previously studied zircons from around the globe—more than 14,000 in all—and plotted the chemical changes over time. Earth’s mountains may have mysteriously stopped growing for a billion years 2021-02-11T05:00:00Z Geologists date events using “isotopic clocks” in minerals like zircon and monazite. The world’s oldest asteroid strike in Western Australia may have triggered a global thaw 2020-01-21T05:00:00Z To determine when the asteroid hit Earth, the team examined tiny zircon and monazite crystals in the rocks. Earth's oldest asteroid crater found in Australia 2020-01-21T05:00:00Z But the superconducting sensors could measure only the average field across the zircons, which are as small as motes of dust. Diamond microscope reveals slow crawl of Earth’s ancient crust 2020-04-22T04:00:00Z Based on measurements of 39 zircon and monazite crystals, Dr. Erickson and his team calculated that the Yarrabubba impact occurred 2.229 billion years ago, with an uncertainty of 5 million years. Earth’s Oldest Asteroid Impact Found in Australia 2020-01-21T05:00:00Z Aside from those contested Australian zircons, the oldest known evidence of Earth’s magnetic field — rocks in South Africa — dates to around 3.5 billion years ago. Greenland rocks suggest Earth's magnetic field is older than we thought 2019-12-09T05:00:00Z A closer examination showed that the zircons also bore a cloudy appearance and deformed surface, two signs the minerals were kicked through the air and water by a great impact. America's largest asteroid impact left a trail of destruction across the eastern US 2019-08-16T04:00:00Z The study analyzed some of the oldest known Martian minerals, looking at zircon and baddeleyite grains seen in Martian meteorites, utilizing electron microscopy and atom probe tomography. Mars may have hosted life earlier than Earth did, study says 2019-06-26T04:00:00Z It’s also known to be built on an all-new, Google-built kernel called “zircon,” formerly known as “magenta,” and not the Linux kernel that forms the foundation of Android and Chrome OS. Google is starting to reveal the secrets of its experimental Fuchsia OS 2019-05-09T04:00:00Z Among the debris that rained down were bentonite and zircon crystals, whose magnetic properties provided Olsen and Kent with a crucial corroborative clue. A Geological "Orrery" Could Reveal Planetary Dynamics in Deep Time 2019-04-09T04:00:00Z In 2015, Tarduno and his colleagues reported finding signs of Earth’s magnetic field from more than 4 billion years ago, inside zircon crystals from Australia. Greenland rocks suggest Earth's magnetic field is older than we thought 2019-12-09T05:00:00Z By comparing the ratios of specific helium, thorium and uranium isotopes in each mineral sample, the researchers calculated approximately how long ago the zircon crystals solidified and started to decay. America's largest asteroid impact left a trail of destruction across the eastern US 2019-08-16T04:00:00Z A team including Keller and led by Blair Schoene, a geochronologist at Princeton, looked at zircon crystals trapped between layers of basalt. Did volcanic eruptions help kill off the dinosaurs? 2019-02-21T05:00:00Z Trace elements in the rock’s minerals, which are a granitelike mix of quartz, feldspar, and zircon crystals, provided clues to its origin. Ancient Earth rock found on the moon 2019-01-29T05:00:00Z The Earth’s magnetic field sporadically flips, Kent explains, and those reversals are recorded in the zircon crystals in the sediment. A Geological "Orrery" Could Reveal Planetary Dynamics in Deep Time 2019-04-09T04:00:00Z Other scientists recently challenged that paper, saying the magnetic minerals inside the zircons could not be accurately dated1. Greenland rocks suggest Earth's magnetic field is older than we thought 2019-12-09T05:00:00Z Not only is zircon commonly found in tektites, but it is also a choice mineral for radiometric dating, thanks to some of its radioactive elemental components. America's largest asteroid impact left a trail of destruction across the eastern US 2019-08-16T04:00:00Z The oldest known fragment of Earth rock is a zircon crystal from Western Australia. 4bn-year-old 'Earth rock' found in Apollo 14 crew's moon haul 2019-01-25T05:00:00Z By measuring uranium and its decay products in the zircons, the team dated the formation of the rock, while titanium levels helped reveal the temperature and pressure at the time. Ancient Earth rock found on the moon 2019-01-29T05:00:00Z On the basis of evidence from tiny, almost indestructable mineral crystals called zircons, researchers think a modest amount of dry land was occasionally doused with rain. How an ancient cataclysm may have jump-started life on Earth 2019-01-10T05:00:00Z It’s likely both teams have at least one hand on the truth, adds Lee, who contributed to the zircon paper. Rise of carbon dioxide–absorbing mountains in tropics may set thermostat for global climate 2018-12-28T05:00:00Z The growth of the continental crust: constraints from zircon Hf-isotope data. Rapid emergence of subaerial landmasses and onset of a modern hydrologic cycle 2.5 billion years ago 2018-05-22T04:00:00Z The scientists studied tiny crystals of zircon in the tektites and looked at their geometrical orientation. Glassy debris points to relatively recent asteroid impact in southeast Asia 2018-01-03T05:00:00Z Here, Kring says, there’s no doubt that the rock and its zircons formed at the same time. Ancient Earth rock found on the moon 2019-01-29T05:00:00Z The date of the rocks in the region is based on measurements of tiny particles of a mineral called zircon. Carbon found in 3.95bn-year-old rocks is remnant of ancient life – researchers 2017-09-27T04:00:00Z The study used ages from thousands of zircons, durable crystals that can indicate volcanic activity, to show that upticks in volcanic emissions were the dominant force driving the planet’s warm periods. Rise of carbon dioxide–absorbing mountains in tropics may set thermostat for global climate 2018-12-28T05:00:00Z He based his hypothesis on tiny sparkly minerals called zircon that he found on Mauritius. In the Indian Ocean, Fragments of a Continent Where They Should Not Be 2017-02-03T05:00:00Z Barboni said she is studying more zircons from Apollo 14 samples, but doesn’t expect it to change her estimate of 4.51 billion years for the moon’s age, possibly 4.52 billion years at the most. The moon is older than scientists thought 2017-01-13T05:00:00Z The scientists conducted uranium-lead dating on fragments of the mineral zircon extracted from Apollo 14 lunar samples. Scientists: Moon over the hill at 4.51 billion years old 2017-01-11T05:00:00Z Chemical signatures found in hardy microscopic crystals called zircons point to a beginning about 4.1 billion years ago. Hints of oldest fossil life found in Greenland rocks 2016-08-31T04:00:00Z A global analysis of detrital zircons suggests that volcanism is the primary driver of very long-term climate oscillations. Continental arc volcanism as the principal driver of icehouse-greenhouse variability | Science 2016-04-21T04:00:00Z But when Dr. Ashwal dated the zircon crystals he found on Mauritius, he discovered they were around three billion years old, much older than any oceanic crust and much, much older than Mauritius. In the Indian Ocean, Fragments of a Continent Where They Should Not Be 2017-02-03T05:00:00Z The scientists conducted uranium-lead dating on fragments of the mineral zircon extracted from Apollo 14 lunar samples. The moon is older than scientists thought 2017-01-13T05:00:00Z Those zircons crystallized about 234 million years ago, the team’s analyses suggest. Dinosaurs evolved much faster than previously thought 2015-12-07T05:00:00Z A total of 656 of these zircons were found to contain dark specks, or inclusions. Early Origins for Life Raises Major Planetary Puzzles 2015-10-22T04:00:00Z A global analysis of detrital zircons suggests that volcanism is the primary driver of very long-term climate oscillations. Continental arc volcanism as the principal driver of icehouse-greenhouse variability | Science 2016-04-21T04:00:00Z For one, he says, researchers need to settle some important debates, like whether the inclusions in Hadean zircons truly preserve original material, or if they’ve been altered, for example, during a later bout of metamorphism. Scientists may have found the earliest evidence of life on Earth 2015-10-19T04:00:00Z Researchers examined tiny grains of the mineral zircon from western Australia's Jack Hills and chemically dated them to when Earth was barely 400 million years old. Study: Life may have sprung up earlier on Earth, raising hopes for life elsewhere in universe 2015-10-19T04:00:00Z And older sediments below the fossils contain zircons that crystallized about 236 million years ago, the researchers report online today in the Proceedings of the National Academy of Sciences. Dinosaurs evolved much faster than previously thought 2015-12-07T05:00:00Z Thousands of tiny zircon crystals were separated by hand from the bulk rock, as magnetic separation techniques would have contaminated the samples. Earth magnetic shield is older than previously thought - BBC News 2015-07-31T04:00:00Z The study focused on a mineral called magnetite contained inside ancient zircon crystals from Australia's Jack Hills. Earth's 'magnetic personality' much older than previously thought 2015-07-30T04:00:00Z For now, scientists must make do with zircons, the only materials that preserve any record—however cryptic—of the Hadean. Scientists may have found the earliest evidence of life on Earth 2015-10-19T04:00:00Z The magnetometer, which uses cryogenically cooled superconducting sensors, identified the strength and the orientation of the Earth’s ancient magnetic field when it was “frozen” into magnetite crystals within the zircons. Oldest rock crystals point to ancient magnetic shield for Earth 2015-07-30T04:00:00Z A younger volcanic deposit lying in the rock above these fossils includes zircons, tiny bits of silicate mineral that often contain trace amounts of uranium. Dinosaurs evolved much faster than previously thought 2015-12-07T05:00:00Z An iron ion micro-probe was used to determine the age of the zircon. Earth magnetic shield is older than previously thought - BBC News 2015-07-31T04:00:00Z Magnetite preserves a record of magnetic field strength at the time the mineral was trapped in the zircon. Earth's 'magnetic personality' much older than previously thought 2015-07-30T04:00:00Z She says researchers must make a concerted effort to find more Hadean carbon in Jack Hills zircons and see if it too has potentially biological origins. Scientists may have found the earliest evidence of life on Earth 2015-10-19T04:00:00Z So the team cut a thin-section out of their 3-billion-year-old conglomerate sample, and showed that the magnetic orientations of areas containing zircons were all oriented randomly. Oldest rock crystals point to ancient magnetic shield for Earth 2015-07-30T04:00:00Z The scientists used a high-resolution magnetometer to measure faint magnetic signals of iron-bearing minerals trapped inside 25 zircons. Earth's ancient magnetic field just got a lot older 2015-07-29T04:00:00Z The group is also working on samples from Zimbabwe, which are thought to hold zircons with an age of 3.8 billion years old. Earth magnetic shield is older than previously thought - BBC News 2015-07-31T04:00:00Z But the widest use of zircon, which is generally mined in association with titanium minerals that are sometimes called mineral sands, is in the more mundane applications of ceramic tiles. There's Trouble On The Stock Market But China's Bathrooms Are In Sparkling Condition 2015-07-28T04:00:00Z And although they barely span the width of a human hair, zircons are nearly indestructible. Scientists may have found the earliest evidence of life on Earth 2015-10-19T04:00:00Z They have analyzed zircons from the same area of the Jack Hills. Oldest rock crystals point to ancient magnetic shield for Earth 2015-07-30T04:00:00Z To look deeper into Earth's past, the team went to the Jack Hills region of Western Australia, which is famous for its four-billion-year-old zircon crystals. Earth's ancient magnetic field just got a lot older 2015-07-29T04:00:00Z "To get older data, we need to be sure that the zircons have been preserved and have not been reheated above their Curie temperature." Earth magnetic shield is older than previously thought - BBC News 2015-07-31T04:00:00Z The Chinese ceramics market is so important to the handful of miners which produce the mineral that they routinely analyse how much zircon is being used on floor tiles, baths and hand basins. There's Trouble On The Stock Market But China's Bathrooms Are In Sparkling Condition 2015-07-28T04:00:00Z In fact, although the oldest rocks on Earth date back only 4 billion years, researchers have found zircons up to 4.4 billion years old. Scientists may have found the earliest evidence of life on Earth 2015-10-19T04:00:00Z Weiss also worries about using a lack of discrepancies in the uranium-lead system to justify the integrity of the zircons through their first billion years. Oldest rock crystals point to ancient magnetic shield for Earth 2015-07-30T04:00:00Z The oldest Australian zircons, which date to 4.4 billion years ago, contain a limited and confusing magnetic record. Earth's ancient magnetic field just got a lot older 2015-07-29T04:00:00Z The evidence is found in tiny sand grains of the mineral zircon radiometrically dated to as old as 4.4 billion years ago. Life Ain't Easy: What Would Make an Exoplanet "Earth-Like"? [Excerpt] 2015-04-30T04:00:00Z China’s stock market might be under pressure, and doubts raised about its rate of economic growth, but if the latest zircon import data is a guide the country’s bathrooms are in sparkling condition. There's Trouble On The Stock Market But China's Bathrooms Are In Sparkling Condition 2015-07-28T04:00:00Z The clues lie hidden in microscopic flecks of graphite—a carbon mineral—trapped inside single large crystals of zircon. Scientists may have found the earliest evidence of life on Earth 2015-10-19T04:00:00Z Using optical microscopes, his team painstakingly searched for zircons about 0.2 millimeters across. Oldest rock crystals point to ancient magnetic shield for Earth 2015-07-30T04:00:00Z The Jack Hills zircons show that a magnetic field existed as early as 4 billion years ago, fluctuating in strength from a value similar to today's — around 25 microteslas — to about 12% of that. Earth's ancient magnetic field just got a lot older 2015-07-29T04:00:00Z Crystals of zircon form in magma with trace amounts of uranium inside. Did a massive volcanic eruption in India kill off the dinosaurs? 2014-12-11T05:00:00Z As a general rule the better the glaze on a tile, or other ceramic products such as bathroom fittings, the higher the zircon content. There's Trouble On The Stock Market But China's Bathrooms Are In Sparkling Condition 2015-07-28T04:00:00Z The mere presence of these minerals does not prove life existed when the zircons formed, but it does provide the opportunity to look for it. Scientists may have found the earliest evidence of life on Earth 2015-10-19T04:00:00Z The team found several thousand zircons in the sample and selected several hundred that lacked cracks and seemed the most pristine. Oldest rock crystals point to ancient magnetic shield for Earth 2015-07-30T04:00:00Z In these regions they found zircons, hardy little crystals that are valued because they suck up enough radioactive uranium to be used for dating. Feature: A castaway from ancient Mars 2014-11-25T05:00:00Z By age dating zircons—tiny crystals that typically include uranium as a trace element—in the rocks, Langer and his colleagues estimate that the sediments were deposited about 200.7 million years ago. New meat-eating dinosaur lived in the wake of a mass extinction 2014-10-07T04:00:00Z The simulations predict a spike in asteroid impacts around 4.1 billion years ago, which correlates with the age of the majority of known zircon samples. Asteroids wreaked havoc on early Earth 2014-07-29T04:00:00Z But partly thanks to the wealth of information revealed by the Jack Hills zircons in recent years, scientists have come to see the early Earth as much milder and more amenable to life. Scientists may have found the earliest evidence of life on Earth 2015-10-19T04:00:00Z The team sent the best zircons off to another laboratory to get age dates. Oldest rock crystals point to ancient magnetic shield for Earth 2015-07-30T04:00:00Z It would also mean that, just a hundred million years after Mars itself coalesced as a molten ball of rock, its crust had cooled enough to support magma chambers in which zircons could form. Feature: A castaway from ancient Mars 2014-11-25T05:00:00Z The zircons are randomly distributed and interlaced with their surrounding minerals — they couldn't have grown from the heat of impact later than their neighbors, she said. Earth's Oldest and Biggest Crater Yields New Secrets 2014-04-29T22:00:00Z The authors suggest that the zircons could have been created when large portions of Earth’s surface were buried by asteroid impacts, an idea that Abramov says “has a lot of merit”. Asteroids wreaked havoc on early Earth 2014-07-29T04:00:00Z As the sediments melted to form magma, the elevated temperatures and pressures transformed the carbon into graphite, which eventually found its way into a zircon crystal. Scientists may have found the earliest evidence of life on Earth 2015-10-19T04:00:00Z Then they had worry about the zircons’ first billion years or so of existence. Oldest rock crystals point to ancient magnetic shield for Earth 2015-07-30T04:00:00Z The gem is a zircon crystal, which are already known to be the oldest material formed on Earth. 'Oldest piece of Earth's crust' found 2014-02-25T13:59:59Z Others suggested the young zircons could have crystallized in pre-existing rocks from the impact's heat. Earth's Oldest and Biggest Crater Yields New Secrets 2014-04-29T22:00:00Z The zircon was found in sandstone in the Jack Hills region of Western Australia. Crystal is 'oldest scrap of crust' 2014-02-24T12:36:13Z “Hopefully we didn’t just chance on the one freak zircon that had graphite in it,” she says. Scientists may have found the earliest evidence of life on Earth 2015-10-19T04:00:00Z At a meeting of the American Geophysical Union in December 2014, a collaborator of Weiss’s used the diamond-sensor magnetometer to show the specific part of an ancient zircon where the magnetization may lie. Oldest rock crystals point to ancient magnetic shield for Earth 2015-07-30T04:00:00Z Uranium decays into lead, and counting the ratio of the two elements provides an age estimate for the zircons. Worst Mass Extinction Ever Took Only 60,000 Years 2014-02-11T11:10:00Z The impact launched partially melted fragments of the crystallized lava up through the atmosphere and into space, glossing the baddeleyite grains with rims of molten zircon. Solved: The Mystery of the Martian Meteorites 2013-07-26T18:45:00.760Z This would have given the impression the zircon was older than it really is. Crystal is 'oldest scrap of crust' 2014-02-24T12:36:13Z To fill this gap, Olsen and his coauthors—including Terrence Blackburn, a fellow at the Carnegie Institute—embarked on a years-long rock hunt in search of zircon crystals trapped in the basalt. Mega-Eruption: Scientists Connect a Mass Extinction to a Major Lava Flow 2013-04-04T13:05:22Z It turned out it was coming from ferromagnetic materials coating the surface of the zircons, not from magnetites in the interior of the crystal. Oldest rock crystals point to ancient magnetic shield for Earth 2015-07-30T04:00:00Z The team chose to collect sand, rather than pulverize local rocks, to ensure that zircons inadvertently trapped in rock-crushing equipment from previous studies did not contaminate their fresh samples. Long-Lost Continent Found under the Indian Ocean 2013-02-25T16:15:14.523Z But its beach sands contained not just fragments of eroded lava but also zircons, a mineral associated with continental crust. Lost Land Beneath the Waves 2013-02-24T18:00:00Z The zircons found at Jack Hills are tough pieces of old rock that have been incorporated into the newer, reworked material. Crystal is 'oldest scrap of crust' 2014-02-24T12:36:13Z When zircon crystals form, they lock within them a large helping of uranium, and over time, the uranium decays at a regular rate into lead. Mega-Eruption: Scientists Connect a Mass Extinction to a Major Lava Flow 2013-04-04T13:05:22Z Now the zircons sit within quartz pebbles within a mish-mashed stone, called a conglomerate, that formed about 3 billion years ago. Oldest rock crystals point to ancient magnetic shield for Earth 2015-07-30T04:00:00Z Jamtveit and his colleagues suggest that rocks containing the wayfaring zircons originated in ancient fragments of continental crust located beneath Mauritius. Long-Lost Continent Found under the Indian Ocean 2013-02-25T16:15:14.523Z The magma, they suggest, punched its way through pieces of preexisting continental crust on the seafloor, and in the process it tore off zircons and incorporated them into the basalt lava. Lost Land Beneath the Waves 2013-02-24T18:00:00Z However, using two sensitive analytical techniques, Prof Valley and colleagues were able to show the zircon's internal uranium-lead clock was showing a true age. Crystal is 'oldest scrap of crust' 2014-02-24T12:36:13Z From that time, the oldest materials we have are tiny crystals, bits of the mineral zircon. Scratching the surface of the Moon 2012-12-08T08:10:15Z Typically, magnets are used to sift for zircons, which contain magnetizable minerals such as magnetite—but that would have altered any remanent field in the zircons. Oldest rock crystals point to ancient magnetic shield for Earth 2015-07-30T04:00:00Z “There’s no obvious local source for these zircons,” says Conall Mac Niocaill, a geologist at the University of Oxford, UK, who was not involved in the research. Long-Lost Continent Found under the Indian Ocean 2013-02-25T16:15:14.523Z Schmitt and his colleagues dated zircon crystals in the hardened lava of the buttes with a relatively new technique, a "helium clock" that starts ticking once the minerals begin cooling at the surface. Salton Sea Volcano Mystery Solved 2012-10-28T20:17:14.297Z Rather than zircon, the team's target was crystals of the common mineral quartz. Supervolcanoes 'quicker to blow' 2012-05-30T22:00:21Z It's a resistant mineral so the rock can be melted and eroded, and all we have left are these zircons. Scratching the surface of the Moon 2012-12-08T08:10:15Z Tarduno says he is glad that Weiss is pushing the limits of these measurements, but does not think that that particular result says anything about the zircons his team selected. Oldest rock crystals point to ancient magnetic shield for Earth 2015-07-30T04:00:00Z One of these zircons was at least 1.97 billion years old. Long-Lost Continent Found under the Indian Ocean 2013-02-25T16:15:14.523Z Decay of uranium isotopes in zircon crystals show magma built up underneath the volcanoes for thousands of years before the latest eruption, the study shows. Salton Sea Volcano Mystery Solved 2012-10-28T20:17:14.297Z Many accessory minerals such as tourmaline and zircon have been identified also, while augite, hornblende and other volcanic minerals occur in varying proportion as in all the sediments of the open sea. Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 1 "Gichtel, Johann" to "Glory" 2012-01-11T03:00:20.463Z Illegal logging and gold and zircon mining are other threats. Green Blog: In a Mini-Eden for Threatened Orangutans 2012-01-06T17:50:22Z Mica, iron oxides, apatite, zircon, epidote and hornblende may also be present in small amount. Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 7 "Gyantse" to "Hallel" 2011-12-26T03:00:11.613Z They propose that geologically recent volcanic eruptions brought shards of the crust to Earth’s surface, where the zircons eroded from their parent rocks to pepper the island’s sands. Long-Lost Continent Found under the Indian Ocean 2013-02-25T16:15:14.523Z A high proportion of zircon inclusions are made up of phosphate minerals called apatite, Williams says. Earth's 'Time Capsules' May Be Flawed 2011-11-17T19:07:05Z Apatite, zircon and iron oxides, in small crystals, are always present. Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 3 "Gordon, Lord George" to "Grasses" 2011-11-13T03:00:13.177Z The Zircon.—The zircon is a very beautiful stone, varying in colour, like the topaz, from red and yellow to green and blue. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 5 "Gassendi, Pierre" to "Geocentric" 2011-09-02T02:00:20.450Z Mineral sands, such as zircon, sit under a tarpaulin. Petri-dish economies: Everybody needs good neighbours 2011-03-31T10:44:34Z Informally, this is known as “zapping” the zircons. Scientist at Work: Rocks, Zircon Zapping and a Big Shrimp 2011-01-07T21:02:35Z "This was a big surprise to us," Rasmussen says, especially because the zircons themselves ranged in age from 3.34 billion and 4.24 billion years old. Earth's 'Time Capsules' May Be Flawed 2011-11-17T19:07:05Z The accessory minerals of these rocks are principally oligoclase, muscovite, apatite and zircon. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 2 "Anjar" to "Apollo" H. Sainte-Claire Deville formed the zircon artificially by passing silicon fluoride at a red heat over the oxide zirconia in a porcelain tube. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 5 "Gassendi, Pierre" to "Geocentric" 2011-09-02T02:00:20.450Z Other minerals, except apatite, zircon and magnetite, are typically absent. Encyclopaedia Britannica, 11th Edition, Volume 4, Slice 3 "Borgia, Lucrezia" to "Bradford, John" To work on zircons at the A.N.U. facility, we will crush the rocks, separate the zircon crystals, mount them in epoxy disks and polish them so that cross sections of their interiors are revealed. Scientist at Work: Rocks, Zircon Zapping and a Big Shrimp 2011-01-07T21:02:35Z These zircons ended up in the Jack Hills rocks after eroding from rocks that were even more ancient, and the researchers painstakingly sorted the individual crystals from other bits of minerals. Earth's 'Time Capsules' May Be Flawed 2011-11-17T19:07:05Z Among the commonest associates of the diamond are quartz, topaz, tourmaline, rutile, zircon, magnetite, garnet, spinel and other minerals which are common accessory constituents of granite, gneiss and the crystalline schists. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 4 "Diameter" to "Dinarchus" Octahedral crystals of zircon are then produced, which have the same crystalline form, appearance and optical qualities as the natural zircon. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 5 "Gassendi, Pierre" to "Geocentric" 2011-09-02T02:00:20.450Z These sediments are fine and tenacious; their principal components, in addition to clay, being small grains of quartz, zircon, tourmaline, hornblende, felspar and iron compounds. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 4 "Cincinnatus" to "Cleruchy" In many cases, zircons grow by an accretionary process akin to the formation of hailstones — the core of the hailstone grows first, followed by successive outer layers. Scientist at Work: Rocks, Zircon Zapping and a Big Shrimp 2011-01-07T21:02:35Z Rather than matching the ages of the zircons, the researchers note, the ages of the inclusions matched the ages of the metamorphic minerals surrounding the zircons. Earth's 'Time Capsules' May Be Flawed 2011-11-17T19:07:05Z The other minerals found in the concentrates are pebbles and fragments of pyrope, zircon, cyanite, chrome-diopside, enstatite, a green pyroxene, mica, ilmenite, magnetite, chromite, hornblende, olivine, barytes, calcite and pyrites. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 4 "Diameter" to "Dinarchus" The peculiar lustre exhibited by the diamond is called adamantine, and is shared to some extent by certain other stones which have a high refractive index and high dispersion, such as zircon. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 5 "Gassendi, Pierre" to "Geocentric" 2011-09-02T02:00:20.450Z It consists of very fine scaly kaolin, larger, shining plates of white mica, grains of quartz and particles of semi-decomposed felspar, tourmaline, zircon and other minerals, which originally formed part of the granite. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 4 "Cincinnatus" to "Cleruchy" Of course, hailstones grow by condensation of water, but zircons most commonly grow by crystallization from a silicate melt at temperatures in excess of 700 degrees Celsius. Scientist at Work: Rocks, Zircon Zapping and a Big Shrimp 2011-01-07T21:02:35Z A total of 485 zircons held inclusions, and about a dozen or so of these contained radioactive trace elements that allowed the researchers to determine their ages. Earth's 'Time Capsules' May Be Flawed 2011-11-17T19:07:05Z In 2007, Senegal signed agreements for major new mining concessions for iron, zircon, and gold with foreign companies. The 2008 CIA World Factbook Other stones of less value—such as topaz, spinel, chrysoberyl, chrysolite, zircon and tourmaline—are sometimes called “fancy stones.” Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 5 "Gassendi, Pierre" to "Geocentric" 2011-09-02T02:00:20.450Z However, in most cases in the trade there is almost no chance of the unexpected presence of a zircon and the luster test is usually sufficient to distinguish the diamond. A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public The ion probe allows us to analyze each part of the zircon separately, giving us a full history of the rock in which it formed. Scientist at Work: Rocks, Zircon Zapping and a Big Shrimp 2011-01-07T21:02:35Z The zirconium silicate, zircon, is a fairly common accessory constituent of granitic rocks and pegmatite veins. The Economic Aspect of Geology In 2007, Senegal signed agreements for major new mining concessions for iron, zircon, and gold with foreign companies. The 2008 CIA World Factbook Brett picked his way, stepping over imitation pearl necklaces, zircon rings, plastic buttons, hearing aids, lipsticks, compacts, corset stays, prosthetic devices, rubber heels, wrist watches, lapel watches, pocket watches with corroded brass chains. It Could Be Anything The author has fooled many diamond experts with an especially fine zircon, for the luster of zircon does approach, though it hardly equals, that of the diamond. A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public Images of zircon in cross section, as imaged by cathodoluminescence detector on a scanning electron microscope. Scientist at Work: Rocks, Zircon Zapping and a Big Shrimp 2011-01-07T21:02:35Z In general the mineral is recovered on a commercial scale only from placers, where it has been concentrated along with other dense, insoluble minerals such as zircon, garnet, ilmenite, and sometimes gold. The Economic Aspect of Geology Fixing in this way a point corresponding to opal, and another representing the character of zircon, draw a straight line from the one to the other. Scientific American Supplement, No. 1082, September 26, 1896 This double nitrate has a specific gravity of 4.7963, therefore such a stone as zircon, which is the heaviest known, will float in it. The Chemistry, Properties and Tests of Precious Stones It is necessary, however, to be sure that we are not being deceived by a yellow zircon, for the latter has considerable "fire" and a keen luster. A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public These zircon crystals are about 100 microns long, and show internal structures related to their growth. Scientist at Work: Rocks, Zircon Zapping and a Big Shrimp 2011-01-07T21:02:35Z The recently developed deposits of Pablo Beach, Florida, may produce important amounts of titanium minerals along with the output of zircon and monazite. The Economic Aspect of Geology Opal, which is a comparatively light mineral, has a low refractive power; zircon or jargoon is a heavy mineral, and has a high refractive power. Scientific American Supplement, No. 1082, September 26, 1896 It is estimated in zircons in the following way:—The powdered substance is fused with bisulphate of potash, and extracted with dilute sulphuric acid. A Text-book of Assaying: For the Use of Those Connected with Mines. It is not to be denied that a fine white zircon, when finely cut, may deceive even one who is familiar with diamonds. A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public To bring us full circle, we will next return to Jeff’s lab to measure the hafnium isotope compositions in these zircons. Scientist at Work: Rocks, Zircon Zapping and a Big Shrimp 2011-01-07T21:02:35Z We see the zircon which composes the nucleus. The Birth-Time of the World and Other Scientific Essays If the zircon is finely ground, 15 minutes are sufficient for this operation. Scientific American Supplement, No. 441, June 14, 1884. "A silver chalice of severe pattern encrusted round the stem with blue zircons," Brother Anthony was chanting in his melodious voice, his eyes bright with the reflection of celestial splendours. The Altar Steps The red zircon, or true hyacinth, is rare. A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public Together, the U-Pb age, oxygen and hafnium isotope data will help us understand when and where within the earth a zircon formed, and what its complete history was preceding its latest stage of formation. Scientist at Work: Rocks, Zircon Zapping and a Big Shrimp 2011-01-07T21:02:35Z The question arises whether the darkened area surrounding the zircon may not be due to the influence of the radioactive substances contained in the zircon. The Birth-Time of the World and Other Scientific Essays Finely ground zircon is quickly rendered soluble if fused with a mixture of potassium borofluoride and potassium carbonate. Scientific American Supplement, No. 441, June 14, 1884. The "Matura Diamonds," which are largely used by the native jewellers, consist of zircon, found in the syenite not only uncoloured, but also of pink and yellow tints, the former passing for rubies. Ceylon; an Account of the Island Physical, Historical, and Topographical with Notices of Its Natural History, Antiquities and Productions, Volume 1 Blue zircon, however, has nearly adamantine luster and considerable fire. A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public Most of the broad summit is comparatively level and thick sown with crystals, quartz, mica, hornblende, feldspar, granite, zircon, tourmaline, etc., weathered out and strewn closely and loosely as if they had been sown broadcast. The Yosemite I know of no analyses ascribing so great an amount of uranium to zircon. The Birth-Time of the World and Other Scientific Essays The activity of the mixture in attacking zircon appears from the following experiment: Two zircon crystals, each weighing � grm., were introduced into the melted mixture and subjected to prolonged heat. Scientific American Supplement, No. 441, June 14, 1884. He was half a winter trying out what he found, from arsenic to zircon. Masters of the Guild Brown zircon, while lacking dichroism, is frequently rich and pleasing in shade, and when well cut is very snappy, the luster being almost adamantine, the dispersion being large, and the refractive index high. A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public Among these black schorl or tourmaline, actinolite, zircon, garnet, and fluor spar are not uncommon; but they are too sparingly dispersed to modify the general aspect of the rock. The Student's Elements of Geology Now we sometimes see zircons in felspars and in quartz, etc., but in no such case is a halo produced. The Birth-Time of the World and Other Scientific Essays The portion insoluble in water is readily dissolved in hydrofluoric acid, and is converted into zircon potassium fluoride. Scientific American Supplement, No. 441, June 14, 1884. In this stratum of gravel an infinite number of small, and for the most part worthless, specimens of gems are found, consisting of sapphire, ruby, emerald, jacinth, tourmaline, chrysoberyl, zircon, cat's-eye, "moonstone," and "star-stone." Eight Years' Wanderings in Ceylon They are also frequently and incorrectly called jacinth or hyacinth, terms which, as we have seen, should be reserved for yellow and red zircon, respectively. A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public The face was of crystal, and engraved Upon it the figures flashed and waved With zircons, and beryls, and amethysts. Sword Blades and Poppy Seed It is common to find haloes developed perfectly in this granite, and having a nucleus of zircon less than 5 x 10-4 cms. in diameter. The Birth-Time of the World and Other Scientific Essays If finely divided zircon is boiled for a long time with caustic lye, it is perceptibly attacked. Scientific American Supplement, No. 441, June 14, 1884. Hence, it is easy to detect zircon by any of these tests if there is reason to suspect that it has been substituted for diamond. A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public Small zircons are found in almost every heavy concentrate, as, for example, in the concentrates of the diamond mines of South Africa, and in those of gold placers in many places. A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public Slight increase in temperature causes many of the zircons from Ceylon to change markedly in color. A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public Most generally it is found to be the mineral zircon. The Birth-Time of the World and Other Scientific Essays It is very probable that in this manner zircon might be entirely dissolved under a pressure of 10 atmospheres. Scientific American Supplement, No. 441, June 14, 1884. Moreover, the luster of zircon is nearly adamantine, so the expert does not miss the cold metallic glitter as he would with any other white stone. A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public We now come to a number of minerals slightly less hard than beryl, but harder than quartz, and zircon is perhaps as hard as any of these, so it will be considered next. A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public A fine white zircon is really prettier than a poor diamond. A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public I may say that it is not probable the zircons are richer in radium than I have assumed. The Birth-Time of the World and Other Scientific Essays Crucibles of nickel seem especially well adapted for the fusion of zircon in caustic alkalies.—Ber. Scientific American Supplement, No. 441, June 14, 1884. It is only when no direct comparison is possible, and when the expert is not suspicious, that a zircon can deceive him. A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public Red zircon, which is rare, is properly called "hyacinth." A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public Some zircons become completely whitened by this treatment. A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public The names hyacinth, jacinth, and jargoon are applied to red, yellow, and colorless zircon in the order as given. A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public Of this mixture four parts are taken to one of zircon, thoroughly mixed, and melted in a platinum crucible at a red heat. Scientific American Supplement, No. 441, June 14, 1884. It would never do to let an expert see your zircon beside even a fair diamond. A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public Other zircons merely become lighter colored and less attractive. A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public A zircon will also similarly separate light and its rear facets also appear double-lined as seen with a lens from the table of the stone. A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public The zircon, for example, is strongly doubly refracting, but shows hardly any dichroism. A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public It is useless to deny that by the unaided eye one might be deceived into thinking that a fine brown zircon was a brown diamond. A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public |
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