| 单词 | magnetite |
| 例句 | Some of the last were concave mirrors made from beautifully polished magnetite. 1491 2005-10-10T00:00:00Z But previous reports show that magnetite subjected only to Earth’s natural magnetic field can still cause an initial, though smaller, bias toward one form of a chiral molecule. ‘Breakthrough’ could explain why life molecules are left- or right-handed 2023-06-13T04:00:00Z There is evidence of a robust trade in pottery and valued materials like obsidian, magnetite, and shells, likely carried out by merchants traveling across the larger region. World History: to 1500 2023-04-19T00:00:00Z Hematite and magnetite can form precipitates from water that has a high concentration of dissolved oxygen. Biology for AP Courses 2022-06-09T00:00:00Z On the other hand, many of the metallic minerals, such as pyrite, hematite, and magnetite, have densities over 5 g/cm3. Physical Geology 2015-01-01T00:00:00Z Igneous rocks containing magnetic minerals like magnetite typically provide the most useful data. An Introduction to Geology 2017-01-01T00:00:00Z To find out, they turned to magnetite, a magnetic mineral that is common in Earth’s crust. ‘Breakthrough’ could explain why life molecules are left- or right-handed 2023-06-13T04:00:00Z Those shifts show whether the rocks contain minerals like magnetite, and radiometric data measures substances like uranium, thorium, and potassium. In Colorado, locals question a survey for critical minerals 2021-11-19T05:00:00Z By adding magnetite to oil, he discovered that he could attract the microplastics in a sample of water and remove the vast majority of them with a magnet. Gen Z on how to save the world: young climate activists speak out 2021-10-17T04:00:00Z The dark grey layers are magnetite and the red layers are hematite. Physical Geology 2015-01-01T00:00:00Z 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 They applied a strong external magnetic field, aligning electron spins in the magnetite and strengthening its magnetism. ‘Breakthrough’ could explain why life molecules are left- or right-handed 2023-06-13T04:00:00Z For some executives it comes on top of cuts to a separate bonus scheme after a cost blowout and delays at Fortescue’s Iron Bridge magnetite project. Fortescue logs record bumper profit, dividend but management bonuses cut 2021-08-30T04:00:00Z Some say the sense relies on cells containing a magnetic iron mineral, magnetite, whereas others invoke a protein in the retina called cryptochrome. Sharks use Earth’s magnetic field to navigate the seas 2021-05-06T04:00:00Z Lovley eventually realized that these one-celled organisms produce long chains of proteins that carry the electrons to nearby rust molecules, which use the charged particles to transform into magnetite. Electricity-Carrying Bacteria Lead to New Applications—and New Questions 2020-12-09T05:00:00Z "The shape of the magnetite grains is still rather distinctive," he said in 2006. We may have found life on Mars 24 years ago 2020-06-13T04:00:00Z When they exposed the magnetite surface to a solution containing an equal mix of right- and left-handed RAO molecules, 60% of those that settled on top were of a single handedness. ‘Breakthrough’ could explain why life molecules are left- or right-handed 2023-06-13T04:00:00Z The mechanism of magnetoreception is only settled for certain bacteria, which harbor magnetite crystals that align with Earth’s magnetic field. Humans—like other animals—may sense Earth's magnetic field 2019-03-18T04:00:00Z In particular Hayabusa-2 will determine whether the darkness of Ryugu's surface is due to it being rich in carbon — as is often assumed — or to small, metallic particles such as magnetite. Daring Japanese mission reaches unexplored asteroid Ryugu 2018-06-25T04:00:00Z Micrometeorites contain magnetite, a naturally magnetic form of iron oxide, commonly known as lodestone. Finding micrometeorites in city gutters 2016-12-10T05:00:00Z Yet her most recent work suggests that the magnetite could have formed by neither thermal decomposition nor shock waves. We may have found life on Mars 24 years ago 2020-06-13T04:00:00Z Bands of heat-absorbing black sand, primarily magnetite, together with topography that limits air movement help explain the blazing temperatures, Djamali says. The incredible ecosystem of Earth’s hottest spot 2016-12-15T05:00:00Z Bird beaks and fish snouts also contain magnetite, as does the human brain. Humans—like other animals—may sense Earth's magnetic field 2019-03-18T04:00:00Z The most convincing evidence that the meteorite contained fossils was the presence of magnetite crystals, which have a similar size and chemical composition as those of crystals created by certain bacteria on Earth. NASA’s Bold Plan to Hunt for Fossils on Mars Maher says the particles found are "strikingly similar" to magnetite nanospheres abundant in airborne pollution found next to busy roads, formed by combustion or frictional heating from vehicle engines or brakes. Possible air pollution link to Alzheimer's 2016-09-14T04:00:00Z In this case, their attention was grabbed by signs of magnetite, a magnetic mineral made of iron and oxygen that they knew was normally produced only by bacteria. We may have found life on Mars 24 years ago 2020-06-13T04:00:00Z The high levels of magnetite, an iron oxide, were found in brain tissue from people in the U.K. and Mexico. Health Highlights: Sept. 6, 2016 2016-09-06T04:00:00Z But Kirschvink’s team contends its new results tip the scales in favor of magnetite. Humans—like other animals—may sense Earth's magnetic field 2019-03-18T04:00:00Z But in recent years, geologists have discovered that shockwaves, like those the space rock must have been exposed to when it slammed into Earth, can also produce magnetite crystals. NASA’s Bold Plan to Hunt for Fossils on Mars Detailed analysis of the six most magnetic brain samples showed the majority of the magnetite particles to be spherical, distinguishing them from the angular magnetite particles which scientists believe form naturally within the brain. Possible air pollution link to Alzheimer's 2016-09-14T04:00:00Z Close to the center of the globules, she saw curious pancake shapes in which she found tiny grains of magnetite, plus grains formed by pyrite, made from iron and sulfur. We may have found life on Mars 24 years ago 2020-06-13T04:00:00Z "Oxidative cell damage is one of the hallmark features of Alzheimer's disease, and this is why the presence of magnetite is so potentially significant, because it is so bioreactive," she explained. Health Highlights: Sept. 6, 2016 2016-09-06T04:00:00Z But no one has identified the proposed sensory cells that contain magnetite. Humans—like other animals—may sense Earth's magnetic field 2019-03-18T04:00:00Z The particles appeared in a different shape than naturally occurring magnetite and were coupled to other similar metals. New Research Shows That Toxic Air Pollution Can Penetrate the Brain 2016-09-06T04:00:00Z About 25 years ago, geophysicist Joe Kirschvink at California Institute of Technology in Pasadena detected biologically formed magnetite particles in human brains, lending evidence to their natural origin. Industrial air pollution leaves magnetic waste in the brain 2016-09-05T04:00:00Z The concentration of the PAHs within the globules, the magnetite —produced when bacteria consume sulfur — and the presence of the microfossils suggested something stronger than unusual forms of carbon. We may have found life on Mars 24 years ago 2020-06-13T04:00:00Z Except in bacteria, however, no one has seen magnetite crystals serving as a magnetic sensor. The body’s hidden compass—what is it, and how does it work? 2016-06-23T04:00:00Z In 1978, he and Gould found magnetite in the abdomen of honey bees. Maverick scientist thinks he has discovered a magnetic sixth sense in humans 2016-06-23T04:00:00Z They discovered iron particles in the beaks of pigeons and hens, magnetite in the noses of trout, and other magnetic molecules in the ear hairs of birds. Why don’t birds get lost? They may have mastered quantum mechanics. 2016-06-09T04:00:00Z The problem with magnetite is that it’s toxic. Industrial air pollution leaves magnetic waste in the brain 2016-09-05T04:00:00Z Today, the remaining central argument — concerning the shape of the magnetite crystals — rests on whether they are biological or not. We may have found life on Mars 24 years ago 2020-06-13T04:00:00Z But longitude requires detecting subtle variations in field strength from place to place—an extra map or signpost sense that magnetite could supply, Lohmann says. The body’s hidden compass—what is it, and how does it work? 2016-06-23T04:00:00Z The needles, presumed to be made up of a strongly magnetic iron mineral called magnetite, would somehow open or close neural pathways. Maverick scientist thinks he has discovered a magnetic sixth sense in humans 2016-06-23T04:00:00Z They are mixing asphalt with ground iron ore that contains magnetite—an iron oxide which, as its name suggests, is magnetic. The hole story 2016-06-09T04:00:00Z As an expert in environmental magnetic particles, she knew that many, including magnetite, are prevalent in air pollution let off by power plant smokestacks. Industrial air pollution leaves magnetic waste in the brain 2016-09-05T04:00:00Z Nevertheless, Kathie Thomas-Keprta has reported that a quarter of the grains are the exact same size, shape, and structure as magnetite grains made by bacteria. We may have found life on Mars 24 years ago 2020-06-13T04:00:00Z And because there is no unique stain or marker for magnetite, false sightings are easy to make. The body’s hidden compass—what is it, and how does it work? 2016-06-23T04:00:00Z For many years, scientists thought chitons had evolved a way to synthesize magnetite simply because the hard mineral makes for a good, strong tooth. Maverick scientist thinks he has discovered a magnetic sixth sense in humans 2016-06-23T04:00:00Z At the conference, the magnetite and cryptochrome researchers made up distinct camps, each one quick to point out the opposing theory’s deficiencies. How Do Animals Keep from Getting Lost? 2016-05-28T04:00:00Z At 150 nanometers or less in diameter, these magnetite nanoparticles are small enough to be inhaled through the nose and enter the brain through the olfactory bulb, Maher explains. Industrial air pollution leaves magnetic waste in the brain 2016-09-05T04:00:00Z In 2000, she found six hundred magnetite crystals that looked identical to the ones produced by microbes. We may have found life on Mars 24 years ago 2020-06-13T04:00:00Z Scientists studying magnetoreception are zooming in on two possible mechanisms: a mechanical sensor based on the magnetic mineral magnetite and a biochemical sensor based on the protein cryptochrome. The body’s hidden compass—what is it, and how does it work? 2016-06-23T04:00:00Z I don’t always share the site’s editorial judgment, and I don’t know whether Nick Denton’s School for Gifted Youngsters can ever be the cultural magnetite it was in its early years. Former Gawker editors on the Hogan trial aftermath: 'It's about what journalists can cover' 2016-03-26T04:00:00Z In 1981, as a Ph.D. student at Princeton University, he proposed that magnetite, a naturally occurring oxide of iron that he had found in honeybees and homing pigeons, was the basis of the biocompass. How Do Animals Keep from Getting Lost? 2016-05-28T04:00:00Z And because unusually high concentrations of magnetite are found in the brains of people with Alzheimer’s disease, the findings raise the specter of an alarming new environmental risk factor for this and other neurodegenerative diseases. Industrial air pollution leaves magnetic waste in the brain 2016-09-05T04:00:00Z Some authorities believe the small magnetite crystals formed from the partial thermal decomposition of the host carbonate. We may have found life on Mars 24 years ago 2020-06-13T04:00:00Z As with magnetite, however, scientists haven’t yet seen the molecule in action and don’t know exactly how it might alter neural circuitry. The body’s hidden compass—what is it, and how does it work? 2016-06-23T04:00:00Z He and his colleagues propose adding tiny particles of magnetite, a form of iron oxide, to the cryoprotectant. Wait not in vain 2016-02-04T05:00:00Z Even a handful of magnetite crystals, he wrote at the time, could do the trick. How Do Animals Keep from Getting Lost? 2016-05-28T04:00:00Z The especially high levels of magnetite found in the study’s brain samples are shocking, he says, though not necessarily surprising given that they lived and worked in industrial environments with lots of air pollution. Industrial air pollution leaves magnetic waste in the brain 2016-09-05T04:00:00Z "From the perspective of the carbonate, the magnetite may have formed somewhere else." We may have found life on Mars 24 years ago 2020-06-13T04:00:00Z “The map sense could be magnetite, the compass sense could be radical pairs,” he says. The body’s hidden compass—what is it, and how does it work? 2016-06-23T04:00:00Z Put the organ in a rapidly fluctuating magnetic field and the magnetite will heat up fast. Wait not in vain 2016-02-04T05:00:00Z Yet studies suggest that magnetite plays no part in pigeon magnetoreception. Discovery of long-sought biological compass claimed 2015-11-15T05:00:00Z Still, he’s concerned that researchers found so much environmental magnetite in the brain. Industrial air pollution leaves magnetic waste in the brain 2016-09-05T04:00:00Z The magnetite crystals could have been "brought in from somewhere else, suspended in the ground water, and then were added to the carbonates as they crystallized," Thomas-Keprta says. We may have found life on Mars 24 years ago 2020-06-13T04:00:00Z Some researchers say it relies on an iron mineral, magnetite; others invoke a protein in the retina called cryptochrome. The body’s hidden compass—what is it, and how does it work? 2016-06-23T04:00:00Z "For magnetite this is 580C. When a mineral is heated to above its Curie temperature, it loses that information." 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 Such magnetite is more dangerous than biogenic versions of the particle, he says. Industrial air pollution leaves magnetic waste in the brain 2016-09-05T04:00:00Z 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 The trouble for producers like Gindalbie is they bet on the wrong ore: low-grade magnetite, which is more costly to produce than hematite, typically found at mines belonging to industry giants BHP Billiton Ltd. Iron Ore Got You Down? Try Nuclear Waste 2015-07-09T04:00:00Z The coal goes through a heavy media drum, where the medium of magnetite is added to make the water denser so the coal floats and the rock sinks. Anthracite still a vital part of Pennsylvania’s economy 2015-06-06T04:00:00Z Some clearly are; dust particles will include iron in the form of magnetite. Rosetta comet lander tells magnetic story 2015-04-14T04:00:00Z Using a variety of high-resolution imaging techniques, the researchers examined the characteristics of the brain samples’ magnetite. Industrial air pollution leaves magnetic waste in the brain 2016-09-05T04:00:00Z 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 The surprising colour is probably a signal that Ceres contains a lot of iron-rich minerals such as magnetite, says Andrew Rivkin, a planetary scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland. Spacecraft nears dwarf planet Ceres 2015-03-02T05:00:00Z Meanwhile a group at Stanford has reported that it can flip the electrical on/off switch in magnetite in one trillionth of a second—thousands of times faster than transistors now in use. How Supercomputers Will Yield a Golden Age of Materials Science 2013-11-25T13:15:00.723Z The firm began producing magnetite iron ore alongside copper at its Ernest Henry mine in Queensland two years ago. Glencore halts Australian iron ore 2013-07-16T08:27:32Z The researchers found biologically formed magnetite, too, but for every one of those particles, they found at least 100 pollution-derived magnetite particles, they report today in the Proceedings of the National Academy of Sciences. Industrial air pollution leaves magnetic waste in the brain 2016-09-05T04:00:00Z Hot fluids or ambient heat can reset an imprinted magnetic field if the temperature of magnetite rises to 585 degrees Celsius, its Curie point—the temperature at which magnetic fields are set in the mineral. Oldest rock crystals point to ancient magnetic shield for Earth 2015-07-30T04:00:00Z Instead, he found that the beak’s magnetite is mostly in macrophages. Birds’ magnetic sense: Columbarian Columbuses 2013-07-11T14:58:09Z An X-ray analysis by CheMin showed that the ground-up rock comprised mostly igneous minerals such as feldspar, pyroxene, olivine and magnetite. Mars Rover Finds Evidence of Ancient Habitability 2013-03-13T19:45:00.600Z Some of the rocks contained grains of iron called magnetite, and showed magnetic properties by deflecting a compass needle. Mysterious Shaman Stones Uncovered in Panama 2013-01-16T21:15:00.337Z Scientists think that the key to this ability is magnetite, the most magnetic of all minerals, which they've found embedded in bird and fish tissues. A Big Magnet in a Small Fish 2012-07-09T20:00:00Z Aim-listed African Minerals claims the world's biggest magnetite mining operation will earn the government $92bn in royalties over a decade or so. Sierra Leone fortunes change as diamond trade brings back investment 2012-06-10T14:51:14Z One is that the magnetic sensors are grains of magnetite, a form of iron oxide which, as its name suggests, is easily magnetised. Birds’ magnetic sense: Columbarian Columbuses 2013-07-11T14:58:09Z In fact, the only thing slowing the microbes down in the presence of magnetite was their own ability to grow. How Microbes Can Build Electric Grids 2012-06-04T20:45:00.197Z It’s a stumper; magnetite suspensions probably don’t need voting rights, but the creative tools, and their products, are getting ever smarter. Dutch Electronic Art Festival: Art In An Uncertain Europe 2012-05-28T15:34:17Z They tested the method in tissue isolated from the fish's noses, which contain magnetite. A Big Magnet in a Small Fish 2012-07-09T20:00:00Z The researchers took their inspiration from Magnetospirillum magneticum, a bacterium that is sensitive to the Earth’s magnetic field thanks to the presence within its cells of flecks of magnetite, a form of iron oxide. Nanotechnology: A fab result 2012-05-24T15:10:30Z In some cases the presence of minute garnets or magnetite assists in the cutting action. Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 6 "Home, Daniel" to "Hortensius, Quintus" 2012-03-15T02:00:32.250Z When the scientists examined the cells in the growing communities closely, they found nanoparticles of magnetite on the surface of cells and, in some cases, grains of the iron mineral connecting microbial pairs. How Microbes Can Build Electric Grids 2012-06-04T20:45:00.197Z Roman Kirschner’s Maelstrom employs a suspension of magnetite in liquid and magnetic force to create an endlessly shifting three-dimensional form. Dutch Electronic Art Festival: Art In An Uncertain Europe 2012-05-28T15:34:17Z In each isolated cell, the magnetite particles were next to the cell membranes, the scientists report online today in the Proceedings of the National Academy of Sciences. A Big Magnet in a Small Fish 2012-07-09T20:00:00Z At Arendal in Norway, the original locality for both the crystallized and botryoidal varieties, it is found in a bed of magnetite. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 9 "Dagupan" to "David" 2012-02-11T03:03:39.807Z African Minerals is developing a find at Tonkolili in the centre of the country that it says is the world's largest deposit of magnetite. Sierra Leone in uphill battle to avoid "resource curse" 2012-01-25T12:27:50Z After all, magnetite and other conducting minerals abound on Earth, and such metal-based grids, by allowing the long-distance transfer of electrons, would foster microbial growth. How Microbes Can Build Electric Grids 2012-06-04T20:45:00.197Z Spinel, magnetite and gold crystallize in simple octahedra. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 7 "Crocoite" to "Cuba" 2012-01-22T03:00:24.397Z Genetic analysis showed that the genes for producing magnetite and greigite appear to be in two separate groups or clusters on the genome. New Magnetic Bacteria! 2011-12-23T18:45:16.900Z It thus resembles magnetite in external characters, but is readily distinguished from this by the fact that it is only slightly magnetic. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 1 "Franciscans" to "French Language" 2011-10-22T02:00:29.487Z These sediments, however, are likely to contain traces of iron-bearing minerals like magnetite, which act like compasses. Q & A: How Do Scientists Accurately Date Stone Artifacts? 2011-09-12T21:20:05Z Among the accessory minerals may be mentioned apatite, magnetite, ilmenite, picotite and garnet. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 4 "G" to "Gaskell, Elizabeth" 2011-08-24T02:00:20.690Z Deposits of iron ore accumulated in the several ways referred to above may be metamorphosed and changed to hematite and magnetite. North America 2011-05-05T02:00:20.027Z Conversely, when the hydrogen sulfide concentration was artificially reduced, more magnetite crystals formed. New Magnetic Bacteria! 2011-12-23T18:45:16.900Z "It is the Snowden, in Victoria county; the ore is a fine grained magnetite; the mine is favorably situated, having a railway running into it." A Romance of Toronto A Novel 2011-04-23T02:00:04.677Z The open-cast mine - which will become fully operational later this year - promises to be the biggest magnetite iron ore mine in the world. Gold rush 2011-04-12T03:33:25Z The olivine is colourless in itself, but in most cases is altered to green or yellow serpentine, often with bands of dark magnetite granules along its cleavages and cracks. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 4 "G" to "Gaskell, Elizabeth" 2011-08-24T02:00:20.690Z Hematite shews a red streak when scratched with a knife, which distinguishes it from magnetite. Geology 2011-02-20T03:00:12.660Z One aspect of the Gindalbie project that especially alarms the region's farmers is that the mine is for magnetite iron ore, says Mills. Aussie Farmers, Chinese Miners Vie for Water 2011-02-10T16:00:00Z Under the microscope, it is seen to be a mechanical aggregate of corundum, usually in grains or minute crystals of a bluish colour, with magnetite, which also is granular and crystalline. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 3 "Electrostatics" to "Engis" 2011-02-06T03:00:53.093Z Demand for magnetite from Chinese steelmakers has increased as the nation’s refineries are geared to take the ore. Australia Wheat Suffers From Drought With Miners West of Flood 2011-02-02T13:07:10Z Many of these contain small quantities of chromium and nickel, and are associated with soapstone, potstone, dolomite, and magnetite. Asbestos Its production and use, with some account of the asbestos mines of Canada 2011-02-01T03:00:13.163Z Xstrata's offer for Sphere, a move to expand its iron ore holdings with Sphere's magnetite iron ore deposits in Mauritania, is due to expire on October 19. Singapore firm to counter Xstrata's Sphere bid: report 2010-10-04T04:29:00Z Sinosteel, China's biggest iron ore trader, is also developing a magnetite project in the Mid West part of the state. Aussie Farmers, Chinese Miners Vie for Water 2011-02-10T16:00:00Z Other iron oxides, like haematite and limonite, may be present as alteration-products of the magnetite. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 3 "Electrostatics" to "Engis" 2011-02-06T03:00:53.093Z “Processing these magnetite ores is going to be pretty greedy for water.” Australia Wheat Suffers From Drought With Miners West of Flood 2011-02-02T13:07:10Z The essential peculiarity of the veins at Thetford is that they are occasionally associated, as already mentioned, with grains and threads of chromic iron and also of magnetite. Asbestos Its production and use, with some account of the asbestos mines of Canada 2011-02-01T03:00:13.163Z Here are the best of our web users' solutions: Attach a series of powerful, fixed magnets to the pipework a short way back on the live side of the leak, then inject magnetite. Your suggestions: how to stop the oil leak 2010-06-03T07:49:00Z "Processing these magnetite ores is going to be pretty greedy for water." Aussie Farmers, Chinese Miners Vie for Water 2011-02-10T16:00:00Z The Rochester team has developed techniques for studying tiny magnetite minerals trapped inside the crystals of volcanic rock. Rocks record early magnetic field 2010-05-04T09:19:00Z It occurs in veins in slaty rocks, associated with jaspers and quartzites rich in magnetite and brown iron-ore. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 7 "Arundel, Thomas" to "Athens" The Archean of the Vermilion district of Minnesota comprises the Soudan formation, an altered sedimentary series with banded cherts, jasper and magnetite schists; the iron ores are extensively mined. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 4 "Aram, Eugene" to "Arcueil" The magnetite would eventually form a solid plug within the bore of the pipework. Your suggestions: how to stop the oil leak 2010-06-03T07:49:00Z Other minerals, except apatite, zircon and magnetite, are typically absent. Encyclopaedia Britannica, 11th Edition, Volume 4, Slice 3 "Borgia, Lucrezia" to "Bradford, John" It must not be inferred, that, because the mineral is called magnetite, all specimens possess the property called magnetism. The Telephone An Account of the Phenomena of Electricity, Magnetism, and Sound, as Involved in Its Action It exists as small specks in the centre of grains of magnetite. The Galaxy, April, 1877 Vol. XXIII.—April, 1877.—No. 4. 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" In contact with steam at a red heat it forms magnetite and ammonia. Etna A History of the Mountain and of its Eruptions Basalt is the most fusible of volcanic rocks, owing to the augite and magnetite it contains, so that it spreads out with a very slight slope when highly fused. Volcanoes: Past and Present The magnetite crystals of these deposits interpenetrate with the other constituents of an igneous rock, commonly of a gabbro type, and the deposits themselves are essentially igneous rocks. The Economic Aspect of Geology Most of the ores obtained in Pennsylvania and New York are magnetite. Commercial Geography A Book for High Schools, Commercial Courses, and Business Colleges 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 ground mass was found to consist of felspar microliths, and grains of olivine, augite, and magnetite, with some interstitial glass. Etna A History of the Mountain and of its Eruptions Melaphyre is a name given to the very dark varieties of altered augitic lavas, rich in magnetite and chlorite. Volcanoes: Past and Present Emery is an intimate mechanical mixture of corundum, magnetite, and sometimes spinel. The Economic Aspect of Geology Many of the latter are magnetite, while the others are hornblende and various ferromagnesian silicates. Aboriginal Remains in Verde Valley, Arizona Thirteenth Annual Report of the Bureau of Ethnology to the Secretary of the Smithsonian Institution, 1891-92, Government Printing Office, Washington, 1896, pages 179-262 In the red and brown iron ores and ochres ferric iron is present; in chalybite the iron is in the ferrous state; and in magnetite it is present in both forms. A Text-book of Assaying: For the Use of Those Connected with Mines. In addition, the rock is filled with minute crystals of octahedral form which are composed of magnetite, and scattered through the rock are minute yellow crystals of rutile. Illustrated Catalogue Of The Collections Obtained From The Indians Of New Mexico And Arizona In 1879 Second Annual Report of the Bureau of Ethnology to the Secretary of the Smithsonian Institution, 1880-81, Government Printing Office, Washington, 1883, pages 307-428 Vesuvian lava, glass paste with numerous crystals of leucite; others of augite and nepheline porphyritically developed; also small grains of magnetite. Volcanoes: Past and Present Certain minerals, such as magnetite, ilmenite, spinel, corundum, etc., are often found as primary segregations within the mass of igneous rock. The Economic Aspect of Geology The gravels below a promising region of limestones rich in garnets were washed for gold, but only magnetite was found. South with Scott It chiefly occurs as oxide, as in magnetite, hæmatite, and in the brown iron ores and ochres. A Text-book of Assaying: For the Use of Those Connected with Mines. The magnetite is a conductor of electricity which is easily vaporized. Artificial Light Its Influence upon Civilization Group of leucite crystals of irregular form from the lava of 1855, congregated around a nucleus of crystals of plagioclase and magnetite. Volcanoes: Past and Present About five per cent of the world's production of iron ore is from bodies of magnetite formed in association with igneous rocks. The Economic Aspect of Geology Sections of the finer schist in polarized light show many small areas of quartz and plagioclase and numerous crystals of epidote, magnetite, and chlorite, the whole having a marked parallel arrangement. History and Comprehensive Description of Loudoun County, Virginia Chalybite and the hydrated oxides dissolve very readily in hydrochloric acid; hæmatite and magnetite dissolve with rather more difficulty. A Text-book of Assaying: For the Use of Those Connected with Mines. The magnetite or luminous arc-lamp next appeared and met with considerable success. Artificial Light Its Influence upon Civilization Gabbro, from Carlingford Hill, Ireland, consisting of anorthite, augite, a little olivine, and magnetite. Volcanoes: Past and Present Here the magnetite forms a great tabular vertical body lying between porphyry and syenite. The Economic Aspect of Geology The process in detail consists in freeing the bath of melted pig-iron from excess of carbon by adding broken lumps of pure hematite or magnetite iron ore. Heroes of the Telegraph I felt certain that there must be large bodies of magnetite in the East, which if crushed and concentrated would satisfy the wants of the Eastern furnaces for steel-making. Edison, His Life and Inventions There is some sericite present, also magnetite, resulting from the decomposition of the biotite. The Long Labrador Trail "Now," I said, forgetting my dignity under the enthusiasm with which I was inspired by my visitor's words, and infected more or less with his undoubtedly magnetite spirit—"now you're shouting." The Water Ghost and Others Crystalline magnetite and hematite are more resistant to erosion than almost any other type of rock, and stand out at the surface with proportional frequency. The Economic Aspect of Geology This young scientist, too, cherished loving thoughts about Angelina, thoughts of a more earthly and volcanic tinge; certain definite projects which made him forget, at times, his preoccupation with biotite, perlite, magnetite, anorthite, and pyroxene. South Wind A compact rock of light red color, made up of uniformly rounded grains of quartz, and the feldspar with occasional grain of magnetite. The Long Labrador Trail A soft extremely fine grained gray rock, with a well developed schistose structure, carrying much magnetite, plagioclase, orthoclase and their alteration products. The Long Labrador Trail A coarse dark green rock whose principal constituents are pyroxene plagioclase and magnetite. The Long Labrador Trail The minerals at contact are quartz, biotite, magnetite and hornblende. The Long Labrador Trail A coarse black rock carrying magnetite and pyrites in considerable quantities. The Long Labrador Trail The grains of the constituent minerals, quartz, feldspar and magnetite have an angular brecciated appearance; showing uneven extinction and strong crushing effects. The Long Labrador Trail The magnetite is somewhat decomposed, the resulting hematite filling the spaces between the quartz grains. The Long Labrador Trail It is also somewhat stained by the decomposition of the magnetite. The Long Labrador Trail |
| 随便看 |
英语例句辞典收录了117811条英语例句在线翻译词条，基本涵盖了全部常用单词及词组的例句翻译及用法，是英语学习的有利工具。