Tag Archives: diamond

New mineral that shouldn’t exist at Earth’s surface found trapped in a diamond

Scientists found a mineral that was never encountered before in nature trapped in the dark inclusions of this diamond. Credit: Aaron Celestian / Los Angeles County Natural History Museum.

The most prized diamonds aren’t the largest, rather the purest. But one man’s trash is another man’s treasure. An impurity inside an inconspicuous diamond unearthed from an African mine in the 1980s turned out to be a new type of mineral previously unknown to science. This isn’t just any kind of mineral, either. It’s the only mineral formed in the planet’s lower mantle that we’ve ever found, and could thus greatly improve our understanding of Earth’s interior and how it formed.

The mineral in question, christened davemaoite after pioneering geophysicist Ho-kwang “Dave” Mao who studied how materials react to extreme pressure, was found in dark inclusions inside a diamond mined from Botswana. In 1987 it was sold by a gem dealer and changed hands until it reached the trained eye of geologists at the University of Nevada, Las Vegas.

“For jewelers and buyers, the size, color, and clarity of a diamond all matter. Inclusions — those black specks that annoy the jeweler — for us, they’re a gift,” said mineralogist Oliver Tschauner of the University of Nevada, Las Vegas. “I think we were very surprised. We didn’t expect this.” 

The calcium silicate compound was surprising because we should never have been supposed to find it. The mineral formed hundreds of miles beneath Earth’s surface, inside the lower mantle between the core and the crust where temperature and pressure are ungodly high. Davemaoite’s structure is supposed to collapse outside the high-pressure environment of the mantle but since it was trapped in a diamond, the toughest material known to man, the mineral survived.

So what looked like a dark blemish turned out to be one of the rarest finds a geologist can ever hope to discover. And since davemaoite can host uranium and thorium, radioactive elements that are responsible for heating up Earth’s lower mantle, scientists believe that the newly discovered mineral can help answer some questions about Earth’s interior, with wide ramifications. For instance, the movements inside the planet’s lowest layers is believed to at least partially drive plate tectonics.

Davemaoite is only the second high-pressure mantle silicate ever seen on Earth’s surface. The other, named after Nobel laureate Percy Bridgman, was found inside a meteorite.

“The two form an exclusive club as the only lower-mantle silicate minerals confirmed in nature,” said co-author Yingwei Fei of Carnegie Science.

Now that scientists know what’s possible, they’ll be on the lookout for other lower mantle minerals that could have existed under our noses for all this time.

“The discovery of davemaoite inspires hope for finding other difficult high-pressure mineral phases in nature,” Fei said. “Being able to obtain more direct samples from the inaccessible lower mantle would fill in our knowledge gap regarding the chemical composition and variability of our planet’s depths.”

Davemaoite has been officially added by the International Mineralogical Association to its list of known minerals. The findings appeared in the journal Science.

Strongest glass in the world can scratch diamonds

A piece of 1mm-wide AM-III glass left scratch marks on the surface of a natural diamond. Photo: National Science Review

Glass is associated with brittleness and fragility rather than strength. However, researchers in China were able to create a new transparent amorphous material that is so strong and hard that it can scratch diamonds. What’s more, this high-tech glass has a semiconductor bandgap, which makes it appealing for solar panels.

Strongest amorphous material in the world

Diamond, the hardest material known to date in the universe, is often used in tools for cutting glass. But the tables have turned.

“Comprehensive mechanical tests demonstrate that the synthesized AM-III carbon is the hardest and strongest amorphous material known so far, which can scratch diamond crystal and approach its strength. The produced AM carbon materials combine outstanding mechanical and electronic properties, and may potentially be used in photovoltaic applications that require ultrahigh strength and wear resistance,” the authors of the new study wrote.

The new material developed by scientists at Yanshan University in Hebei province, China, is tentatively named AM-III and was rated at 113 gigapascals (GPA) in the Vickers hardness test. Vickers hardness, a measure of the hardness of a material, is calculated from the size of an impression produced under load by a pyramid-shaped diamond indenter.

That’s more than many natural diamonds that have a Vickers score in the range of 70-100 GPa, but less than the hardest diamonds that can score up to 150 GPa.

It’s about ten times harder than mild steel and could be 20 to 100 times tougher than most bulletproof windows.

Shaped like diamonds, looks like glass

Like diamonds, AM-III is mostly made of carbon. But while carbon atoms in diamond are arranged in an orderly crystal lattice, glass has a chaotic internal structure typical of an amorphous material. This is why glass is typically weak, but AM-III has micro-structures in the material that appear orderly, just like crystals. So, AM-III is part glass, part crystal, which explains its strength.

In order to make AM-III, the Chinese researchers had to employ a process that is even more complicated than manufacturing artificial diamonds. The most common method for creating synthetic diamonds used in the industry is called high pressure, high temperature (HPHT). During HPHT, carbon is subjected to similarly high temperatures and pressure as those that led to the formation of natural diamonds deep in the Earth, around 1,300 degrees Celsius (1650 to 2370 degrees Fahrenheit) and a pressure 50,000 times greater on the surface.

Instead of graphite, the raw material of artificial diamonds, the Chinese researchers started off with fullerene, also called buckminsterfullerene. These molecules contain at least 60 atoms of carbon, commonly denoted as C60, arranged in a lattice that can either form a ball or sphere shape and are typically 1nm diameter.

These carbon “footballs” are typically soft and squishy. But after being subjected to great heat and pressure, the carbon balls are crushed and blended together.

The fullerene was subjected to about 25 GPa of pressure and 1,200 degrees Celsius (2,192 degrees Fahrenheit). However, the researchers were careful to reach these conditions very gradually, taking their time over the course of about 12 hours. Immediately subjecting the material to high pressure and heat may have turned the carbon balls into diamonds.

The resulting transparent material is not only hard but also a semiconductor, with a bandgap range almost as effective as silicon, the main semiconductor used in electronics. So besides bulletproof glass, it could prove useful in the solar panel industry where its properties can shine by allowing sunlight to reach photovoltaic cells, while also enhancing the lifespan of the product.

AM-III was described in a recent study published in the journal National Science Review

Diamond battery powered by nuclear waste runs for 28,000 years

The radioactive diamond battery. Credit: NDB.

A U.S. startup combined radioactive isotopes from nuclear waste with ultra-slim layers of nanodiamonds to assemble a ridiculous battery that allegedly can last 28,000 years.

According to the California startup in question, called NDB (Nano Diamond Battery), their product is a “high-power diamond-based alpha, beta, and neutron voltaic battery.”

Diamond batteries are forever

The energy comes from waste graphite that was previously used in graphite-cooled nuclear reactors. The radioactive graphite is encased in layers of nano-thin, single crystalline diamond, which act both as a semiconductor and heat sink.

Diamond is the hardest material known to man. It also has the highest energy-conductivity, meaning it quickly transfers heat from the radioactive graphite. So the diamond layers not only collect charge, but also prevent radiation leakage.

Since the carbon-14 isotopes have half-life times in the range of thousands of years and diamonds are virtually indestructible, NDB felt confident making this bombastic marketing claim.  

“This battery has two different merits,” NDB CEO and co-founder Nima Golsharifi said in an interview with Future Net Zero. “One is that it uses nuclear waste and converts it into something good. And the second is that it runs for a much longer time than the current batteries.”

The product is supposed to come in two versions. The “forever” version that is supposed to last 28,000 years before it runs out of charge. This hard-core version is meant for niche applications, such as deep space where it could power instruments onboard spacecraft and satellites. These spacecraft, for instance, could be sent to other star systems on centuries-long voyages and they would still have enough power to beam back messages.

There is also a consumer version, meant for powering electric vehicles, smartphones, and other small devices. Since the graphite would be wrapped in multiple coatings of synthetic diamond, there would be no radiation leaking out of your phone. NDB even claims that the radiation levels emitted by the cells will be less than those emitted by the human body.

“Think of it in an iPhone. With the same size battery, it would charge your battery from zero to full, five times an hour. Imagine that. Imagine a world where you wouldn’t have to charge your battery at all for the day. Now imagine for the week, for the month… How about for decades? That’s what we’re able to do with this technology,” NDB’s Neel Naicker said in a statement.

That may or may not be true, but frankly, it would be interesting to see who would buy a product fully aware that it contains a radioactive battery.

The charge collected by battery cells is collected, stored, and instantly distributed by a supercapacitor. Cells can be built to conform to any shape or standard, including AA, AAA, 18650, 2170, or all manner of custom sizes.

For now, NDB has only completed a proof of concept. The company was about to release a commercial prototype, but then came COVID. Nevertheless, the company expects to release a low-power commercial version of its radioactive diamond battery in less than two years, while the high-power version is slated for five years’ time. 

Canadian diamonds give researchers a glimpse into ancient continents

A chance discovery by diamond-prospecting geologists provides a glimpse into the Earth’s past.

Diamond embedded in a piece of kimberlite.
Image credits James St. John / Flickr

Diamond exploration samples from Baffin Island, Canada point to a never-before-seen part of the North Atlantic craton—an ancient part of Earth’s continental crust that stretches from Scotland to Labrador. The finding will allow researchers to better map the lost continents of Earth’s distant past.

A diamond in you

“For researchers, kimberlites are subterranean rockets that pick up passengers on their way to the surface,” explains University of British Columbia geologist Maya Kopylova. “The passengers are solid chunks of wall rocks that carry a wealth of details on conditions far beneath the surface of our planet over time.”

Kimberlite rocks form very, very deep in the Earth’s crust — similarly to diamonds — and are thus a staple of diamond prospectors around the world. After forming for millions of years at depths of between 150 to 400 kilometers, these rocks are sometimes pushed up to the surface by various geological processes, snatching diamonds along for the ride.

Kopylova and colleagues were analyzing samples from De Beers’ Kimberlite Province Chidliak in southern Baffin Island, when they noticed that the samples were peculiar. Their mineral makeup matched that in other portions of the North Atlantic craton, which is “so unique there was no mistaking it”. The mineral compositions of adjacent ancient cratons have “completely different mineralogies,” Kopylova explains.

Cratons are pieces of continents billions of years old that have remained stable over time and act as the kernel of today’s continents — think of them as anchors that today’s landmasses hold on to. Most cratons have been broken up and moved around by tectonics over time, but some still form the bedrock of modern tectonic plates like the North American plate. Knowing where the pieces of these cratons are today allows researchers to understand how they evolved and moved over time, in essence allowing them to map the evolution of our planet’s surface.

“Finding these ‘lost’ pieces is like finding a missing piece of a puzzle,” says Kopylova. “The scientific puzzle of the ancient Earth can’t be complete without all of the pieces.”

To the best of our knowledge so far, the continental plate of the North Atlantic craton broke apart some 150 million years ago, and the fragments spread from northern Scotland to southern Greenland and Labrador. the newly-discovered fragments would increase its known expanse by roughly 10%.

“With these samples we’re able to reconstruct the shapes of ancient continents based on deeper, mantle rocks,” says Kopylova. “We can now understand and map not only the uppermost skinny layer of Earth that makes up one percent of the planet’s volume, but our knowledge is literally and symbolically deeper.”

“We can put together 200-kilometer deep fragments and contrast them based on the details of the deep mineralogy.”

The paper “The metasomatized mantle beneath the North Atlantic Craton: Insights from peridotite xenoliths of the Chidliak kimberlite province (NE Canada)” has been published in the Journal of Petrology.

Researchers devise fast, relatively cheap way of building diamonds

The process of making one such faux diamond starts with a handful of white dust that gets compressed in a diamond-lined pressure chamber, then shot with a laser. The combination of extreme pressure and heat turns the raw material into pure diamond — just like Mother Nature makes them.

Raw diamond.
Image credits Robert Matthew Lavinsky.

The process of making one such faux diamond starts with a handful of white dust that gets compressed in a diamond-lined pressure chamber, then shot at with a laser. The combination of extreme pressure and heat turns the raw material into pure diamond — just like Mother Nature makes them.

Diamonds on the cheap

“What’s exciting about this paper is it shows a way of cheating the thermodynamics of what’s typically required for diamond formation,” said Rodney Ewing, Stanford geologist and co-author of the paper.

The process described by the team uses heat and pressure to turn hydrogen and carbon molecules derived from crude oil and natural gas into literal diamonds. It’s not the first process to try and produce the gem, and indeed not even the first successful one at that — but it is currently the cheapest, most efficient one that produces the highest-quality diamonds.

“We wanted to see just a clean system, in which a single substance transforms into pure diamond — without a catalyst,” Sulgiye Park, the study’s lead author and postdoctoral research fellow at Stanford’s School of Earth, Energy & Environmental Sciences (Stanford Earth) told phys.org.

Natural diamonds form hundreds of kilometers beneath the surface from carbon. The ones we can reach and mine out of the ground were moved there, after formation, through ancient volcanic eruptions. The ones the team produces start as a mixture of three powders derived from petroleum and natural gas. These are particles of carbon atoms arranged in the same structure as in a diamond.

Image via Wikimedia.

Diamonds immediately make us think of jewelry, but they do have a lot of other cool uses as well. They’re extremely stable chemically, have nice optical properties, very high heat conductivity, and they are the hardest material we’ve found on this good Earth. Industries ranging from metal processing to medicine rely on diamonds for specialized applications. The team hopes that their process will help make diamonds more accessible and more customizable for such applications.

The paper “Facile diamond synthesis from lower diamondoids” has been published in the journal Science Advances.

Deep diamonds hint at Earth’s primordial magma

A vast reservoir of magma lies undisturbed for billions of years. Researchers have seen signs of it in some superdeep diamonds.

Super-deep diamonds could help us learn more about unperturbed magma pockets. (Graham Pearson)

Our planet’s general structure is fairly simple: there’s a core, a mantle, and a crust. But the more you zoom in, the more complex things start to get. The crust, the thinnest layer of our planet, is immensely complicated and we’ve only managed to dig through to 13 km deep — with the average thickness of continental crust being around 35 km. The mantle is strongly influenced by convection currents. Some of it slowly creeps towards the surface, carrying heat and material from the planet’s interior to the surface — while in other places, the mantle absorbs portions of the crust. As for the core, almost everything we know about it comes from indirect information, and it’s remarkable that we know anything about it at all.

Not all the mantle might be engaged in such motion, however. Geologists have long suspected that there are pockets of magma that haven’t been moved in our planet’s constant churning.

The theory first came to life when researchers analyzed the ratio of two helium isotopes (helium 3 and helium 4) in some volcanic eruptions. The ratio was surprisingly similar to that of extremely old meteorites that crashed on Earth, hinting that the magma that flew in the volcanic eruptions was also extremely old.

“This pattern has been observed in ‘Ocean Island Basalts’, which are lavas coming to the surface from deep in the Earth, and form islands such as Hawaii and Iceland” said research leader Dr. Suzette Timmerman, from the Australian National University. “The problem is that although these basalts are brought to the surface, we only see a glimpse of their history. We don’t know much about the mantle where their melts came from”.

Diamonds, however, are extremely sturdy, and they can preserve inclusions much older than themselves.

Most diamonds form around 150-220 km below the planet’s surface, and are carried towards the surface. However, some diamonds can form up to 800 km deep, and these super-deep diamonds are quite different from normal ones. Timmerman explains:

“Diamonds are the hardest, most indestructible natural substance known, so they form a perfect time capsule that provides us a window into the deep Earth.”

“We were able to extract helium gas from twenty-three super-deep diamonds from the Juina area of Brazil. These showed the characteristic isotopic composition that we would expect from a very ancient reservoir, confirming that the gases are remnants of a time at or even before the Moon and Earth collided. From the geochemistry of the diamonds, we know that they formed in an area called the ‘transition zone’, which is between 410 and 660 km below the surface of the Earth. This means that this unseen reservoir, left over from the Earth’s beginnings, must be in this area or below it.”

Inclusions in microscopic cavities in the superdeep diamonds, like those shown in these electron microscope images, indicate the presence of primordial magma deep within the mantle. Image credits: Suzette Timmerman.

When the team analyzed the helium 3 to helium 4 ratio, they found the same ratio as in the old meteorites. Although the diamonds are “only” 500 million years old themselves, they were formed in a pocket of primordial magma, encapsulating some of the ancient helium 3 as it slowly diffused away.

This means that the diamonds were formed in such a pocket of unmoved magma, but we still don’t know where exactly this reservoir is and whether there is one big reservoir or multiple ones scattered across the globe. The composition of this reservoir is also unclear, but it is presumably quite dense, since it doesn’t seem to mix with the rest of the mantle, even after billions of years.

However, we now have confirmation that there is some material on Earth that has remained unmoved since the dawn of our planet, for some 4.5 billion years — and that’s pretty awesome.

The study has been published in Science.

Travels in Geology — Arkansas: A geologic diamond in the rough

The right geological conditions resulted in the presence of diamonds in Arkansas — and this historical diamond deposit is open to the public for collecting.

Crater of Diamonds State Park.


Mine your own diamonds

North America is not a continent known for its wealth of gemstones — while there are hundreds of rich gold and metal deposits, fine gems were difficult for explorers and prospectors to find. Crater of Diamonds State Park is the location of one of only two diamond pipes in the United States and the only diamond mine in the world where the public is welcomed to try their hand at mining diamonds. The right set of geological conditions allowed for the presence of diamonds and a history of mining attempts eventually led to the park as we see it today.

Geological History of the Crater of Diamonds

Diamonds form deep in the Earth’s crust and upper mantle, over 60-100 miles deep. Volcanic and tectonic events can bring diamonds closer to the surface, but the right conditions must be met in order for the diamonds to not be destroyed in the process. This is the case here: roughly 100 million years ago, a volcanic vent exploded in Arkansas, bringing mantle rock towards the surface

That volcanic vent formed an 83-acre crater and is known as the Prairie Creek Diatreme. The rapid rise of material from the mantle allowed diamonds to be brought up to the surface without being carbonized or otherwise destroyed. A hundred million years of erosion reduced the profile of the crater and resulted in the landscape of the area today.

Mining History at the Crater

Diamonds were first discovered at the crater in August 1906 by landowner and farmer John Wesley Huddleston. What followed was a short-lived diamond rush and Huddleston sold his land to investors who would form the Arkansas Diamond Company. Neighboring Huddleston’s land, a portion of diamond-bearing land was owned by M. Mauney who sold three-quarters of the land to Horace Bemis, who formed the Ozark Diamond Corporation. Bemis’ land was eventually sold to a father and son team named the Millars who built a diamond processing plant.

The diamond processing plant was quite successful until it was destroyed in an unsolved arson in 1919. After many decades of failed mining attempts in the area, competing public diamond collecting tourist attractions were opened under the names ‘The Crater of Diamonds’ and ‘The Big Mine’. In 1969 a corporation bought both diamond-bearing properties and continued operating the diamonds fields as a tourist attraction. The state of Arkansas bought the lands in 1972 to form the Crater of Diamonds State Park.

Crater of Diamonds State Park

The Crater of Diamonds State Park is the only diamond mine where visitors are allowed to try to find diamonds and keep them. The park is open year-round aside from Christmas, Thanksgiving, and New Years and visitors pay an entry fee and can rent equipment for use in the search for diamonds.

Visitors can also bring their own equipment but are not allowed to use tools that have batteries, motors, or wheels. Park workers will help identify and document all diamonds that are found. Most of the diamonds that are found tend to be less than 1 carat in size (a reference chart can be printed here), but large diamonds do occur; such as the 16.37 carat Amarillo diamond found in 1972.

The Right History to Make a Diamond Park

The right set of geological conditions helped to bring diamond deposits to a continent that is lacking in gemstones. The many mining failures in the early 1900’s led to the formation of public diamond-collecting tourist attractions rather than commercial mines. The Crater of Diamonds State Park today allows the public to come and try finding diamonds for themselves.

There may be a quadrillion tons of diamond in the Earth’s depths — but we’ll never mine it

Researchers have discovered what appears to be a cache of diamonds hidden in the Earth’s mantle. This suggests that, at a geological scale, diamond might not be the exotic mineral we once thought it to be — they may be quite common, though not easily accessible.

Diamond embedded in a rock matrix. Image credits: Rob Lavinsky.

Earthquakes and diamonds

The world’s deepest borehole goes down 12.262 kilometers (40,230 ft). How is it then that we know so much about the depths of the Earth, which boasts an average radius of over 6,300 km? As is so often the case, scientists have gathered a trove of data which enabled them to infer many things beyond sight — in this case, of the Earth’s interior properties.

Most of this data comes from seismic waves — which are essentially subsurface acoustic waves. Every time an earthquake (or a large enough explosion) takes place, it sends out seismic waves which can be picked up by seismic stations across the world. According to the U.S. Geological Survey’s National Earthquake Information Center, there are over 3000 seismic stations currently operating across the world.

Seismometers record the ground movement on a seismograph. Based on the wiggles of the seismograph, certain pieces of information can be drawn, particularly about the nature of the ground the wave has passed through. Of course, this is a great simplification and the seismogram analysis process is much more intricate, often involving a great deal of complexity and mathematical algorithms. You can pick up simpler things, like where the earthquake epicenter was and how much energy the earthquake had, or use the data for complex things — like constructing an image of what the Earth’s interior might look like.

A simplified “slice” of the Earth, showing its major components (not to scale). Image credits: Siyavula Education.

For decades, agencies such as the USGS, universities, and research groups have been keeping track of this seismic activity. Among many other things, scientists have noticed an intriguing anomaly: the velocity of some seismic waves in some areas could not be explained with our existing knowledge of the Earth’s structure.

In this particular case, an MIT team aimed to identify the composition of so-called cratonic roots that might explain the spikes in seismic speeds. They concluded that the reason for this anomaly is diamonds.

“This shows that diamond is not perhaps this exotic mineral, but on the [geological] scale of things, it’s relatively common,” says Ulrich Faul, a research scientist in MIT’s Department of Earth, Atmospheric, and Planetary Sciences. “We can’t get at them, but still, there is much more diamond there than we have ever thought before.”

Cratons

Cratons whose ancient rocks are widely exposed at the surface are typically called shields. If the ancient rocks are largely overlain by a cover of younger rocks, the craton is generally referred to as a platform. Image credits: USGS.

The Earth’s crust made out of mobile, dynamic tectonic plates. We don’t see that because the movement is essentially unnoticeable at a human scale, but at a geological scale, tectonic plates move about quite a lot. Most tectonic plates’ movement is on the scale of a few centimeters per year.

Cratons are very old and stable parts of the Earth’s tectonic crust. Most cratons on Earth have survived cycles of merging and rifting of continents, and are typically located at the interior of tectonic plates. They have a thick crust and deep lithospheric “roots” that can extend several hundred kilometers into the Earth’s mantle.

Cratons are also colder and less dense than the surrounding mantle, which means that they would yield slightly faster seismic waves — but this alone can’t entirely account for the speed anomaly. So there must be something else.

“The velocities that are measured are faster than what we think we can reproduce with reasonable assumptions about what is there,” Faul says. “Then we have to say, ‘There is a problem.’ That’s how this project started.”

In order to solve this conundrum, Faul and colleagues started assembling virtual rocks which could theoretically exist at the temperature and pressure conditions in those parts of the mantle. They then calculated how fast seismic waves would pass through these structures, to see if this would fit the observed seismic data.

They found that the data would be best explained by a craton rock composition of 1 to 2 percent diamond. This would translate to about quadrillion tons of diamond.

In a way, this makes a lot of sense. We know that diamonds are forged deep in the bowels of the Earth, in high-pressure, high-temperature environments. The only reason why we’re able to find diamonds is that they’re brought closer to the surface by volcanic eruptions which act like “pipes” — bringing them to the surface, where we at least have a chance of finding them.

Of course, it’s important to note that Faul and colleagues found no direct evidence that the craton roots do contain diamonds, it’s just that this explanation seems to fit best. But this line of thinking has brought us so far, so at least for now, it seems convincing enough.

“It’s circumstantial evidence, but we’ve pieced it all together,” Faul says. “We went through all the different possibilities, from every angle, and this is the only one that’s left as a reasonable explanation.”

Journal Reference: Joshua M. Garber et al. Multidisciplinary “Constraints on the Abundance of Diamond and Eclogite in the Cratonic Lithosphere”, Geochemistry, Geophysics, Geosystems (2018). DOI: 10.1029/2018GC007534.

This diamond contains the first evidence of calcium silicate perovskite found in nature. Credit: Nester Korolev, UBC.

Tiny diamond provides first evidence of Earth’s fourth most abundant mineral

This diamond contains the first evidence of calcium silicate perovskite found in nature. Credit: Nester Korolev, UBC.

This diamond contains the first evidence of calcium silicate perovskite found in nature. Credit: Nester Korolev, UBC.

Calcium silicate perovskite (CaSiO3) is widely regarded as the fourth most abundant mineral on Earth but it was only recently that people were able to actually see it intact. That’s because the mineral is thought to form deep inside Earth’s mantle, an area below the planet’s surface, but above the planet’s core. Only after it made its way to the surface, trapped inside a diamond recovered from a South African mine, did we get confirmation that this mineral even exists in a stable form. As such, it provides valuable insight into the processes that govern Earth’s interior.

First time found in nature

“Nobody has ever managed to keep this mineral stable at the Earth’s surface,” said Graham Pearson, a professor in the University of Alberta’s Department of Earth and Atmospheric Sciences, in a statement.

“The only possible way of preserving this mineral at the Earth’s surface is when it’s trapped in an unyielding container like a diamond,” he explained. “Based on our findings, there could be as much as zetta tonnes (1021) of this perovskite in deep Earth.”

The lucky diamond was excavated from South Africa’s Cullinan mine, where incidentally the world’s largest diamond was also found back in 1905. This goes to show that Cullinan is not only a source for material riches but also scientifically valuable, as it provides insights into Earth’s deep core.

“Being the dominant host for calcium and, owing to its accommodating crystal structure, the major sink for heat-producing elements (potassium, uranium and thorium) in the transition zone and lower mantle, it is critical to establish its presence,” the authors wrote in the journal Nature. 

Most diamonds form 150 to 200 km below Earth’s surface, but Pearson says the perovskite-containing diamond likely formed some 700 km (435 miles) deep. The scientist thinks the diamond must have sustained 24 billion pascals of pressure — or 240,000 more than the average at sea level.

This important discovery once again highlights diamonds’ important role in preserving material and revealing clues about some of the most mysterious geological processes. The calcium silicate perovskite inclusion — perhaps the first intact sample of this material that we know of — was confirmed with X-ray and spectroscopy tests.

“Diamonds are really unique ways of seeing what’s in the Earth,” Pearson said. “And the specific composition of the perovskite inclusion in this particular diamond very clearly indicates the recycling of oceanic crust into Earth’s lower mantle. It provides fundamental proof of what happens to the fate of oceanic plates as they descend into the depths of the Earth.”

Previously, in 2014, Pearson was behind another milestone discovery which found the first evidence of ringwoodite — Earth’s fifth most abundant mineral — in another diamond.

Scientific reference: F. Nestola et al, CaSiO3 perovskite in diamond indicates the recycling of oceanic crust into the lower mantle, Nature (2018). DOI: 10.1038/nature25972.

Unexpected deep-Earth oxidized iron surprises geologists

Researchers drilling into the Earth’s mantle have made an unexpected finding: analyzing rocks which came from 550 km below the surface, they discovered highly oxidized iron, similar to the rust we see on our planet’s surface.

Diamonds with garnet inclusions can form at depths down to 550 kilometers below the surface. Image credits: Jeff W. Harris, University of Glasgow.

If there’s something you don’t expect to find kilometers beneath the surface, it’s rust. The oxidized iron was found as inclusions in diamonds and garnets coming from the deep mantle. Of course, researchers didn’t drill 550 km (the deepest borehole “only” went 12 km deep) but reaching the top of the mantle enables geoscientists to analyze rock samples that migrated from deeper parts.

It’s quite a unique opportunity, as geoscientists don’t know that much about how oxidation happens in the deep Earth — actually, they weren’t even sure whether it takes place at those depths in the first place.

“On Earth’s surface, where oxygen is plentiful, iron will oxidize to rust,” explained Thomas Stachel, professor in the Department of Earth and Atmospheric Sciences at the University of Alberta, who co-authored the study. “In the Earth’s deep mantle, we should find iron in its less oxidized form, known as ferrous iron, or in its metal form. But what we found was the exact opposite–the deeper we go, the more oxidized iron we found.”

Most of us are familiar with oxidized iron through a process we commonly see on the surface: rust. Image via Pixabay.

The discovery suggests that some oxidation does happen, even at those ungodly depths. Researchers believe the main culprit is molten carbonate, which was carried in sinking slabs of ancient seafloor. However, it’s hard to explain exactly how oxidation happened there in the first place. It’s counterintuitive and hard to explain why the deeper they went, the more oxidized iron they found. Nevertheless, it raises some intriguing possibilities.

“It’s exciting to find evidence of such profound oxidation taking place deep inside the Earth,” said Stachel, Canada Research Chair in diamonds.

Unfortunately, this study raises more questions than it answers. We know a lot about the carbon cycle on the Earth’s surface, but what happens in the mantle? This study seems to indicate that carbon can go down as far as 550 kilometers below the surface, where it interacts with the rocks and crystallizes as diamonds. But diamonds can migrate even deeper in the mantle. Does this mean, that the carbon cycle too extends this low? The study seems to suggest it, but if this is the case, then where does the oxygen come from, and how is the process different from what happens at the surface? Those are all questions to be answered by future research.

The study “Oxidized iron in garnets from the mantle transition zone,” was published in Nature Geoscience (doi: 10.1038/s41561-017-0055-7).

Scientists have long throught that high temperature and pressure deep in Neptune and Uranus' atmosphere are enough to form diamond rain. Now, we have lab confirmation of this hypothesis. Credit: Greg Stewart / SLAC National Accelerator Laboratory.

Diamond rain of Neptune and Uranus mimicked in the lab by scientists

Scientists fired lasers onto the humble polystyrene to recreate a luxurious sight thought to be common on the farthest-flung planets of the solar system: diamond rain.

Scientists have long throught that high temperature and pressure deep in Neptune and Uranus' atmosphere are enough to form diamond rain. Now, we have lab confirmation of this hypothesis. Credit: Greg Stewart / SLAC National Accelerator Laboratory.

Scientists have long throught that high temperature and pressure deep in Neptune and Uranus’ atmosphere are enough to form diamond rain. Now, we have lab confirmation of this hypothesis. Credit: Greg Stewart / SLAC National Accelerator Laboratory.

The two blue marbles of Neptune and Uranus are the least visited planets in our Solar System. Up until now, the only vehicle that has ever visited Uranus and Neptune was NASA’s Voyager 2, which launched in 1977. This flyby, however, raised more questions than it answered. For instance, these two outermost planets of the solar system are some times referred to as the ‘ice giants’ but the reality is we don’t know that much about what they’re made of. We know both have a solid core, that temperatures and pressure can be very high or that both have a dense atmosphere. We don’t know very specifically what’s inside behind their blue blankets since all the data we have comes from a single flyby mission and Earth-based telescope.

This massive gap in knowledge might hopefully be bridged if a NASA mission to send three orbiters to Uranus and Neptune by 2030s gets the resources it needs. Until then, scientists have to do with what they got.

British researchers, for instance, have mimicked the atmospheric conditions on both planets to test whether a long-standing and curious assumption has any footing. For many years scientists have posited that it rains diamonds on both planets, a hypothesis that has long proved very tricky to confirm in the lab. But now, an international team of scientists led by Dominik Kraus from German research lab Helmholtz-Zentrum Dresden-Rossendorf has finally done it.

A diamond furnace

To achieve their goal, the team fired a high-power laser at polystyrene, a common household material here on Earth but also a complex molecule that mimics the hydrocarbon soup seen in the atmosphere of the ice giants. Inside a treated environment, when the first laser pulse hit the foam, an initial shock wave was ejected. A second shock wave, this time faster, was made by a second pulse. When the two waves met, some very extreme conditions were created: temperatures and pressures of about 5,000 Kelvin and 150 GPa or roughly about as hot as the sun’s surface and one a half million times more pressure than at Earth’s sea level, respectively.

All of this was hot enough to break the bonds between the carbon and hydrogen inside the polystyrene. The pressure was also high enough to cause the carbon to bind together and form diamonds, which the scientists observed in minute molecular detail using very short pulses of X-rays.

Inside the lab, it rained with nanoparticles of diamonds but inside Neptune’s atmosphere, these might be far bigger, the team reported in Nature Astronomy. 

Once these diamond drops fall on the planet’s surface, they’ll sink down to the very bottom. This is another reason why this paper is neat. You see, for some time physicists have been debating the structure of both planets. It’s thought that the atmosphere — the outermost layer – is made of hydrogen, helium, and methane, which sits atop a liquid hydrogen layer including helium and methane. The lowest layer is liquid hydrogen compounds, oxygen, and nitrogen, while the core is thought to be made of ice and rock. Now, these little diamonds will help other scientists better test and piece together what these planets’ structure looks like.

“These diamonds will sink down because they are heavier than the surrounding medium and when they sink down there will be friction with the surrounding medium, and at some point they will be stopped when they reach the core – and all this generates heat,” Kraus told The Guardian. 

There might also be a practical dimension to the team’s findings. Kraus says that the market is in demand for artificial diamonds and some applications require finely sized ones — sounds like a perfect fit to me, though it remains to be seen whether it will also be economically feasible.

In any event, it’s amazing to not only hear about how it might rain freaking diamonds on an alien planet but also get a chance to experiment and prove it could happen.

Huge, rare diamonds help us learn more about the Earth’s mantle

Geologists analyzing diamonds of exceptional size and quality have uncovered new clues about the Earth’s geology. By analyzing their chemistry and structure, researchers were able to infer things about the Earth’s mantle, an area inaccessible to direct research.

Diamonds can be used in jewelry… or they can help us better understand the planet’s geology. Image credits: Jennifer Dickert

Diamonds, despite being really expensive, are not entirely that rare. In fact, they’re routinely used in several industrial branches. But big diamonds on the other hand, that’s a completely different story – they’re not only much rarer, but also significantly different. Large gem diamonds like the Cullinan have a unique set of physical characteristics.

“Some of the world’s largest and most valuable diamonds, like the Cullinan or Lesotho Promise, exhibit a distinct set of physical characteristics that have led many to regard them as separate from other, more common diamonds. However, exactly how these diamonds form and what they tell us about the Earth has remained a mystery until now,” explains Dr. Wuyi Wang, GIA’s director of research and development, and an author of the study.

Some of these diamonds grow to such sizes because they were formed in the depths of the Earth, at 360-750 km below the surface (approximately 224-466 miles), in the convecting mantle – much lower than most diamonds which generally form at 150-200 km (approximately 93-124 miles). Being formed at these depths, some of them carry within chemical inclusions from that part of the mantle  – a solidified mixture of iron, nickel, carbon and sulfur, with some traces of fluid methane and hydrogen in the thin tiny space between the metallic phases and the encasing diamond. As diamonds grow, small droplets of metallic liquid were occasionally trapped within. In other words, they encase within them a part of the deep mantle’s chemistry, providing us with a direct example of something we would normally just infer.

“This new understanding of these large, type IIa diamonds resolves one of the major enigmas in the study of diamond formation — how the world’s largest and most valuable diamonds formed,” says Smith. “The composition of the inclusions, however, provides the story.”

Of course, sampling the biggest (and most expensive) diamonds in the world is hardly possible. But big diamonds are always polished and some parts (the scratchings) are not that interesting for jewelers. Normally, these scratchings would also be unavailable, but Smith and his team were lucky enough to be given permission for study. What they want to see now is whether this chemical distribution is localized, or is found everywhere throughout the mantle.

“Previous experiments and theory predicted for many years that parts of the deep mantle below about 250 km depth contain small amounts of metallic iron and have limited available oxygen. Now, the metallic inclusions and their surrounding methane and hydrogen jackets in these diamonds provide consistent, systematic physical evidence to support this prediction,” explains Smith.

Journal Reference: E. M. Smith, S. B. Shirey, F. Nestola, E. S. Bullock, J. Wang, S. H. Richardson, W. Wang. Large gem diamonds from metallic liquid in Earths deep mantle. Science, 2016; 354 (6318): 1403 DOI: 10.1126/science.aal1303

Diamond

Australian researchers develop harder-than-diamond artificial diamond

A team of Australian researchers has developed a method of producing a harder-than-diamond diamond in the lab.

Diamond

Image via Youtube.

Up to the start of December, diamonds were the hardest natural material on Earth. Now that title has been taken, confusingly enough, also by a diamond — not a natural one, but one created in an Australian lab.

Known as Lonsdaleite and first found at the cores of meteorite impacts throughout the world, this type of diamond is special because of its crystalline lattice — the way atoms order themselves. Typical diamonds are made up of carbon atoms arranged in a cubic lattice, which looks like this:

Diamond Cubic Lattice

Stacks upon stacks of this.
Image credits H.K.D.H. Bhadeshia / Wikimedia.

The cubic structure is mainly dictated by carbon’s valency of 4 (meaning each atom tries to tie to 4 others around it) and is extremely resistant. Lonsdaleite, however, has a hexagonal lattice that makes it up to 58% harder than regular diamond. It’s so strong, in fact, that one of the most immediate uses the team suggests for Lonsdaleite is in mining, where it can be used to cut through ultra-solid materials — such as other diamonds.

The team created the new diamond by nanoengineering it from scratch — they basically built it piece by piece from amorphous carbon, a type of the element which doesn’t have a set form.

“We’ve been able to make it at the nanoscale and this is exciting because often with these materials ‘smaller is stronger’,” said lead researcher Jodie Bradby from the Australian National University.

Compare this to the cubic structure of regular diamond.
Image credits Materialscientist / Wikimedia.

They created the diamond by pressing amorphous carbon in a device called a diamond anvil. It’s made up of two opposing diamonds that are pressed into each other to recreate the huge lithologic pressures found at the depths where diamonds form inside Earth.

Using this device, the diamonds can be produced at temperatures of “just” 400 degrees Celsius (752 degrees Fahrenheit). That’s almost 50% less than required for previous methods, meaning they’re a lot cheaper to churn out even though they’re a lot harder than regular diamonds. You can see the device in action in this video:

The team is now conducting tests to determine exactly how hard their diamonds are compared to existing alternatives — although, if natural Lonsdaleite is anything to go off it’s probably pretty hard.

“This new diamond is not going to be on any engagement rings. You’ll more likely find it on a mining site,” said Bradby.

“Any time you need a super-hard material to cut something, this new diamond has the potential to do it more easily and more quickly.”

The full paper “Nanocrystalline hexagonal diamond formed from glassy carbon” has been published in the journal Scientific Reports.

Inclusion

Evidence of water 1,000 kilometers under the surface found locked inside a diamond

Analysis of a mineral inclusion in a 90-million-years-old diamond revealed that the Earth’s mantle might hide a lot more water than we believed, buried as deep as 1,000 kilometers below the surface.

Inclusion

Image credits Mederic Palot.

Water one-third of the way to the Earth’s core – it’s a revolutionary idea. But it’s one that a diamond, spewed out by a volcano near the São Luíz river in Juina, Brazil, some 90 million years ago, seems to point at. The discovery came from analysis of a sealed inclusion, an imperfection in the stone, which contains minerals trapped by the forming diamond.

Through infrared microscopy, scientists analyzing the material found it included hydroxyl ions in its chemical make-up, a compound usually formed from water molecules. And there were a lot of these ions present in the inclusion. But just finding out there was water around where the diamond was one thing – the team also had to determine the depth at which this happened. Once again, they turned their eyes to the inclusion.

They found it was mainly composed of ferropericlase, a mixture of iron and magnesium oxide which can absorb some other metals, such as chromium, aluminum, and titanium, in the extremely hot and pressurized environment of the lower mantle. Jacobsen found that these “extra” metals had separated from the ferropericlase, a phenomena that can only take place in milder conditions as the diamond inches towards the surface. Based on the composition, they estimate the inclusion formed at around 1,000 kilometers deep. The inclusion was sealed in the diamond since the beginning, and for the metals to be present at all, it had to have originated in the lower mantle. That means the water signature can only come from the lower mantle.

“This is the deepest evidence for water recycling on the planet,” he says. “The big take-home message is that the water cycle on Earth is bigger than we ever thought, extending into the deep mantle.”

“Water clearly has a role in plate tectonics, and we didn’t know before how deep these effects could reach,” he says. “It has implications for the origin of water on the planet.”

The findings could support the theory that the Earth had always had water, instead of having it shuttled in by comets and other space rocks.

The full story appeared in print, New Scientists issue 3101, under the headline “Oceans of water in deep Earth go 1000 km down.

 

New method developed to encode huge quantity of data in diamonds

A team from the City College of New York have developed a method to store data in diamonds by using microscopic defects in their crystal lattice.

Image credits George Hodan / Publicdomainpictures

Image credits George Hodan / Publicdomainpictures

I’ve grown up on sci-fi where advanced civilizations stored immense amounts of data in crystals (like Stargate SG-1. You’re welcome). Now a U.S. team could bring the technology to reality, as they report exploiting structural defects in diamonds to store information.

“We are the first group to demonstrate the possibility of using diamond as a platform for the superdense memory storage,” said study lead author Siddharth Dhomkar.

It works similarly to how CDs or DVDs encode data. Diamonds are made up of a cubic lattice of carbon atoms, but sometimes an atom just isn’t there. So the structure is left with a hole — a structural defect. They’re also referred to as nitrogen vacancy centers as nitrogen atoms align themselves to the defects.

These vacancies are negatively charged (as there are no protons to offset the electrons’ charge from neighboring atoms). But, the team found that by shining a laser on the defects — in essence neutralizing their electrical charge — they could alter how each vacancy behaved. Vacancies with a negative charge fluoresced brightly, while those with neutral charges stayed dark. The change is reversible, long-lasting, and stable under weak and medium levels of illumination, the team said.

So just as a laser can be used to encode data on a CD’s medium, it can be turned to storing data by changing these defects’ charges. In theory, this method could allow scientists to write, read, erase, and re-write the diamonds, the team added.

Dhomkar said that in principle, each bit of data can be encoded in a spot a few nanometers — a few billionths of a meter — wide. This is a much denser information packing than in any similar data storing device. So we could use diamonds to build the superdense computer memories of the future. But, we currently have no way to read or write on such a small scale so currently “the smallest bit size that we have achieved is comparable to a state-of-the-art DVD,” Dhomkar told Live Science.

Here “but nr.2” comes into the picture. We can’t yet fully use the diamonds’ capacity, but the team has shown they can encode data in 3D by stacking layers of 2D data stores.

“One can enhance storage capacity dramatically by utilizing the third dimension,” Dhomkar said.

By using this 3D approach, the technique could be used to store up to 100 times more data than a typical DVD. Dhomkar and his team are now looking into developing ways to read and write the diamond stores with greater density.

“The storage density of such an optimized diamond chip would then be far greater than a conventional hard disk drive,” he said.

The full paper “Long-term data storage in diamond” has been published in the journal Science Advances.

How to make diamond rings at Mach speed

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Source

I am almost every time put in a trance whilst spectating an aircraft/jet takeoff. There is always something interesting in the occurrence that makes me go nuts!

And this time around, there are these series of rings that one can see in the exhaust plume of a jet engine when it takes off (usually when the afterburner is on).

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I had no clue about the phenomenon nor did I know how to express it in ‘search engine’ terms to find a match.

But upon discussion with some of friends, I was shown this video of a space shuttle launch that seemed to produce a similar pattern.

Hmm.. Interesting

tumblr_inline_o2xr53pMNF1srob4n_500

Shock Diamonds

These set of rings/disks that are formed in the exhaust plume are known as Shock Diamonds or Mach discs (and by many more names).

These usually form at low altitudes when the pressure of the exhaust plume is lower than the atmospheric pressure.

How does it form ?

Since the atmospheric pressure is higher than the exhaust, it will squeeze it inward. This compresses the exhaust increasing its pressure.

The increased pressure also instills an increase in temperature.

As a result, this ignites any excess fuel present in the exhaust making it burn. It is this burning that makes the shock diamond glow.

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Source

The pressure is now more than the atmospheric pressure, and the exhaust gases start to expand out.

Over time, the process of compression and expansion repeats itself until the exhaust pressure becomes the same as the ambient atmospheric pressure.

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In other words, the flow will repeatedly contract and expand while gradually equalizing the pressure difference between the exhaust and the atmosphere.

The same occurs in rocket engines as well.

What if?

What if the atmospheric pressure is less than the exhaust plume ( like at higher altitudes ), would we still see shock diamonds?

Yup, we would! And here’s a picture of it too (The Bell X-1 at speeds close to Mach 1).

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The same phenomenon as discussed above occurs except that the cycle starts with the exhaust gases expanding to atmospheric pressure first.

Did you enjoy this post?

There is an extensive explanation of shock diamonds given by shock waves which this post does not cover.

And this beckons the start of Supersonic Fluid Dynamics – a marvelous field of its own. If this captivated you, it is definitely worth a google search.

Cheers!

A mixture of nanodiamond and microdiamond Q-carbon created using the new technology. Photo by AIP/ALP Materials

Scientists find new phase of carbon at room-temp that’s harder than diamond

A mixture of nanodiamond and microdiamond Q-carbon created using the new technology. Photo by AIP/ALP Materials

A mixture of nanodiamond and microdiamond Q-carbon created using the new technology. Photo by AIP/ALP Materials

To make diamonds, the industry typically resorts to subjecting graphite to immense pressure and temperature, which makes production volumes low and costly. This paradigm is about to change, since researchers at North Carolina State University found a new phase for carbon called Q-carbon, produced at ambient temperatures and pressure. This is surprisingly close to diamond in structure, with the added benefit of exhibiting a couple of unique properties.

“We’ve now created a third solid phase of carbon (besides graphite and diamond),” says Jay Narayan, the John C. Fan Distinguished Chair Professor of Materials Science and Engineering at NC State and lead author of three papers describing the work. “The only place it may be found in the natural world would be possibly in the core of some planets.”

Q-carbon is actually harder than diamond. Among other things, it glows (a sort of fluorescence) even when exposed to low energy levels and is ferromangnetic. Ferromagnetism manifests itself in the fact that a small externally imposed magnetic field, say from a solenoid, can cause the magnetic domains to line up with each other and the material is said to be magnetized. Thus, a material that isn’t actually a magnetic can act like one for a brief period of time. “We didn’t even think that was possible,” Narayan said, further mystifying the properties of Q-carbon.

To make Q-carbon, you first coast sapphire, glass or a plastic polymer with a layer of non-crystalline amorphous carbon. Then blast the whole material with a very short, but intense laser pulse. The pulse lasts only 200 nanoseconds (200 billionths of a second), but it’s enough to raise the temperature of the carbon to 4,000 Kelvin (or around 3,727 degrees Celsius). By altering the duration of the laser pulse, the researchers can alter the quality and quantity of the carbon. For instance, you can make single crystal or other diamond shapes. Further demonstrating its versatility, the researchers made Q-carbon films ranging from  20 nanometers to 500 nanometers in thickness.

More work and research is required to understand this peculiar new carbon phase. We don’t know for sure how useful Q-carbon is, but it’s readiness to release electrons makes it suitable in the field of electronics. Other uses might follow following closer investigation.

“We can create diamond nanoneedles or microneedles, nanodots, or large-area diamond films, with applications for drug delivery, industrial processes and for creating high-temperature switches and power electronics,” Narayan says. “These diamond objects have a single-crystalline structure, making them stronger than polycrystalline materials. And it is all done at room temperature and at ambient atmosphere – we’re basically using a laser like the ones used for laser eye surgery. So, not only does this allow us to develop new applications, but the process itself is relatively inexpensive.”

“We can make Q-carbon films, and we’re learning its properties, but we are still in the early stages of understanding how to manipulate it,” Narayan says. “We know a lot about diamond, so we can make diamond nanodots. We don’t yet know how to make Q-carbon nanodots or microneedles. That’s something we’re working on.”

Referece: Jagdish Narayan et al. Research Update: Direct conversion of amorphous carbon into diamond at ambient pressures and temperatures in air, APL Materials (2015). DOI: 10.1063/1.4932622

Rock with 30,000 diamonds found Russian diamond mine

Do you fancy diamonds? If the answer is ‘yes’, then you’ll absolutely love this rock extracted from a Russian mine. The rock is littered with over 30,000 diamonds, something which is extremely rare and may yield valuable information about how diamonds form in natural conditions.

What’s unlucky for gem sellers was very fortunate for researchers – because the tiny diamonds are so small, they are pretty much worthless as gems, so they donated the rock for study. Hurray for science!

The rock was extracted from the huge Udachnaya pipe, an open-pit mine located in Russia, just outside the Arctic circle. It’s one of the biggest diamond mines in Europe and in the world. The results were reported by geologist Larry Taylor from the University of Tennessee this week at the American Geophysical Union’s annual meeting.

“The exciting thing for me is there are 30,000 itty-bitty, perfect octahedrons, and not one big diamond,” said Taylor at the meeting. “It’s like they formed instantaneously.”

The Udachnaya pipe. Image via Wiki Commons.

Even thought the diamonds are so small, the concentration of diamonds in the ore is humongous: million times more than usually. This remarkable association of diamonds and other minerals will hopefully reveal the exact chemical reactions which lead to the formation of diamonds on Earth – which are still a mystery. Taylor said:

“The associations of minerals will tell us something about the genesis of this rock, which is a strange one indeed. The [chemical] reactions in which diamonds occur still remain an enigma,” Taylor told Live Science.

Although highly regarded as the a gem and extracted for this purpose for centuries, we still don’t know exactly how diamonds form. According to our current understanding, diamonds are formed at high temperature and pressure at depths of 140 to 190 kilometers (87 to 118 mi) in the Earth’s mantle. Carbon-containing minerals provide the carbon source, and the growth occurs over extremely long periods from 1 billion to 3.3 billion years! Diamonds are then brought close to the Earth’s surface through deep volcanic eruptions by a magma, which cools into igneous rocks known as kimberlites and lamproites. The heat destroys most of the material surrounding the diamonds, but the diamonds still resist. There are also ways of creating artificial diamonds, but the exact chemistry still eludes us.

Diamond formation. Image via GeoScienceWorld.

But while you do see several diamonds on the same rock, you almost never find a rock with so many. Working with researchers at the Russian Academy of Sciences, Taylor analysed the rock using an industrial X-ray tomography scanner to figure out how it ended up with such a staggering amount of diamonds and remained intact when it was raised to the surface.

“The clear crystals are just 0.04 inches (1 millimetre) tall and are octahedral, meaning they are shaped like two pyramids that are glued together at the base,” says Oskin. “The rest of the rock is speckled with larger crystals of red garnet, and green olivine and pyroxene. Minerals called sulphides round out the mix. A 3D model built from the X-rays revealed the diamonds formed after the garnet, olivine and pyroxene minerals.”

The minerals also had some exotic material included in their structure. These inclusions were once fluids that seeped out of the Earth’s oceanic crust when one tectonic plate crashed onto another. These fluids crystallized and became an integral part of the diamonds, much deeper in the earth and much, much later. This is either a very strange and unusual formation, or…

“[The source] could be just a really, really old formation that’s been down in the mantle for a long time,” Sami Mikhail from the Carnegie Institution for Science in the US, who was not involved in the research, told Live Science.

 

 

Artist impression of a possible space elevator - the image in question show the new diamond-like nanomaterial in action, though.

Ultrathin diamond-like thread could help build elevator to space

Artist impression of a possible space elevator - the image in question show the new diamond-like nanomaterial in action, though.

Artist impression of a possible space elevator – the image in question show the new diamond-like nanomaterial in action, though.

For the first time, scientists at Penn State University have coaxed carbon-containing molecules to form a  strong tetrahedron shape, then linked each tetrahedron end to end to form a long, thin nanothread. The resulting materials is stronger than carbon nanotubes, while the thread is only a few atoms across thick, hundreds of thousands of times smaller than an optical fiber. This sort of material might one day help us build an elevator that would carry astronauts or cargo from a point on the Earth’s surface to a geosynchronous docking station in orbit, dramatically lowering costs by eliminating the need for rockets. More immediate, practical goals include manufacturing lightweight vehicles that significantly reduce fuel consumption.

Strong like diamond, thin like air

 The core of the nanothreads is a long, thin strand of carbon atoms arranged just like the fundamental unit of a diamond's structure -- zig-zag 'cyclohexane' rings of six carbon atoms bound together, in which each carbon is surrounded by others in the strong triangular-pyramid shape of a tetrahedron. Image: Penn State University

The core of the nanothreads is a long, thin strand of carbon atoms arranged just like the fundamental unit of a diamond’s structure — zig-zag ‘cyclohexane’ rings of six carbon atoms bound together, in which each carbon is surrounded by others in the strong triangular-pyramid shape of a tetrahedron. Image: Penn State University

The molecule the researchers compressed is benzene – a flat ring containing six carbon atoms and six hydrogen atoms. When compressed, the flat benzene molecules stack together, bend and break apart under pressure. As the pressure is slowly tuned down, atoms reconnect in an orderly fashion to form a structure that has carbon in the tetrahedral configuration of diamond with hydrogens hanging out to the side and each tetrahedron bonded with another to form a long, thin, nanothread. Nothing short of beautiful.

[ALSO READ] Russia declassifies diamond deposit – trillions of carats, enough for the entire world for 3.000 years

This orderly pattern forms because the constituting benzene atoms desperately want to cling onto something else, but at the same time there’s no room to move because of the high pressure. Once the pressure is slowly released, the benzene becomes highly reactive and an orderly polymerisation reaction is commenced.

“We used the large high-pressure Paris-Edinburgh device at Oak Ridge National Laboratory to compress a 6-millimeter-wide amount of benzene – a gigantic amount compared with previous experiments,” said Malcolm Guthrie of the Carnegie Institution for Science, a co-author of the research paper, which was published in Nature Materials.

“We discovered that slowly releasing the pressure after sufficient compression at normal room temperature gave the carbon atoms the time they needed to react with each other and to link up in a highly ordered chain of single-file carbon tetrahedrons, forming these diamond-core nanothreads.”

The researchers liken the process to how a jeweler delicately strings  together the smallest possible diamonds into a long miniature necklace – a very strong, atom-thin necklace.

Close-up of the diamond nanothread structure. Image: Penn State University

Close-up of the diamond nanothread structure. Image: Penn State University

Upon inspecting the structure of the diamond nanothreads, the researchers found parts of these aren’t perfect or at least don’t look as expected. Improving upon its structure is thus an immediate goal for the team right now. Nevertheless, the findings open new doors towards a novel type of research. More materials such as these might be made, ones made from other molecules beside benzene since you can attach all kinds of other atoms around a core of carbon and hydrogen. Thus, an enormous number of new materials, some with extremely appealing properties, might be made. Who knows what we can achieve with these then. For instance, there’s this crazy idea of using diamond nanothreads to build a space elevator. We’ve written about this in the past, but now this research shows that it might be realistic to make.

“One of our wildest dreams for the nanomaterials we are developing is that they could be used to make the super-strong, lightweight cables that would make possible the construction of a “space elevator”, which so far has existed only as a science-fiction idea,” said research leader John V Badding, a professor of chemistry at Penn State, in a statement.

“From a fundamental-science point of view, our discovery is intriguing because the threads we formed have a structure that has never been seen before.”

There’s one problem though, at least for now – scientists need to find a way to scale production if we’re to ever build threads thousands of kilometers long.

“The high pressures that we used to make the first diamond nanothread material limit our production capacity to only a couple of cubic millimeters at a time, so we are not yet making enough of it to be useful on an industrial scale,” Badding said. “One of our science goals is to remove that limitation by figuring out the chemistry necessary to make these diamond nanothreads under more practical conditions.”

Nevertheless, more immediate applications include those where exceedingly strong, stiff, and light materials are required. If the manufacturing process can be scaled to production is cheap enough, we might even see vehicles made out of diamond-like strands. These would be extremely lightweight and use very little fuel. The transportation sector is one of the prime emitters of greenhouse gases, so keeping fuel consumption down will definitely help tackle global warming.

Findings appeared in the journal Nature Materials.

 

Confocal scan of a single cell. The white cross corresponds to the position of the gold nanoparticle used for heating, while the red and blue circles represent the location of diamond sensors used for thermometry. The dotted white line outlines the cell membrane. (Credit: DARPA)

Temperature control and monitoring achieved at the cellular level

Temperature is an important physical parameter which greatly influences a system. Monitoring and/or manipulating this state parameter with great accuracy is thus of great importance to scientists. Recently, researchers part of  DARPA’s Quantum-Assisted Sensing and Readout (QuASAR) program proved a new technique that allowed them to measure and control temperatures at the nanometer scale inside living cells. Measuring temperatures at such fine spatial resolutions will allow for better assessment of the thermal performance of high grade materials, cell-specific treatment and other health related applications.

The QuASAR team, led by researchers from Harvard University, were able to measure sub-degree variations over a large range of temperatures in both organic and inorganic systems at length scales as low as 200 nanometers by using an ingenious set-up, along with gold nanoparticles and tiny diamond sensors. The latter is where the innovative part of the research lies.

Confocal scan of a single cell. The white cross corresponds to the position of the gold nanoparticle used for heating, while the red and blue circles represent the location of diamond sensors used for thermometry. The dotted white line outlines the cell membrane. (Credit: DARPA)

Confocal scan of a single cell. The white cross corresponds to the position of the gold nanoparticle used for heating, while the red and blue circles represent the location of diamond sensors used for thermometry. The dotted white line outlines the cell membrane. (Credit: DARPA)

Diamonds have naturally occurring imperfections known as nitrogen-vacancy (NV) color centers, with each center capable of trapping one electron. Temperatures fluctuations causes the diamond lattice to expand or contract, just like at the macroscale – think of the dilation and contraction of railway tracks when its hot or cold, respectively.

This lattice structure variation also causes changes in the spin properties of the electron, measured using a laser technology, which can then be correlated with temperature.

To demonstrate their research, 100-nanometer-diameter gold particles were implanted  into a human cell alongside the diamond sensors, which the scientists then heated using a heating laser. By monitoring the diamond sensors, researchers could characterize the local thermal environment around the cell. Shifting the power of the heating laser, as well as the gold nanoparticles concentration, allows for modification of the environment.

Using such a technique, researchers could have access to high resolution thermal insight and study, for instance,  nanoscale cracking and degradation caused by temperature gradients in materials and components operating at high temperatures. The electronics industry, where finely-tuned tiny components are at play, might have a lot to benefit. Also, since diamond is inert and thus doesn’t interfere with chemical reactions, the technique could be used to monitor and control chemical reactions at tiny shifts of temperature.

The findings were reported in the journal Nature.