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Is the Earth's Mantle Full of Diamonds? (gizmodo.com)
An anonymous reader quotes a report from Gizmodo: Scientists' models show that sound waves seem to travel too quickly through the old, stable cores of continents, called "cratons," which extend deep into the mantle at depths around 120 to 150 kilometers (75 to 93 miles). Through observations, experiments, and modeling, one team figured that a potential way to explain the sound speed anomaly would be the presence of a lot of diamonds, a medium that allows for a faster speed of sound than other crystals. Perhaps the Earth is as much as 2 percent diamonds by volume, they found. Scientists have modeled the rock beneath continents through tomography, which you can think of as like an x-ray image, but using sound waves. But sound-wave velocities of around 4.7 kilometers per second (about 10,513 mph) are faster than sound-wave velocities in other kinds of minerals beneath the crust, according to the paper in the journal Geochemistry, Geophysics, Geosystems.
The researchers realized that if the regions had either 3 percent diamonds by volume or 50 percent of a rock formed at high pressure and temperature called eclogite, it would enable the sound speeds they observed. But both of those numbers seemed too high, based on observations of the minerals that end up on the Earth's surface: diamond-containing rocks called kimberlites. The researchers compromised and figured that 20 percent eclogite and 2 percent diamonds could explain the high velocities. The diamonds could be sprinkled as crystals found uniformly throughout the cratons.
The researchers realized that if the regions had either 3 percent diamonds by volume or 50 percent of a rock formed at high pressure and temperature called eclogite, it would enable the sound speeds they observed. But both of those numbers seemed too high, based on observations of the minerals that end up on the Earth's surface: diamond-containing rocks called kimberlites. The researchers compromised and figured that 20 percent eclogite and 2 percent diamonds could explain the high velocities. The diamonds could be sprinkled as crystals found uniformly throughout the cratons.
So the answer to the head line is NO, it is not full, it is maybe 2% by volume. Utah beer has more alcohol than that...
Haven't you guys seen "The Core"?
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Enthusiastic? Nobody is going to commercially mine the mantle for diamonds. Even the deepest oil wells are only a few miles. At any rate, diamonds are the most common gem on the surface.
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IANAGP/C... ...BUUUT, the 8th element by atomic number just ain't that rare in the cosmos.The general asshattery of the DeBeers family and corp aside, the fact that we've known about one of its molecular allotropes for most of our written history SHOULD tell us that allotrope ain't that rare on Earth, either. Yeah, you need special conditions to press a 2-d lattice into a 3-d lattice, but we're doing that in labs with, literally, waste gasses from sewage. The fact that uur pressure-cooker of a planet's interior does the same thing should come as a surprise to small children and the illiterate..
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