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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.
Diamonds AREN'T that rare which is why resale is so bad on them. The only reason we think they are rare is because De Beers Consolidated Mines, Ltd wants us to BELIEVE they are.
Errr no. It's not very specialised at all. Cutting gems is quite easy. A month or two of on the job training and you'll be cranking out some beauties. Getting trained up to the point of being able to cut expensive diamonds is not difficult feat and doesn't require any training that you don't get on the spot.
So the only explanation to "sound waves seem to travel too quickly through the old, stable cores of continents" is "the presence of a lot of diamonds". A bit over enthusiastic imo.
Well, let's ask the experts:
These constraints suggest that diamond and eclogite are the most likely high-Vs candidates to explain the observed velocities, but matching the high shear-wave velocities requires either a large proportion of eclogite (>50 vol.%) or the presence of up to 3 vol.% diamond, with the exact values depending on peridotite and eclogite compositions and the geotherm
So the experts show that your claim is false, diamond isn't the only explanation. It is one of many explanations, and is one of two that are the most likely out of all of them.
You are going to need to show far more evidence for your claim of "the only explanation" than nothing before it is seriously entertained.
For what it's worth, I do agree that your claim, a seemingly baseless one at the moment, is very overly enthusiastic. But I'd be willing to change that opinion if you'd share the reasoning and/or evidence for your claim that diamonds are the only option.