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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.

109 comments

  1. Yes. by xxxJonBoyxxx · · Score: 2

    Yes.

    1. Re:Yes. by JMJimmy · · Score: 2

      So what you're really saying is that there are 21 600 000 000 cubic kilometers worth of diamonds and they really are just worthless rocks - not worth the thousands people spend on them. Yes, it makes perfect sense.

    2. Re:Yes. by xxxJonBoyxxx · · Score: 1

      Actually, no.

    3. Re:Yes. by TheRealQuestor · · Score: 5, Informative

      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.

    4. Re:Yes. by Anonymous Coward · · Score: 0

      The mantle is basically a giant oven.

    5. Re:Yes. by Bonker · · Score: 4, Insightful

      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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    6. Re:Yes. by hcs_$reboot · · Score: 1

      Diamonds might not be that rare, but the manual work to make them marketable is a rare competence.

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    7. Re:Yes. by thegarbz · · Score: 5, Informative

      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.

    8. Re:Yes. by SeaFox · · Score: 2

      Diamonds AREN'T that rare which is why resale is so bad on them.

      It's also why it doesn't matter if the Earth's mantle is full of diamonds. If it is, and we were to suddenly get access to them, we wouldn't be rich because we would have just crashed the diamond market.

    9. Re:Yes. by Anonymous Coward · · Score: 0

      "Month or two and you'll be cranking out some beauties!" , LOL!

      Do you know many gem cutting apprentices? Have lots of practical experience as a diamantaire? Pffft cutting expensive diamonds is just SO easy. You cut expensive diamonds all the time, and it's easy as pie. Just get some spare diamonds and start chopping.

    10. Re:Yes. by Opportunist · · Score: 1

      Want to bet that DeBeers would find another way to protect their de facto monopoly? It's not like they are the only ones who could sell diamonds due to availability, but curiously, some reason exists...

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    11. Re:Yes. by gravewax · · Score: 2

      ahhhh no, it is a very common skill. Again you have been listening to De Beers PR BS.

    12. Re:Yes. by Anonymous Coward · · Score: 3, Interesting

      you don't start on expensive ones, you start on crappy flawed ones, it isn't expensive to learn or particularly difficult, one of my friends now does it professionally. Nowdays it is easier than ever with computers and lasers to do all the measurements to work out the best way to cut and shape it, one of the difficult skills used to be that, now that skill is barely necessary at all.

    13. Re:Yes. by Anonymous Coward · · Score: 0

      You can even make them from...

      !!!TEQUILA!!!

      The guys who did this got an Ig Nobel prize. They were cool.

    14. Re:Yes. by Anonymous Coward · · Score: 0

      That's why we have leper gnomes in the basement.

    15. Re: Yes. by aliquis · · Score: 1

      Similarly you think your money is worth something while others create them out of nothing at the volume of whatever amount of trillions and then buy something which is actually more limited for the profits they make.

    16. Re:Yes. by Anonymous Coward · · Score: 0

      In the related news, De Beers Consolidated Mines, Ltd announced a brave and courageous program to protect their rightful place in the market for girl's best friends: attaching thrusters to Venus to make it collide with Earth.

    17. Re:Yes. by Anonymous Coward · · Score: 0

      He was just talking about the supply of diamonds, not what you would be willing to pay for diamonds. It might be that you should still be paying many thousands of dollars for these diamonds even though they're plentiful, because .. hey, the applications!!

    18. Re:Yes. by Anonymous Coward · · Score: 0

      Sell DeBeers!

    19. Re:Yes. by JMJimmy · · Score: 2

      The diamond market is already being propped up - multiple massive deposits in Russia aren't being mined.

    20. Re:Yes. by Anonymous Coward · · Score: 0

      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.

      A simple way to find the real value of diamonds is: try to sell one.

      You'll find it *very* quickly.

    21. Re:Yes. by Anonymous Coward · · Score: 0

      IANAGP/C... ...BUUUT, the 8th element by atomic number just ain't that rare in the cosmos.

      Yeah. In the beginning there was carbon. Then came the Late Heavy Bombardment, and there were diamonds.

    22. Re:Yes. by Darinbob · · Score: 1

      Except that you can't easily resell those heirlooms, even at the current market price! Jewelry stores often buy diamonds on consignment from wholesalers. And the wholesalers don't want your diamond either. So it's already cut, it looks perfect, but you can only sell the thing for about 25% of what seems to be the market price.

      The demand for new diamonds is artificially created by marketing, and such a market didn't exist for the average public more than about a century ago. The idea of spending X% of your salary on a wedding ring was made up entirely by DeBeers marketing, along with the idea that it must be diamond and never another gem. Because so much of the diamond's value is entirely based on perception, this is what ruins diamonds for resale or as a commodity.

      That's why you save grandma's ring. You save a ton of money for a product that is as good or better than the modern product, and because it's a family heirloom it has more perceived value than getting a used heirloom from someone else.

    23. Re:Yes. by Darinbob · · Score: 1

      Why settle for a common dirt diamond when you can get a top of the line Tiffany's diamond cluster that comes with an authenticated pedigree certificate showing that they came from the most exclusive slave mines, each hand polished on the bosoms of the most highly paid reality TV starlets?

    24. Re:Yes. by KingBenny · · Score: 1

      and a good reason to phracking crack that shit open to the core ... split it halfways, then blame the russians

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  2. Diamonds from the microwave by thesjaakspoiler · · Score: 1

    Why dig down 120 kilometer if you make them yourself ? https://www.youtube.com/watch?...

    1. Re:Diamonds from the microwave by hcs_$reboot · · Score: 2

      Five long minutes of pure BS.

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    2. Re:Diamonds from the microwave by Ranbot · · Score: 1

      Maybe not DIY diamonds, but laboratory-made synthetic diamonds are now being sold in regular jewelry stores for 30-40% less than natural diamonds. Read more here; https://www.nytimes.com/2018/0...

    3. Re:Diamonds from the microwave by Anonymous Coward · · Score: 0

      Synthetic diamonds have been sold as jewelry since the 60s. Anyone telling you a store diamond isn't synthetic is lying.

    4. Re:Diamonds from the microwave by Anonymous Coward · · Score: 0

      Five long minutes of pure BS.

      Still you went for it. Life is short.

  3. What the headline.. by Anonymous Coward · · Score: 2, Insightful

    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...

  4. I have a different hypothesis by mnemotronic · · Score: 5, Funny

    The lithospheric mantle is composed of politicians; an incredibly dense material. Sound waves and thermal gradients pass easily through this layer. Money, on the other hand, is readily absorbed by the same material. Strangely, truth is reflected but with, as yet, explainable phase shifts or distortions.

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    1. Re:I have a different hypothesis by Opportunist · · Score: 1

      So ... you say the religious are right? Hell is right below us?

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    2. Re:I have a different hypothesis by Anonymous Coward · · Score: 0

      You're wrong if by that you mean that the nice part is above our heads, and the bad part is below our feet. Why else would all religious people want to get buried closer to the bad part than the good part?

      It's the other way around, you see?

      Deep down under is the nice part. It's all just marketing making us believe the exact opposite by politicians and elite who of course keep going deep.

      This is probably why the waves of those scientists got reflected. There have been a lot of elite going deep into the earth's mantle for many years, where their bodies cocoon and then transform into lizards.

    3. Re:I have a different hypothesis by turp182 · · Score: 1

      Here's a political from the British Wood Party falling into the Earth's crust, courtesy of Monty Python:
      https://www.youtube.com/watch?...

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    4. Re:I have a different hypothesis by ebvwfbw · · Score: 1

      If you're worried about it, just become a Jew. There is no heaven nor hell in that religion. They will cut you when you join the church, however.

    5. Re:I have a different hypothesis by RockDoctor · · Score: 1

      Sound waves and thermal gradients pass easily through this layer. Money, on the other hand, is readily absorbed by the same material.

      That would explain the (relatively small) sums of money sunk into Project Mohole.

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  5. Hmmm by hcs_$reboot · · Score: 2

    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.

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    1. Re:Hmmm by Gavagai80 · · Score: 3, Insightful

      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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    2. Re:Hmmm by hcs_$reboot · · Score: 1

      Would that be diamonds or glass or whatever, "enthusiastic" refers to how definitive and assured the conclusion is made, at depths we know almost nothing.

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    3. Re:Hmmm by Anonymous Coward · · Score: 1

      Well, we know quite a lot about the behaviour of sound at those depths - "know almost nothing" is pretty vague and useless. And carbon is common and the conditions at those depths are conducive to diamond formation, so this isn't the huge leap you seem to think it is. Moreover, "glass" is a pretty general name for a lot of materials, most of which won't behave down there as they do up here, so seems unlikely they'd be criticized for "oops forgot to test for 'glass'".

      "Definitive and Assured" - doesn't sound like you actually read the paper. They look at some alternatives, and list alternatives they didn't study, which is just how it should be. What else would you do? Or are you referring to the gizmodo write-up - in which case, meh, and I think you'd make more sense if you targeted your criticism at them.

      Please be aware, your broad-brush opinionated scepticism makes you sound like a tit. I'm sure you're a nice person most of the time - why not give these guys some credit?

    4. Re:Hmmm by Anonymous Coward · · Score: 1

      The researchers studied an observed anomaly, formulated a hypothesis, and did some modeling to see whether the hypothesis was plausible and the conditions under which it might hold. Sounds like science to me.

    5. Re:Hmmm by Anonymous Coward · · Score: 0

      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.

      If you read TFA, this is what the "researcher" said... tldr -- we need to bullshit the cause from our observation.

      “We had all of these observations of sound speeds and needed something to explain them,” Ulrich Faul, research scientist at MIT’s Department of Earth, Atmospheric, and Planetary Sciences, told Gizmodo. “We ended up with diamonds.”

    6. Re:Hmmm by avandesande · · Score: 1

      While I don't think drilling on Mars for diamonds makes any sense I wonder how hard it would be to drill deeply with the reduced gravity and colder interior?

      --
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    7. Re:Hmmm by Anonymous Coward · · Score: 2, Informative

      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.

  6. Of course it is! by DontBeAMoran · · Score: 5, Insightful

    Haven't you guys seen "The Core"?

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    1. Re:Of course it is! by hcs_$reboot · · Score: 1

      5.5 on iMDB... no and don't plan to.

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    2. Re:Of course it is! by Anonymous Coward · · Score: 0

      That's actually not a bad score. People generally think that anything below 7 must be bad but that's not what those IMDB ratings mean. 4 and under are the ones you stay away from, 5ish and up are OK.

    3. Re:Of course it is! by hcs_$reboot · · Score: 1

      Everything is relative, Einstein. Some people like 4.0 movies ... Based on my experience, under 7 is a 90% crap chance, under 6 99% chance of being a crappy movie.

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    4. Re: Of course it is! by Type44Q · · Score: 1

      It is not sci-fi for thinking people, that's for sure.

    5. Re:Of course it is! by Anonymous Coward · · Score: 0

      That's actually not a bad score. People generally think that anything below 7 must be bad but that's not what those IMDB ratings mean. 4 and under are the ones you stay away from, 5ish and up are OK.

      I have had fun with 3-rated movies. Cinema critics are not a very good at assessing entertainment for the masses.

    6. Re:Of course it is! by datavirtue · · Score: 1

      Sometimes 1-2 start movies are quite entertaining. Letting the unwashed masses rate movies does not yield a reliable metric.

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    7. Re:Of course it is! by Anonymous Coward · · Score: 0

      The best part of "The Core" is the way that it inspired one of the best South Park episodes :"http://www.southparkstudios.nu/full-episodes/s09e02-die-hippie-die"

  7. Only 75 miles? by Anonymous Coward · · Score: 1

    So all you have to do is figure out a way to mine at a depth 30 times
    deeper than the worlds deepest mine.
    Piece of cake.

    1. Re:Only 75 miles? by hcs_$reboot · · Score: 1

      Plus conditions change... pressure (40 kbar), temperature ...

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    2. Re:Only 75 miles? by jwhyche · · Score: 2

      A better plan would be to find a large iron asteroid in the outer solar system. Then direct it around the sun a few times to pick up speed. Then slam it into the planet. I'm picturing a rifle bullet through a water melon here. That way instead of just the diamonds you can get at all the inner earths goodies.

      Of course I think there might be another problem with this plan. I just can't think of it right now.......

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    3. Re:Only 75 miles? by datavirtue · · Score: 1

      ...hot as hell and no doubt filled with hazards unimaginable

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  8. No. by Anonymous Coward · · Score: 0

    If there were any diamonds in the Earth's mantle they would have been secured in a De Beers vault by now.

    1. Re:No. by Aristos+Mazer · · Score: 3, Funny

      Or the core of Earth *is* De Beers' vault?

    2. Re:No. by Opportunist · · Score: 2

      Well, they have been known to create artificial scarcity by limiting supply due to stockpiling...

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  9. Re:Diamonds are Forever by Anonymous Coward · · Score: 0

    Nope. You mistook me. I had plenty of guns before they all sunk in a boating accident.

  10. Re:Diamonds are Forever by Anonymous Coward · · Score: 0

    Sank...damn it.

  11. Cratons? by 93+Escort+Wagon · · Score: 2

    Sounds like one of those weird creatures L Ron Hubbard came up with.

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    1. Re: Cratons? by Type44Q · · Score: 1

      Tom Cruise??

    2. Re:Cratons? by koomba · · Score: 1

      Pretty common geological term, if you took any high school level or higher geology class, you would know the term. It's nothing complicated.

      A craton is basically an old, stable part of the earth's crust, which generally make up the core of all the major tectonic plates. It's the part that has survived the cycles of subduction, so it's usually roughly in the center of the tectonic plate. For example, the Canadian Shield is the craton that makes up the core of the North American plate, and has some of the oldest identified rocks on the planet in it.

  12. One Word by Anonymous Coward · · Score: 0

    DeBeers.

    Don't matter if diamonds come out of Trump's vagina, DeBeers will claim ownership and hoard them.

  13. De Beers by tsa · · Score: 1

    The De Beers company probably has known this since the 1950s or so.

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  14. Drill baby drill! by Anonymous Coward · · Score: 0

    Diamonds are carbon and can be burned as fuel. Of course you have to cursh and grind it to increase surface area and probably need pure oxygen to start the fire.
    Come on people, we can turn Earth to Venus by burning diamonds!

  15. Sure it is. Leave'em there! by aglider · · Score: 1

    But if you dug all those shiny crystals their value would rapidly approach zero.

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    1. Re:Sure it is. Leave'em there! by hcs_$reboot · · Score: 1

      Good luck to dig at this depth (40 kbar)

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    2. Re: Sure it is. Leave'em there! by aglider · · Score: 1

      Mankind fan ne really stupid.

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    3. Re: Sure it is. Leave'em there! by hcs_$reboot · · Score: 1
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    4. Re:Sure it is. Leave'em there! by drinkypoo · · Score: 1

      But if you dug all those shiny crystals their value would rapidly approach zero.

      If you only dug all those shiny crystals out of DeBeers' vaults, their value would rapidly drop below all precious stones — because it would be only semi-precious.

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    5. Re:Sure it is. Leave'em there! by Anonymous Coward · · Score: 0

      DeBeers would just launch a marketing campaign against mantle diamonds. "Give her what she really wants: a diamond peacefully extracted from the Earth's crust and laser-engraved to guarantee authenticity, not a fake synthetic diamond made in a cold and sterile lab or a diamond crudely ripped from the depths of hell. DeBeers, totally not pumping up worthless rocks by artificially restricting supply and defaming alternate sources for chemically identical rocks since 1888."

  16. Lucy is here! by Evtim · · Score: 1

    I repeat: Lucy is here....and we thought we need to travel 5.2 AU to get to her :)

    1. Re:Lucy is here! by Opportunist · · Score: 1

      But ... not in the sky but in the ground?

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    2. Re:Lucy is here! by Tukz · · Score: 1

      So...it was all about LEDs instead of LSD?

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  17. the 8th element by Anonymous Coward · · Score: 1

    Element 8 is oxygen, and no, that's not rare at all. It forms a large part of the Earth's mantle, crust and oceans.

  18. High density superstructure by poity · · Score: 1

    of a starkiller base

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  19. there is no shortage of diamonds! by Anonymous Coward · · Score: 0

    earth is full of them!
    it is just a artificial shortage orchestrated by one actor.
    And as soon as we dig up tones at the time they will go bust and the price will normallise to 5-10$/ct as it prob should be.
    They are already doing all they can to paint artificial diamonds as something bad... Just ask your wife if she wants a artificial diamond ring or a "real" one.
    even though you cant see a difference other than in certain light. And reading the "certification" number that they made up.

  20. Diamonds are rare by ThinkNextTime · · Score: 0

    Only in comparison to #2 pencils. And maybe not even then. I suspect many households have more diamonds than pencils. If you want something both spectacular and rare, try a Paraiba tourmaline. Even flux grown gemstones are far rarer than diamond. Why support DeBeers? And if shes not going to live forever, why buy her a diamond?

  21. My God... by zifn4b · · Score: 2

    ...It's full of diamonds!

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  22. But, Hillary Swank by Anonymous Coward · · Score: 0

    That adds at least two points.

    1. Re:But, Hillary Swank by hcs_$reboot · · Score: 1

      Nope. The 2 points are already in. Actual rating is 3.5.

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  23. Re: Diamonds are Forever by Anonymous Coward · · Score: 0

    Education after mining the diamonds is cart before the horse.

    As in, who the fuck is going going to pay a lot for rocks if everyone has them? Economics 101 says nobody.

  24. Deep in the mantle by Anonymous Coward · · Score: 0

    "which extend deep into the mantle at depths around 120 to 150 kilometers (75 to 93 miles)."

    The mantle is 1,793 miles thick. Continental crust is 20 to 30 miles thick.

    75 to 93 miles minus 20 to 30 miles, all divided by 1793 miles, = 2.5% to 4.1% of the way into the mantle, and this is "deep in the mantle"?

    The piece of paper cut deeply into me when I picked it up off the copier.

  25. watermelon size diamonds by k6mfw · · Score: 1

    Some years ago I read way deep down there are diamonds the size of watermelons. By the time they make it to surface (million years or more?) they are broken up into much smaller pieces. Imagine a diamond that big, how much would it weigh? What about polishing it and trim it? Be a damn shame if a jeweler intended to trim the edge but hit it in such a way it shatters into little pieces like a car rear window.

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  26. NO by houghi · · Score: 1

    It is turtles. Turtles all the way down.

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  27. Not the mantle... by Radical+Moderate · · Score: 1

    Earth keeps its diamonds in the credenza.

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  28. high speed of sound, eh? by Anonymous Coward · · Score: 0

    Diamond Crystal Stabilized Oscillator, anyone?

  29. Diamonds... Diamonds!! by Anonymous Coward · · Score: 0
  30. Lucy by Anonymous Coward · · Score: 0

    So does this mean Lucy went to Hell?