FMF - Friends of Minerals Forum, discussion and message board

[Jbcourt]

Could there be very large Diamonds inside earth? When I say big I mean 100,000 Carats or more. Is it posible that diamonds we find near the surface today are merely just pieces from larger diamonds that were shattered to bits during faulting or volcanic events?

[Pete Richards]

[Jason]

I believe there are much larger diamonds in the interior. Nothing stops the formation of how big a diamond can get down in the vicious interior except for amount of carbon present(if conditions like temp. and kilobars is correct). What would, would be it's rapid ascent from from 80 miles down. Studies say kimberlite material travels at an upwards rate faster than the speed of sound..thats 768 miles an hour! take any diamond and throw it at another rock or concrete at 700 miles an hour and you will get a busted diamond. Lots of little pieces. Small diamonds have less mass so are less susceptible to busting which is why you find many nicely formed crystals. Stand 10 feet from a concrete wall and throw a 1ct diamond at it as hard as you can and chances are it will bounce off with maybe a chip. Throw a 1000ct diamond at it and chances are it will bust up into a few pieces. Thats why all the largest diamonds found are not nice octahedrals but more like chunks. We all know the story of the Cullnian:

"The stone possessed a surprisingly smooth cleavage face on one side, leading many experts to believe that the huge stone was only a piece of a larger diamond that was broken up in the process"

Diamond or not..travel 700 miles and hour for over 80+ miles through all kinds of hellish conditions and you will get all busted up, especially if you have a good deal of mass. I believe diamonds get as big as basketballs in the earth's interior..give or take.

[Pete Modreski]

That's certainly an intriguing question, about how large the diamonds may be.

I have personally seen, in the Larimer County, Colorado kimberlite pipes, xenocrysts of chrome diopside about 9 cm across, and enstatite at least 5 x 10 cm; and a pyrope crystal up to 12 cm and weighing over 2 pounds was reported there. I'm sure that even larger examples of all these minerals have been found worldwide. Of course, these rock-forming minerals associated with diamond are much more abundant in the mantle than the diamonds themselves are, so they may have more opportunity to form large crystals.

It seems like there is some, but not a great deal, evidence for diamonds being broken during emplacement. I personally tend to think that the "supersonic rate of ascent" of kimberlites is something that is a bit overstated. That may be true for the final few km or tens of km once a gas-rich kimberlite has vented to the surface, but some kimberlites are intrusive and have never reached the surface.

But of course, any who have seen the 2003 movie The Core know that there are big diamonds down in the mantle, because it showed their manned* probe boring through the mantle, making evasive maneuvers to dodge the giant diamond crystals their imaging system showed in its path! [I should rather say "crewed" instead of "manned", since Hilary Swank was the captain.]

Cheers, Pete

[Les Presmyk]

This is an interesting thread if you want to discuss philosophy, faith and conjecture. While I do not wish to dissuade Jason's search for information, everything he writes starts with these two words "I believe". It appears he is looking for someone to say "I agree" and lend credence to his belief.

[Jason]

Not really sure what to make of your post Les????
The phrase "I believe" means from all the available evidence it has come to my conclusion that there are. No way of testing it myself or going down 80 miles into the earths interior. Plus this quote I pulled about the Cullnian diamond says "many experts believe"
Don't know who the experts are but they "believe" also. :)
""The stone possessed a surprisingly smooth cleavage face on one side, leading many experts to believe that the huge stone was only a piece of a larger diamond that was broken up in the process"

[Jbcourt]

Thank you Pete for helping me think this through more. I should of relized that faulting may not be posible at those depths.