[Rockhounds] when volcanoes drop bombs: giant crystal payload

[Axel Emmermann]

Alan,

I think that the diamonds don't actually travel to the surface. They stay
kilometers deep under high pressure and temperature. Slow crystallization
and annealing over long time periods is what makes good diamonds.
Erosion and geological activity bring them closer to the surface. At least,
if the info in the Antwerp diamond museum is correct ;-)))
Not entirely sure but rather pretty sure.

Axel

> -----Oorspronkelijk bericht-----
> Van: rockhounds-bounces at lists.drizzle.com 
> [mailto:rockhounds-bounces at lists.drizzle.com] Namens J Bryan Kramer
> Verzonden: woensdag 22 augustus 2007 13:52
> Aan: Rockhounds at drizzle.com: A mailing list for rock and gem 
> collectors
> Onderwerp: Re: [Rockhounds] when volcanoes drop bombs: giant 
> crystal payload
> 
> It takes very special conditions for diamonds to survive the 
> trip to the surface. This occurs in structures called 
> Kimberlite Pipes, but not all of them have diamonds:
> 
> <http://en.wikipedia.org/wiki/Kimberlite>
> 
> The diamonds are pushed up to the surface at supersonic 
> speeds from far below the surface, maybe 100 miles deep or 
> more. There is a very interesting book on the search for 
> diamonds in North America, The Barren Lands:
> 
> <http://www.amazon.com/Barren-Lands-Search-Diamonds-American/d
p/0805071857/ref=pd_bbs_sr_1/002-1480255-9384004?ie=UTF8>
&s=books&qid=1187786960&sr=8-1>
> 
> It is well worth $12 or you may be able to find it at your 
> library. It is a good readable book.
> 
> BK
> 
> On 8/21/07, teresa jetter <territoones1 at ameritech.net> wrote:
> > Hi Kitty,
> >   Can you answer me a question please.  I understand that when a 
> > volcano erupts and the magma flows up and out, Diamonds are 
> created?  
> > Is this true?
> > I have read on the subject, but I have never really tried 
> looking for 
> > any such Diamonds.
> > Just a question I thought you, or someone could answer for me.
> > Teri Jetter- Ohio
> > --- Kitty & Bill Heacox <kahako at hawaiiantel.net>
> > wrote:
> >
> > > Agreed, cool stories.
> > >
> > > BTW, Pete you should override your spellchecker so it 
> will leave Mr.
> > > Emmermann's given name as Axel, not Alex!  ;)
> > >
> > > Aloha,Kitty
> > >
> > > At 02:26 AM 8/1/2007, you wrote:
> > > >Cool stories, Alex and Don, and that's a great
> > > photo of the glassy feldspar
> > > >crystal in the volcanic bomb from Spencer ID.
> > > >
> > > >I should try to guess what it is; I'm torn between
> > > guessing orthoclase or
> > > >sanidine; I'll go with orthoclase.  Let me know
> > > what it turns out to  be.
> > > >
> > > >And I hate to sound like the skeptic, but I cannot
> > > believe that any  feldspar
> > > >crystal like this (or the one you describe, Alex)
> > > actually "grows"  inside
> > > >the cooling volcanic bomb, no matter what Alex's volcanologist  
> > > >friend thinks he might have seen on Vanuatu.  I think Don will
> > > agree--that  just ain't
> > > >possible.  Those crystals are "megacrysts", also
> > > could be
> > > >called  "xenocrysts".  They
> > > >grew somewhere else when the magma was still deep
> > > down,  10s of kilometers
> > > >deep, and then they were carried up by the magma
> > > and encased  by a glob of it
> > > >when it was erupted.  Any crystal growth while
> > > embedded in  that
> > > >rapidly cooling
> > > >lava bomb would have been very very minor, on a
> > > microscopic  level along the
> > > >very surface edges of the megacryst.
> > > >
> > > >Pete Modreski
> > > >
> > > >
> > > >
> > > >************************************** Get a sneak
> > > peek of the all-new AOL at
> > > >http://discover.aol.com/memed/aolcom30tour
> > > >
> > > >
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> 
> --
> J Bryan Kramer
> North Florida, USA
> photos at:
> http://pbase.com/photoburner
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