[meteorite-list] Meteorite Yields Carbon Crystals Harder Than Diamond

From: Steve Dunklee <steve.dunklee_at_meteoritecentral.com>
Date: Wed, 3 Feb 2010 23:34:44 -0800 (PST)
Message-ID: <968783.98967.qm_at_web113917.mail.gq1.yahoo.com>

I may be wrong but seems to me the pressures of entering the atmosphere did not create the diamonds unless they were in the crust. A supernova on the other hand is a more likely source of them.
cheers
Steve

--- On Thu, 2/4/10, STARSANDSCOPES at aol.com <STARSANDSCOPES at aol.com> wrote:

> From: STARSANDSCOPES at aol.com <STARSANDSCOPES at aol.com>
> Subject: Re: [meteorite-list] Meteorite Yields Carbon Crystals Harder Than Diamond
> To: meteorite-list at meteoritecentral.com
> Date: Thursday, February 4, 2010, 2:24 AM
>
> Hi list,? This is off topic (sort of)? to?
> this very interesting post but
> it
> does mention graphite and?
> diamonds.???
>
> I have shared this observation before and every? time
> I have mentioned it?
> I
> have been taken wrong!? Has any else? noticed how
> the graphite inclusions?
> in the fossil EL3, NWA 2828, 2965,? Al Haggounia 001
> etc. fool an
> electronic?
> diamond tester?
>
> Now? this is the part I have been taken wrong on, I'm
> not? saying I have?
> found testable size diamonds but rather the graphite will
> set off? an?
> electronic diamond tester!? Those testers operate on
> thermal???
> conductivity.?
>
> I can take my optical scopes to 2000X but that is?
> no? help in this stuff.
>
> I have tried similar inclusions in other?
> meteorites? and nothing.? Is the
> inclusion made of nano diamonds? or just a
> material? that is as thermally
> conductive as? diamonds????Which ever,
> it is? interesting!
>
> Tom? Phillips
>
> In a message dated 2/3/2010 6:23:57 P.M. Mountain Standard
> Time,? baalke
> _at_zagami.jpl.nasa.gov? writes:
>
> http://www.physorg.com/news184402061.html?
> ???
>
> Meteorite yields carbon crystals harder than diamond
> by Lin? Edwards
> physorg.com
> February 3, 2010
>
> (PhysOrg.com) -- Two new? types of ultra-hard carbon
> crystals have been
> found by researchers? investigating the ureilite class
> Haver? meteorite
> that crashed to Earth in? Finland in 1971. Ureilite
> meteorites are
> carbon-rich and known to contain? graphite and
> diamonds.
>
> The super-hard diamonds were created when graphite? in
> the meteorite
> experienced the intense heat and pressure of entering
> the? Earth's
> atmosphere and crashing into the ground. The graphite
> layers would?
> have been heated and shocked enough to create bonds between
> them, in?
> much the same way as humans manufacture
> diamonds.
>
> The new carbon? crystals were too small to test for
> precise hardness but
> they are known to be? harder than normal diamonds
> because the researchers
> found them by using a? diamond paste to polish a slice
> of the meteorite.
> The crystals were raised? more than 10 ?m above the
> polished surface,
> which meant they were harder than? the diamonds in the
> polishing paste.
> The researchers had seen carbon crystals? that
> resisted the diamond
> polishing in one direction before, but the new?
> crystals were unaffected
> when polished in every direction.
>
> The? scientists then used an array of mineralogical
> instruments,
> including? microscopy, spectroscopy and
> energy-dispersive X-rays among
> others, to study? the structure of the crystals. This
> allowed them to
> identify them as? representing two new carbon
> polymorphs or diamond
> polytypes.
>
> One is an? ultra-hard rhombohedral carbon polymorph
> similar to diamond,
> while the other? is a 21R diamond polytype ultra-hard
> diamond. The
> existence of ultra-hard? diamonds had been predicted
> decades ago, but
> they have never before been? found in nature. The
> novel form consists of
> fused graphite sheets similar to? artificial diamond.
>
> Professor Tristan Ferroir, leader of the research?
> team from the
> Universit? de Lyon in France, said the discovery was?
> accidental, but
> they had thought an examination of the meteorite would
> "lead? to new
> findings on the carbon system."
>
> Professor Ferroir said there is? currently no way to
> compare the
> structure of the new crystals to boron? nitride and
> lonsdaleite, the
> artificially manufactured ultra-hard diamonds,? but
> the findings help
> scientists gain a better understanding of carbon?
> polymorphs and give
> them new materials to investigate and perhaps?
> synthesize. They also
> show the carbon system is more complex than
> previously? thought.
>
> The findings on the new diamond were published in the
> Earth? and
> Planetary Science Letters journal on February 15.
>
> More? information:*? http://dx.doi.org/10.1016/j.epsl.2009.12.015
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Received on Thu 04 Feb 2010 02:34:44 AM PST