[meteorite-list] black diamonds from Canyon Diablo

From: STARSANDSCOPES at aol.com <STARSANDSCOPES_at_meteoritecentral.com>
Date: Sat, 2 May 2009 18:30:11 EDT
Message-ID: <c96.3d089252.372e2373_at_aol.com>

Hi Laurence, Great paper! Thanks for sharing.

I had a related observation that I thought you might be able to shed some
light on.

The EL3 Enstatite NWA 2965 (and a whole lot more names/numbers) has small
graphite inclusions. I notice them most in the "Blue Phase". I have found
that these inclusions fool an electronic diamond tester. Other meteorite
graphite does not (At least what I have tried).

The grains are to small for me to resolve on my optical microscope, even
at a magnification of 1800X.

Is this likely just a fluke of the testing (Thermal conductivity), or are
there likely to be micro diamonds in the material at a level sufficient to
fool the tester?

The inclusions are soft and can be easily gouged out with a metal tool.

Thanks, Tom Phillips


In a message dated 5/2/2009 3:53:06 P.M. Mountain Daylight Time,
lgarvie at cox.net writes:
For those who are interested, my colleague and I recently worked on
the black diamonds from the Canyon Diablo meteorite. The abstract can
be downloaded at

www.lpi.usra.edu/meetings/lpsc2009/pdf/1346.pdf

In summary, they are not pure diamond but a combination of diamond,
lonsdaleite (hexagonal diamond), and graphite. We also found areas
that were neither diamond or lonsdaleite.



Laurence

-----------------------------------------------------------
Laurence A.J. Garvie
Collections Manager
Center for Meteorite Studies
School of Earth and Space Exploration
Arizona State University
Tempe
AZ 85287-1404
USA

phone: 480 965 3361
fax: 480 965 8102
email: lgarvie at asu.edu

Weblinks:
School of Earth and Space Exploration: http://sese.asu.edu/
Center for Meteorite Studies: http://meteorites.asu.edu/

-----------------------------------------------------------


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Received on Sat 02 May 2009 06:30:11 PM PDT