[meteorite-list] Simple Tektite Test

From: N Lehrman <nlehrman_at_meteoritecentral.com>
Date: Thu Apr 22 09:53:36 2004
Message-ID: <004801c2a8c6$8f1f9d80$19e3fea9_at_homeportal.2wire.net>

Bob and list,

Thanks for the references to earlier discussions. I'll try to catch up on
the good stuff I've missed. I would, however, challenge the transmitted
light coloration standard. If all the world's recognized tektites were
australasians, Ivory Coasts, and bediasites, and someone brought in a
moldavite, what would the standard dictate? And the golden caramel of a
Georgiaite? How about Libyan Desert Glass? We suppose LDG is an impactite
rather than a tektite, but by what standard of reference? Lack of brown
color? We're looking for a standard to measure something NEW.

Currently the Amerikanite/Colombianite/"Arizonaite" issue keeps resurfacing.
I would instantly grant that most of this material is terrestrial obsidian.
BUT I do also endeavor to examine my own cherished "truths" fairly and
cynically. There was this one time that I was wrong. There are two issues
that haunt the corners of my mind: skin ornamentation and transmitted light
color.

I am an exploration geologist and I have spent 30 years in the field in
every continent except Africa and Antarctica. I have never seen (volcanic)
obsidian with the peculiar violet/lavender hues of Amerikanites. On our
website Amerikanite/Colombianite page (TektiteSource.com) , I have pictured
Colombianite skin textures with lizard-skin beading and U-shaped grooving
that I have yet to observe in volcanic settings but have seen in bona fide
tektites.

Do understand that I am entirely neutral as to whether Colombianites (or any
other suspect glass) is or is not a true tektite. But I do want to give new
discoveries a fair hearing. Hence the quest for differentiating standards.

Like you metioriteophiles, us tektite people get bombarded with Wannabes
that we're supposed to certify or kill. But beyond that, I want a general
basis for assuming a posture on Colombianites and their kin. I would love
to be able to say that they ABSOLUTELY are or are not tektites (and I don't
care which way it goes so long as it's objective and unbiased).

Please forgive me if I am repeating previously debated questions. Insofar
as I work ten days out in the field and a day or two back during the field
season, I have to interrupt meteorite-list mail until the winter grants me
time at home. I'm probably not the only guy out here that benefits from
repetition, so bear with us!

Cheers,

Norm


----- Original Message -----
From: "Robert Verish" <bolidechaser_at_yahoo.com>
To: "Meteorite-list Meteoritecentral" <meteorite-list_at_meteoritecentral.com>
Sent: Friday, December 20, 2002 8:50 PM
Subject: [meteorite-list] Simple Tektite Test


> The last time we discussed this thread was only 3
> months ago - go to the URL below and scroll down to
> Wed, 25 Sep 2002:
>
> http://www.pairlist.net/pipermail/meteorite-list/2002-September/date.html
>
> There was quite a lot discussed about all of this. I
> think the general consesus was that - although there
> are MANY kinds of tests to differentiate tektites from
> obsidian - there was NO "simple test".
>
> There was always some darn "exception to any rule"
> that we tried to formulate.
>
> -------------------------------------
> Did the following in about 20 seconds:
>
> Searched the web for "tektite glass verish".
>
> Results 1 - 5 of about 16. Search took 0.10 seconds.
>
> Mail Thread Index
> ... Re: Glass bombs impactite or tektite, Bernd Pauli
> HD. Re ... glass bombs, Guy Heinen;
> OUR TEARS AND LOVE GO OUT TO ... RE: Search meteorites
> on Mars, Verish, Robert S. Fw ...
>
> http://www7.pair.com/arthur/meteor/archive/archive7/March99/threads.html
>
>
> Mail Index
> ... From: "goldmaster" <goldmaster_at_gci-net.com>.
> Re: Glass bombs impactite or tektite: ...
> futrelds_at_gte.net>.
> RE: Search meteorites on Mars: From: "Verish,
> Robert S ...
>
> http://www7.pair.com/arthur/meteor/archive/archive7/March99/maillist.html
>
>
> [ More results from www7.pair.com ]
>
> [meteorite-list] Re: TEKTITES!! ....METEORITES OR JUST
> GLASS ??? ...
> ... METEORITES OR JUST GLASS ???? ... Robert Verish
> bolidechaser_at_yahoo.com Wed, 25 Sep 2002
> 12 ... Wednesday 9/25; Next message: [meteorite-list]
> Tektite color transmission; ...
>
>
http://www.pairlist.net/pipermail/meteorite-list/2002-September/014824.html
>
>
> http://www.pairlist.net/pipermail/meteorite-list/2001-April.txt
>
>
> ---------------- Attached Message ---------------
>
>
http://www.pairlist.net/pipermail/meteorite-list/2002-September/014824.html
>
> [meteorite-list] Re: TEKTITES!! ....METEORITES OR JUST
> GLASS ???? Discuss..........
> Robert Verish bolidechaser_at_yahoo.com
> Wed, 25 Sep 2002 12:00:42 -0700 (PDT)
>
> --------- Original Message -----------
> [meteorite-list]
> Re: TEKTITES!! ..METEORITES OR JUST GLASS ??
> Discuss...
> thornysahuaro thornysahuaro_at_yahoo.com
> <mailto:thornysahuaro%40yahoo.com>
> Tue, 24 Sep 2002 21:25:23 -0700 (PDT)
>
> Greetings all,
> Would any of you please explain the differences
> between Tektites and Apache Tears. Apache Tears are
> rounded bits of smokey grey obsidian (volcanic glass)
> found all over the Southwest US. They have a dull
> black surface and often have perfect regmaglypts when
> found.
> To me this would indicate that they were ejected quite
> high before they fell. When POLISHED they range from
> nearly opaque black to a nearly clear light gray
> color. Some have lines or swirls of darker glass that
> can be seen if held up to a light.
> Thanks,
> Art Brasher
> -------------------------
>
> Hello Art,
>
> You came very close to answering your own question.
> Your last line describes how an "Apache Tear" looks
> when "held up to a light". And you made reference
> to its "gray color".
> Now, if you hold a tektite up to that same light, you
> will notice that it is distinctively BROWNISH in
> color. [With the obvious exception of some
> Moldavites]
>
> Please note that we are describing the color of
> TRANSMITTED light THROUGH obsidian and tektites.
>
> I believe this is the distinguishing characteristic
> that collectors are looking for, particularly when
> they are at a show and are trying to decide on a
> purchase.
> The quick test is to pull out a pocket flashlight and
> place the specimen over the light bulb. Tektites will
> be some shade of brown (even the black opaque ones
> will still show some brown coloration along their
> thinnest edges). If there is no shade of brown
> whatsoever, but instead a gray to purplish-gray, then
> its obsidian!
> And that's a fact!
> And I'm sorry if your Americanite, or Bediasite, or
> Columbiaite doesn't show any of this brown color, but
> there has been a lot of Safford Arizona obsidianite
> look-a-likes [AZites] getting into the Tektite market.
>
> I have to thank the late-Darryl Futrell for showing me
> this quick diagnostic trick.
> I had taken some suspect "American tektites" to Darryl
> for his examination. And within seconds, he turned
> thumbs-down on these specimens. He allowed me to use
> this technique on all of the various types of tektites
> in his collection, and every variety would show in
> transmitted light some shade of brown, gold, or
> yellowish-green.
>
> I have yet to find a variety of obsidian that would
> transmit any brownish color. [UPDATE - I now know of
> at least 4 varieties from North America.)
> They are [almost] always gray to purplish-gray in
> transmitted light.
>
> Bob V.
>
> ----------- End of Attached Message ------------
>
>
>
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Received on Sat 21 Dec 2002 02:57:07 AM PST