[meteorite-list] Re: TEKTITES!! ....METEORITES OR JUST GLASS ???? Discuss..........

From: Robert Verish <bolidechaser_at_meteoritecentral.com>
Date: Thu Apr 22 10:08:31 2004
Message-ID: <20020925190042.97624.qmail_at_web80313.mail.yahoo.com>

--------- 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.
They are always gray to purplish-gray in transmitted
light.

Bob V.



__________________________________________________
Do you Yahoo!?
New DSL Internet Access from SBC & Yahoo!
http://sbc.yahoo.com
Received on Wed 25 Sep 2002 03:00:42 PM PDT