[meteorite-list] Fw: MOLDAVITE COLORS

[Sterling K. Webb]

I'm assuming that Tomek does not mind my
forwarding his email to the List. If Norm
Lehrman says it ain't a tektite... it ain't a
tektite! I rather imagine that's who Bob
would check a tektite with.  I certainly
would.

I took the reference to it from Guy Heinen's
book, which was published in 1998, probably
well before the true identity of the yellow
"moldavite" was known.

I posted this once before, but it fits here:
One of the best sources for extensive information about
any resource unique to (mostly) one country is that
county's Geological Survey, in this case this:
http://www.geology.cz/bulletin/contents/2002/vol77no4/04trnkafinal.pdf
It's Everything You Ever Wanted To Know About
Moldavites But Were Afraid To Ask...

And this:
http://www.geology.cz/bulletin/contents/2002/vol77no4/05artemievafinal.pdf
And... Wait! There's a whole page of these things.

Just go to:
http://www.geology.cz/
and browse for publications (they're mostly in English).
Or Google "Czech Geological Survey" and expand
the results.


Sterling K. Webb
------------------------------------------------------------------------------
----- Original Message ----- 
From: "tomasir" <TomekOglaza at poczta.fm>
To: "Sterling K. Webb" <sterling_k_webb at sbcglobal.net>
Sent: Friday, December 10, 2010 3:31 PM
Subject: Re: [meteorite-list] MOLDAVITE COLORS


Hello,

regarding Robert's yellow moldavite:

Also, Robert Haag has a celebrated yellow 'moldavite' that is "right" in 
every (visual) aspect except tektitic origin---- it is man-made ancient 
glass.


Not sure whether it is true or not (source: 
http://www.tektitesource.com/Tektite_tests.html )

regards
tomasir

Uzytkownik  napisal(a):
> From:
> Subject: Re: [meteorite-list] MOLDAVITE COLORS
> To: meteorite-list at meteoritecentral.com;
>
> Hi, List, and Mike Gilmer who asked originally,
>
> Yes, Mike, it is the iron.
>
> Moldavites are high in Si02, usually close to
> 80%. that is, they have a higher "glass" content
> and fewer "minerals." The most common other
> ingredient is Al203, from 8% to 10%. Fe0 makes
> up only 1% to 2%, and it is this iron-poor recipe
> that makes them green and gem-like.
>
> Moldavites range in color from a very pale green
> to a brown that can be as dark as a light Indochinite.
> The color is determined by an increase in the ratio
> of trivalent iron over bivalent iron over the range of the
> green-to-brown spectrum. The index of refraction and
> the density increases in the same way.
>
> Almost every type of splash-form known from the
> Australo-Asian strewnfield are found in moldavites
> as well, but "drops" and "dumbbells" are rare. There
> are Muong-Nong moldavites found in the Budejovice
> region, but no aerodynamic buttons have ever been
> found.
>
> Moldavites have many forms unique to them, like the
> "leaf" type. Moldavites frequently contain trains of
> gas bubbles, Occasionally, a two-colored moldavite
> is found, formed when two plastic moldavites collided
> in flight and stuck together. And Bog Haag has the
> one and only known YELLOW one.
>
> And while I typed this and checked the figures, the
> question was answered already...
>
>
> Sterling K. Webb
> --------------------------------------------------------------------
> ----- Original Message ----- 
> From: "Chris Spratt"
> To:
> Sent: Friday, December 10, 2010 12:15 PM
> Subject: Re: [meteorite-list] Mineral responsible for green color
> inMoldavite?
>
>
> >I think it may be a form of Beryilium or Beryl.
> >
> > Chris. Spratt
> > Victoria, BC
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