Rainbow effect on minerals, oil on water, soap bubbles and other
examples comes from an optical effect in thin layers.
When light is reflected on a surface like a mirror it is reflected
equally in every wavelength and you don't get any effect. But if there
is a thin layer that some of the light is reflected from then you get
interference. If the extra distance travelled is equal to one or more
full wavelength of a colour then you get constructive interference and
that colour is enhanced. But if the distance travelled is equal to a
half plus zero or more full wavelength then you get destructive
interference and that colour is dampened.
The best example is a drop of oil on water where you could watch the
colours change while the oil layer gets thinner.
http://en.wikipedia.org/wiki/Thin-film_interference
My guess is that the colour seen on these meteorites comes from a thin
oxidation layer or maybe from oil from the hands that handled the
meteorite. Anyhow, you need a quite glossy surface to get that effect so
it is a really fresh meteorite.
Nice pictures!
/Göran
Martin Altmann skrev 2011-07-21 19:39:
Just some hours ago,
list-member Stephan Kambach sent me a picture of a Murchison individual,
showing such a rainbow effect.
Best!
Martin
-----Ursprüngliche Nachricht-----
Von: meteorite-list-boun...@meteoritecentral.com
[mailto:meteorite-list-boun...@meteoritecentral.com] Im Auftrag von Mike
Bandli
Gesendet: Donnerstag, 21. Juli 2011 19:21
An: 'Gary Fujihara'; 'Marc Fries'
Cc: meteorite-list@meteoritecentral.com
Betreff: Re: [meteorite-list] Rainbow Fusion crust
I've seen this "rainbow effect" in the fusion crust of a few specimens in my
life including Murchison, Ash Creek, and Buzzard Coulee. Jim Strope has a
great example of Murchison with this coloration in the crust here:
http://catchafallingstar.com/murchison723i.JPG
The complete page:
http://catchafallingstar.com/murchison723.htm
Very interesting. I would love to know what causes it.
----------------------------------------------
Mike Bandli
Historic Meteorites
www.HistoricMeteorites.com
and join us on Facebook:
www.facebook.com/Meteorites1
IMCA #5765
-----------------------------------------------
-----Original Message-----
From: meteorite-list-boun...@meteoritecentral.com
[mailto:meteorite-list-boun...@meteoritecentral.com] On Behalf Of Gary
Fujihara
Sent: Thursday, July 21, 2011 10:06 AM
To: Marc Fries
Cc: meteorite-list@meteoritecentral.com
Subject: Re: [meteorite-list] AD: Special: Truly baffling& sensational
Howardite - NWA 6709 - absolutely stunning and very fresh.
Great observation Marc. Iridescence is common on many pahoehoe lava flows
on the Big Island, and is quite remarkable to see.
Sent from Gary's iPhone
On Jul 21, 2011, at 6:53 AM, Marc Fries<mfri...@hotmail.com> wrote:
Mild oxidation of silicate glass (fusion crust in this case) can produce a
rainbow effect, too. I've seen this in basalts in the field. I think it is
from a sheen of iron oxides created as the iron and/or sulfide weathers out.
Cheers,
Marc Fries
On 7/21/11 1:13 AM, Aubrey Whymark wrote:
Hi
The rainbow colour looks like oil to me. Maybe someone has used oil or
WD40 to clean it. I sometimes encounter 'rainbow' tektites and the guys want
extra because of it - in reality it is due to oil contamination, probably
from the mining operations.
Regards, Aubrey
www.tektites.co.uk
--- On Thu, 21/7/11, Martin Altmann<altm...@meteorite-martin.de> wrote:
From: Martin Altmann<altm...@meteorite-martin.de>
Subject: Re: [meteorite-list] AD: Special: Truly baffling& sensational
Howardite - NWA 6709 - absolutely stunning and very fresh.
To: meteorite-list@meteoritecentral.com
Date: Thursday, 21 July, 2011, 0:33
Hi Mike,
no worries, neither we understood it like that.
Of course, if one looks to the photos, the first idea,
which comes to one's
mind is: oil.
No idea, what causes this effect, maybe the composition.
Also that strange
tint the cut faces reveal.
And especially worrying is the variety of the odd
inclusions. I mean
normally we all get already excited, whenever we find a
carbonaceous
fragment in a howardite,
but what that stone has all for strange clasts - that is
really not normal
anymore.
Since 1999 Stefan is in Morocco and since then we certainly
had quite a
bunch of materials in our hands,
but such a weird polymict one - extremely unusual.
And it seems that many collectors feel the same, if after
such a short time
now only three slices are left.
Now all of the smaller ones are gone, sorry for that. But
we have still a
slice left, which we could subdivide into small partslices,
if desired - but
for that one has really to raise his finger.
For the moment!
Martin
-----Ursprüngliche Nachricht-----
Von: meteorite-list-boun...@meteoritecentral.com
[mailto:meteorite-list-boun...@meteoritecentral.com]
Im Auftrag von Galactic
Stone& Ironworks
Gesendet: Donnerstag, 21. Juli 2011 00:48
An: Chladnis Heirs
Cc: meteorite-list@meteoritecentral.com
Betreff: Re: [meteorite-list] AD: Special: Truly baffling
& sensational
Howardite - NWA 6709 - absolutely stunning and very fresh.
Hi Martin,
I didn't mean to impeach the meteorite, I was just
curious.
This is indeed a mystery. Have any scientists offered
or agreed to
look at it? Perhaps hit the rainbow area with the
microprobe or SEM?
Aesthetically speaking, it's gorgeous and looks like Mother
of Pearl. :)
Best regards,
MikeG
--
----------------------------------------------------------------------------
-----
Galactic Stone& Ironworks - Meteorites& Amber
(Michael Gilmer)
Website - http://www.galactic-stone.com
Facebook - http://tinyurl.com/42h79my
News Feed - http://www.galactic-stone.com/rss/126516
Twitter - http://twitter.com/galacticstone
EOM - http://www.encyclopedia-of-meteorites.com/collection.aspx?id=1564
----------------------------------------------------------------------------
-----
On 7/20/11, Chladnis Heirs<n...@chladnis-heirs.com>
wrote:
No, it's natural!
Martin
-----Ursprüngliche Nachricht-----
Von: Galactic Stone& Ironworks [mailto:meteoritem...@gmail.com]
Gesendet: Mittwoch, 20. Juli 2011 23:24
An: Chladnis Heirs
Cc: meteorite-list@meteoritecentral.com
Betreff: Re: [meteorite-list] AD: Special: Truly
baffling& sensational
Howardite - NWA 6709 - absolutely stunning and very
fresh.
Wow! That is one of the most beautiful
howardites I have ever seen.
Nice find. :)
The rainbox coloration is very odd. Was the
stone cleaned at any time?
Best regards,
MikeG
----------------------------------------------------------------------------
-----
Galactic Stone& Ironworks - Meteorites&
Amber (Michael Gilmer)
Website - http://www.galactic-stone.com
Facebook - http://tinyurl.com/42h79my
News Feed - http://www.galactic-stone.com/rss/126516
Twitter - http://twitter.com/galacticstone
EOM - http://www.encyclopedia-of-meteorites.com/collection.aspx?id=1564
----------------------------------------------------------------------------
-----
On 7/20/11, Chladnis Heirs<n...@chladnis-heirs.com>
wrote:
Dear meteorite community,
with this Special we have to introduce to you an
enormous oddity.
It is about a HED-meteorite of a kind, which we
hadn't ever seen before
in
our careers before.
It came in two stones, one of them was covered
with a lush fusion crust,
wonderfully structured by thick and oriented
flowlines.
And in some parts, that very crust displayed a
gloss and a shine,
iridescent
in all colours of the rainbow;
an effect, reminding almost to bismuth!
Please take a look to the photos, where we tried
to captured the effect:
http://www.chladnis-heirs.com/new-meteorites/nwa6709.html
The interior was no less a riddle for us.
The distribution and sizes of the various
fragments and clasts were
unlike
we had seen in any polymict HED before.
A variety of clasts is of a kind, like we never
had recovered in any
Vesta
meteorite. Please take a closer look to the slices
and you will share our
surprise.
And a very few of these clasts develope due to
their microscopically
lamellae-texture a fire like an opal, if turned
around in the light.
The response to a magnet is very inhomogeneous
within the slices,
although no differences are visible to the eye
and all in all the interior has a somewhat dull
yellowish tint - although
the material is very fresh - and that tint and the
circumstances made us
initially think, it might be diogenitic.
It is under classification at Dr. Anthony Irving
and the values say, that
it
is a shocked howardite.
We crafted now a set of polished sliced of all
sizes, to share this
exceptional material with you.
Please acknowledge that we have kept the price,
despite of the for us so
unique properties of the material, well
affordable,
for everybody staying able to add a specimen of
this truly exceptional
stone
to his collection.
And an addition it is, also for the most
experienced veteran collector.
Earlier today we had published the Special in the
German forum, therefore
not so many specimens are left.
For the largest slice we can offer a discount as
it is the only one,
which
isn't coplanar.
And finally, the specimen named "piece #2", which
we chose to illustrate
best that rainbow-bismuth-gloss of the fusion
crust on the first linked
page, is available too. It weighs 119.2g and we're
accepting offers.
Here you are now:
http://www.chladnis-heirs.com/specials/special-nwa6709.html
Best Regards,
Stefan& Martin
Chladni's Heirs
Munich - Berlin
Fine Meteorites for Science& Collectors
http://www.chladnis-heirs.com
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