[meteorite-list] Ultraviolet Space Rocks

From: edeckert at triad.rr.com <edeckert_at_meteoritecentral.com>
Date: Sun, 3 Oct 2010 22:59:55 -0400
Message-ID: <20101004025955.D7LVY.141474.root_at_cdptpa-web28-z02>

Hi David, Dr. Garvie, and the list,

I am having email and PC issues, so I am not sure if my prior attempts to compose this message disappeared - or went out. So please forgive any duplicate messages. I am also unsure if anyone else may have made the comment I am making as my email problems have resulted in lost emails.

It may be worthy to note that one may see a "false" fluorescence in any specimen - meteorite or terrestrial rock - if it was sliced using certain cutting fluids. Some cutting fluids will fluoresce under UV light, and if they soak into the specimen being cut, it can lead you to believe that piece is indeed fluorescent.

I want to clarify that I am not referring to Dr. Garvie's specimen when I mention this. I mention this as a caveat to list members who may now be interested in checking the sliced specimens in their collection for fluorescence.

If you cut it yourself, all you need do is check your cutting fluid for fluorescence. Purchased specimens are not going to be as easy to validate, but not impossible. If the color and intensity of the fluorescence agrees with the expected results of the mineral present, under the correct UV wavelength, then you should be able to validate it. Manuel Robbins' books are a great resource for UV mineral information.

Ed


---- David Gunning <davidgunning at fairpoint.net> wrote:
>
> Hi Laurence Garvie,
>
> Thanks for filling-in some of the missing pieces of the minor puzzle
> concerning your fascinating "Rocks from Space Picture" dated September
> 29, 2009.
>
> Trace amounts of manganese (Mn) may certainly play a contributing if not
> dominant role in explain the yellow colored fluorescence, as I understand
> these things. That may not be, however, the entire story. According to
> author Manual Robbins (FLUORESCENCE: Gems and Minerals Under Ultraviolet
> light, 1994, Geoscience Press, Inc., Phoenix, Arizona), there may be some
> sort of structural defect within the crystal structure, itself, which may
> and can play a role in contributing to the fluorescence, also.
>
> Wollastonite, from Franklin, New Jersey, fluoresces a brilliant yellow
> color due to trace amounts of Mn, less than 0.1 percent. Lead, also, may
> act as a co-activator in the wollasonite helping to provide absorption of
> ultraviolet, according to Robbins.
>
> Concerning your picture, again, for a moment. I'm curious if you exposed
> your space rock to the two other main wavelengths of ultraviolet, UVB, or
> medium wave at 315nm-280nm, or UVC shortwave at 280nm-100nm?
>
> Still scratching my noggin over those secondary blue/green UV colors that
> appear in your fascinating picture.
>
> Any additional thoughts that might help explain that apparent UV color
> phenomena?
>
> Thanks for your time.
>
> Dave Gunning
>
>
>
>
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Received on Sun 03 Oct 2010 10:59:55 PM PDT