[meteorite-list] [Fwd: Re: Ultraviolet Space Rocks]

From: David Gunning <davidgunning_at_meteoritecentral.com>
Date: Mon, 4 Oct 2010 07:30:57 -0400 (EDT)
Message-ID: <1319.69.50.53.154.1286191857.squirrel_at_webmail.fairpoint.net>

--------------------------- Original Message ----------------------------
Subject: Re: [meteorite-list] Ultraviolet Space Rocks
From: "David Gunning" <davidgunning at fairpoint.net>
Date: Mon, October 4, 2010 7:28 am
To: edeckert at triad.rr.com
-------------------------------------------------------------------------


Excellent point, there, Ed. Wouldn't it be useful information if those
meteorite cutters out there were considerate enough to mention their
cutting lubricant medium at the point of sale? Concerning the idea that
there may be a degree of comfortability by being able to predict a
particular cutting fluid's response on a given specimen, maybe. But,
then, part of the fun and allure of fluorescent mineral testing may be
associated with the notion that unexpected results and unusual UV colors
can occasionally rear their lovely faces and sometimes be as quite and
totally unexpected as they were unpredictable!

I've got a collection of diamond crystals I dug in Arkansas that show a
range of fluorescent color values, particularly with midrange UV, that
were as totally unexpected and immensely enjoyable to look at as they are
considered rare and unheard of in diamond collecting circles.

Yours for the light!

Dave Gunning


>
> 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 Mon 04 Oct 2010 07:30:57 AM PDT