[meteorite-list] do meteorites fluoresce??

[Jeff Grossman]

At 05:49 PM 2/28/2007, Mr EMan wrote:
>In the "for what its worth" category, the degree of
>fluorescence in feldspar chondrules is the means for
>defining the intermediate grades within the 3 grades,(
>e.g 3.1, 3.2 , etc.)  I don't know what wavelength is
>the standard for that examination.  If you've the
>fluorscent microscope and knowing those standards you
>might be able to observe this in common chondrite thin
>sections but I think it would be in some form we
>wouldn't easily recognize. A coverslip would of course
>block UV, but uncovered slides attract lint which
>glows brightly.

Actually, the property that is used to determine the petrologic types 
of chondrites is thermoluminescence (TL), not fluorescence.  TL is 
the emission of light in response to heating a sample, and it is a 
very small effect.  The fluorescence you are talking about is the 
emission of light after absorption of light of a different wavelength 
(often UV).

In point of fact, many meteorites do show a spectacular variety of 
luminescence, namely cathodoluminescence (CL).  This is emission of 
light in response to bombardment with an electron beam, as in 
CRTs.  Type 3 ordinary chondrites are particularly beautiful, with 
different minerals glowing red, blue, and yellow.  Check out the work 
of Derek Sears at: 
http://www.uark.edu/depts/cosmo/research%20projects/CL%20mosaics/
There are small, portable instruments that can be used to look at CL, 
but probably they won't be found outside of labs.

jeff


Dr. Jeffrey N. Grossman       phone: (703) 648-6184
US Geological Survey          fax:   (703) 648-6383
954 National Center
Reston, VA 20192, USA