[meteorite-list] Identifying Gems and Minerals on Earth and Mars

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Mar 9 19:58:10 2006
Message-ID: <200603100056.k2A0uNi07349_at_zagami.jpl.nasa.gov>

IDENTIFYING GEMS AND MINERALS ON EARTH AND MARS
(From Mari N. Jensen, UA Office of University Communications, 520-626-9635)

- Thursday, March 9, 2006
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Contact information is at the end of this release.
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It'll be a snap to identify gemstones once Robert Downs finishes his library
of spectral fingerprints for all the Earth's minerals.

Downs is almost halfway there. So far, the associate professor of
geosciences at The University of Arizona in Tucson has cataloged about 1,500
of the approximately 4,000 known minerals using a technique called Raman
spectroscopy. The effort is known as the RRUFF Project.

"We're developing a tricorder," Downs said, referring to the instrument used
on the "Star Trek" television show that could be waved over materials to
identify their chemical composition.

Downs' work is destined for space. Although Downs' current Raman
spectrometer takes up an area the size of a tabletop, his colleague M.
Bonner Denton, a UA professor of chemistry and of geosciences, is developing
a pocket-sized Raman spectrometer to be used on the 2009 Mars rover.

Downs is collaborating with George Rossman of the California Institute of
Technology in Pasadena to develop the database of minerals.

The technology being developed for Mars will help create handheld
instruments for use on Earth.

One use for a hand-held instrument would be the identification of gemstones.
Downs and Denton will both give presentations on that aspect of the project
on Sunday afternoon, March 12, at the 57th Annual Pittsburgh Conference on
Analytical Chemistry and Applied Spectroscopy (PITTCON 2006). More details
about their presentations are at the bottom of this release.

Other ways to accurately identify minerals, such as X-ray diffraction and
electron microprobe, require grinding a bit of the sample to powder or
polishing the sample in a specific manner.

However, such rough treatment may not be the method of choice to determine
that a glittering gemstone is truly a diamond, rather than just a piece of
cubic zirconia.

Unlike other methods of identifying minerals, a Raman spectrometer does not
require destructive sampling. It shoots a laser beam at the sample. The
laser excites atoms within the sample, which then emit a very weak light of
a wavelength in a pattern characteristic of the material.

"It's like a fingerprint," Downs said.

The technique is named after Sir C.V. Raman, who won a 1930 Nobel Prize for
figuring out the underlying physics.

But no Raman spectrometer, big or small, can conclusively identify Mars
rocks or any other kinds of minerals without the kind of comprehensive
database Downs is creating.

When an unknown material is analyzed with a Raman spectrometer, it can be
identified by comparing it with reference information from a database.

In Downs' lab, a small army of undergraduate researchers is helping complete
the RRUFF Project, the first comprehensive database containing the Raman
spectra of all the Earth's minerals.

The RRUFF project is supported by funding from gemstone connoisseur and
collector Michael Scott, founding president of Apple Computer. Scott has a
degree in physics from the California Institute of Technology. RRUFF is the
name of Scott's cat.

NASA provided funding to develop the instrument for the 2009 Mars Rover.

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Presentation titles, times and locations:
Denton and Downs' presentations will be part of the symposium,
"Gemstone/Mineral Analysis: Developing Non-Destructive Analytical Methods
and Assessment Standards for Identification and Classification," held in
room 222A of the Orange County Convention Center in Orlando, Fla.

Denton's 2:55 p.m. presentation, "The Present and Future Potential of Raman
Spectroscopy in the Characterization of Gems and Minerals," will be followed
at 3:15 p.m. by Downs' presentation, "The RRUFF Project: Creating an
Integrated Database of Oriented Raman Spectra, X-Ray Diffraction and
Electron Microprobe Analyses of Minerals."
-----------------------------------------

Contact Information
Robert Downs, 520-626-8092, downs_at_geo.arizona.edu

M. Bonner Denton, 520-621-8246, mbdenton_at_u.arizona.edu

Conference Press Room
Room 307CD, Orange County Convention Center, Orlando, Fla.
407-685-4092
March 12, 10 a.m. - 5 p.m.
March 13-15, 7:30 a.m. - 5 p.m.
March 16, 7:30 a.m. - 3 p.m.

Related Web sites:
Robert T. Downs
http://www.geo.arizona.edu/xtal/group/index.php3?page=home

M. Bonner Denton
http://www.chem.arizona.edu/faculty/profile/profile.php?fid_call=dent

RRUFF Project
http://rruff.geo.arizona.edu
Received on Thu 09 Mar 2006 07:56:23 PM PST