Identifying Gems and Minerals on Earth and Mars

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."
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Contact Information
Robert Downs, 520-626-8092,

M. Bonner Denton, 520-621-8246,

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/grou...php3?page=home

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

RRUFF Project
http://rruff.geo.arizona.edu