Hand-held Raman spectrometer.
For the field-oriented mineral collector and mineral show-goer who wants to have all the latest equipment (i.e. the best toys), there is now "The Rockhound," a portable hand-held device that promises to non-destructively identify minerals in the field by Raman spectroscopy analysis. This instrument is a spin-off of technology developed for NASA's Mars landers. Raman Spectroscopy is based on the Raman effect, which is the inelastic scattering of photons by molecules. The effect was discovered by the Indian physicist C. V. Raman in 1928. The Raman spectral signatures for different minerals tend to have sharp peaks that form a unique pattern, serving as "fingerprints" for each material.
The device weighs only 5 pounds and comes with a built-in library of 100 comparison spectra. Considering that there are over 4,000 mineral species, this is obviously a rudimentary database at best, but library development software is also supplied, allowing the user to load a much better database of mineral spectra for comparison with unknowns. Such a database has been prepared jointly by Robert Downs and Bonner Denton of the University of Arizona and George Rossman at Cal Tech; it can be accessed online at http://rruff.geo.arizona.edu/rruff/.
According to the promotional material, "This portable handheld unit is ideal for collectors because it can be taken to the field, clearance houses or exhibitions and specimens may be analyzed in only a few seconds." It even claims to identify (at least to a crude extent) cation mole fractions for [Ca.sup.+2], [Mg.sup.+2], and [Fe.sup.+2]. And an image of the specimen can be captured on the screen for future identification.
"The Rockhound" is produced by DeltaNu LLC, a manufacturer of chemical-sensing equipment based in Laramie, Wyoming. One of these handy little gadgets will set you back $18,500. (Check out the company's website at www.deltanu.com.) This is the first hand-held Raman analyzer to reach the market, and, as might be expected, it is expensive and, according to Downs, it still has a few bugs to be worked out; other models are expected to appear on the market by Christmas. Judging by the way technology usually progresses, I would expect that as the years go by the price will come down, the size of the device will be reduced, and its performance will be improved. Someday we'll probably be able to buy a pen-light-sized analyzer for $100 that announces the species name when you point it at a specimen!
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|Title Annotation:||notes from the EDITORS|
|Publication:||The Mineralogical Record|
|Date:||Nov 1, 2005|
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