Tricorder identifies gems

Scientists are collaborating to develop a handheld spectroscopic device that can identify minerals on earth and other planets.

Robert Downs, associate professor of geosciences at The University of Arizona (UA), is working with M. Bonner Denton, a UA professor of chemistry and geosciences, to develop a pocket-sized Raman spectrometer to be used on the 2009 Mars rover. The technology being developed for Mars will help create handheld instruments for use on Earth.

“We’re developing a tricorder,” Downs said, referring to the Star Trek device used to analyse unknown materials.

One use for a hand-held instrument would be the identification of gemstones. 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. Raman spectroscopy is a non-destructive alternative.

A Raman spectrometer fires 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. The material is identified by comparing it with reference information from a database.

Downs is collaborating with George Rossman of the California Institute of Technology to develop a comprehensive database of minerals to be used with the tool. So far the project has catalogued about 1,500 of the approximately 4,000 known minerals. The effort is known as the RRUFF Project.