Forensic experts profile gemstones

APRIL 12, 2005 - New Orleans -- Findings presented at a recent American Academy of Forensic Sciences (AAFS) reveal a new way to map the profile of individual gemstones. The new technique, called "microspectrometry," allows mapping of each stone's color patterns.

Paul Martin, president of California-based company CRAIC Technologies, which analyzes forensic data gathered from crime scenes, told CNN International that changes in light cause changes in the gemstone color. Mapping the variations in color will enable jewelers to spot a gem's type and quality, including whether it is a synthetic. It could also help with identifying stolen gems, Martin said.

Jewelers and scientists say each gemstone is unique, but until recently, proving this had been difficult. The new techniques, announced at last month's AAFS meeting in New Orleans, analyze wavelengths of light emitted by a 10-micrometer point on the surface of individual stones, producing an individual spectrum for that particular stone.

George Rossman, a mineralogist at the California Institute of Technology, was skeptical of the claim that every gem's spectrum was different, according to CNN. But he acknowledged that mapping variations in color could provide useful information.

"The question that needs to be researched is whether this tool adds enough to what is out there already," he said.