SSEF Introduces LIBS to Gem Industry Labs
By Gary Roskin, G.G., FGA, Senior Editor -- JCK-Jewelers Circular Keystone, 7/1/2004
As mentioned last month, Dr. Henry Hänni of the Swiss Gemmological Institute (SSEF) is now offering inexpensive identification of beryllium-diffused corundum. This breakthrough was the result of Hänni's adapting a qualitative laser spectrometer for a process called laser-induced breakdown spectroscopy, or LIBS.
Previously, beryllium detection had used quantitative methods employing micro mass spectrometry, such as laser ablation (LA-ICP-MS) or secondary ion mass spectroscopy (SIMS), technologies that are costly and not always available to professional gem labs.
LIBS allows SSEF to offer affordable trace elemental analysis of gemstones. Representatives of GIA's Gem Trade Lab and the American Gem Trade Association's Gem Testing Center laboratory have said that they too will use this technology.
Hänni explains how it works: "The single laser pulse transforms some micrograms of the gemstone sample into a plasma, which is then examined using a spectroscope, to detect identifying spectra. Almost all chemical elements are detectable, including, of course, beryllium. A quantitative analysis is possible when reference samples are used whose contents have been determined previously by LA-ICP-MS or SIMS."
All three methods are slightly destructive. Very small burned spots—often referred to in greatly exaggerated fashion by laboratory gemologists as "craters"—remain after a laser shot.
SSEF also plans to help other labs by offering GemLIBS training, GemLIBS instruments (a package including GemLIBS standards, GemLIBS sample holder, GemLIBS sample stage, and GemLIBS training), and GemLIBS standard materials for quantification of LIBS spectra.
For more details, contact SSEF at gemlab@ssef.ch.
