UMaine TODAY Insights - November/December 2008
The case of the stolen emeralds
In July, U.S. Immigration and Customs Enforcement (ICE) announced the return to the Colombian government of more than 60 Precolumbian artifacts that were seized in Florida in 2005. The recovered artifacts that had been smuggled into the United States included more than a dozen emerald pieces that were studied by University of Maine physicists March 18 after they were brought to campus by ICE officers to determine the gems' trace elements.
Earlier this year, Professor of Physics C.T. Hess was contacted by the State Department after a federal official found reference to a research paper published in 1998 in the journal Archaeology. In the paper, Hess and two coauthors - then Hudson Museum director Stephen Whittington and gemologist James Vose of Lincoln - detailed the use of X-ray fluorescence spectroscopy to determine the trace elements in another Precolumbian artifact known as "the emerald man," a carved figurine that is part of the Palmer Collection in the Hudson Museum.
After a day of testing in his lab this spring, Hess and his students - Joshua Wright, Douglas Cahl and Anna Schliep - determined that the trace elements in the confiscated emeralds revealed that they were mined from one source. X-ray fluorescence spectroscopy helps researchers determine the chemical components in samples, providing clues to geological origins.
The research results on the now repatriated emeralds - 14 stones with drilled holes for what was probably a necklace, and a tiny carved frog figurine - were reported in a senior thesis in April by Joshua Wright.
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