Gemstones on gold Hellenistic (late 4th century B.C., 1st A.D.) jewels, exhibited at the Benaki Museum of Athens, were analyzed "in situ" by means of two non-destructive and portable analytical techniques. The composition of major and minor elements has been determined by using the new portable PIXE-alpha spectrometer. This spectrometer, according to its analytical features, allows the determination of matrix elements from Na up to Zn through the K-lines and the determination of higher atomic number elements via the L or M-lines. The analyzed red stones resulted to be red garnets, displaying a compositional range from Mg-rich garnet to Fe-rich garnet. The complementary use of a portable XRF spectrometer has provided additional information on some trace elements (Cr and Y), which are considered to be important for the chemical separation between different garnet groups. A comparison of our results with recent literature data offers useful indications about the possible geographical provenance of the stones. The analytical techniques, their complementarity and the results obtained are presented and discussed.
Non-destructive and "in-situ" characterization of gemstones on museum jewels. The complementary use of PIXE-alpha and XRF portable systems
F P Romano;
2004
Abstract
Gemstones on gold Hellenistic (late 4th century B.C., 1st A.D.) jewels, exhibited at the Benaki Museum of Athens, were analyzed "in situ" by means of two non-destructive and portable analytical techniques. The composition of major and minor elements has been determined by using the new portable PIXE-alpha spectrometer. This spectrometer, according to its analytical features, allows the determination of matrix elements from Na up to Zn through the K-lines and the determination of higher atomic number elements via the L or M-lines. The analyzed red stones resulted to be red garnets, displaying a compositional range from Mg-rich garnet to Fe-rich garnet. The complementary use of a portable XRF spectrometer has provided additional information on some trace elements (Cr and Y), which are considered to be important for the chemical separation between different garnet groups. A comparison of our results with recent literature data offers useful indications about the possible geographical provenance of the stones. The analytical techniques, their complementarity and the results obtained are presented and discussed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
