Corundo-Beryl

In gemological practice, there are very fascinating cases with the diagnosis of jewelry inserts. Thus, when identifying an insert made of opaque beryl (with refractive indices of 1.578-1.587, which fully corresponds to the declared mineral appearance), Raman spectrometry (with an exciting source at a wavelength of 532 nm) with multiple measurements from different positional positions of the sample under study gave spectra characteristic of corundum (with peaks at 4363 and 4393 cm-1). Such a discrepancy between the results of the two diagnostic methods does not contribute in any way to the determination of the mineral. Therefore, after additional (more thorough) cleaning, the sample was re-visually examined under additional lighting and at a higher magnification (up to 120X). Amphibole, micaceous minerals and hematite were found among the inclusions, but there were no inclusions resembling corundum in any way.

However, a feature was revealed – high microcracking and impregnation of the insert in order to fix the raw materials during cutting.

After repeated diagnosis, the result remained unchanged. However, after the corundum lines were removed from the measurement range and the Raman spectrum was removed again, the result turned out to be quite consistent with beryl (196, 262, 400, 700, 1020, 1067, 3611 see-1).

Probably, corundum or corundum-containing abrasive was used when cutting the stone, and the presence of micro cavities filled with an adhesive composition contributed to the retention of corundum particles, which, due to its stronger luminescence, completely drowned out the spectral luminescent lines of beryl.