Recently, the authors examined a 17.20 et greenish blue oval cabochon that exhibited a noticeably blurry, uneven colour distribution (Figure 18). lt had a spot RI of 1.57, as measured with a standard gemmological refractometer, and a hydrostatic SG of 2.60. Ultraviolet-visible-near infrared spectra obtained with a GL Gern Spectrometer were consistent with that of natural beryl, specifically aquamarine. lts identity as beryl was further confirmed by Raman spectroscopy (using a Magilabs GemmoRaman spectrometer with a 532 nm laser), but the reason for the unusual blurry colour distribution required further testing.
This article was first published in The Journal of Gemmology, 38(8), 2023, pp. 756-757. A pdf-file of this article is available here.
Authors
Christine Lucia Matter, FGG & Qi Wang, FGG, EG, both DGemG
© 2023 by Gem-A