Transparent Spinel Inclusion in Pink Sapphire
The S Gemmological Institute Gem Lab recently examined 155 sapphires of assorted color, sourced from the Mogok Stone Tract in Myanmar. Among these, a pink sapphire weighing 1.166 ct exhibited a significant crystal inclusion extending to the table facet (see above). This transparent inclusion was identified by Raman spectroscopy as spinel. Internally, the inclusion appeared clear and smooth, while the surface-reaching face exhibited signs of scratching due to the low hardness of spinel compared to the sapphire host.
In the Mogok area, spinel inclusions in pink sapphire are not unusual, as both pink sapphire and spinel have been discovered in the marble-hosted formations. Although spinel inclusions have been previously reported in Burmese ruby (E.B. Hughes and W. Vertriest, “A canary in the ruby mine: Low-temperature heat treatment experiments on Burmese ruby,” Winter 2022 G&G, pp. 400–423), and green gahnospinel inclusions have been documented in blue sapphire from Sri Lanka (Winter 2023 G&G Micro-World, p. 503), this spinel inclusion in a pink sapphire from Mogok was unusually large and distinct.
.jpg "YMAL GIA Ed")
