Micro-World Gems & Gemology, Winter 2020, Vol. 56, No. 4

Zircon in Jadeite Jade

Raman identified this crystal as “high” zircon.
This doubly terminated tetragonal crystal in jadeite jade was identified as “high” zircon using Raman spectroscopy. Photomicrograph by Tyler Smith; field of view 2.90 mm.

One translucent green bangle bracelet recently examined by the author contained an interesting inclusion. The material was identified as dyed and polymer-impregnated jadeite jade using standard gemological testing and advanced spectroscopy, including UV-Vis, Raman, and infrared. This material would be classified as C-type jade in the trade.

Microscopic examination revealed a surprisingly well-formed transparent brownish crystal inclusion (see above). Raman analysis of the doubly terminated tetragonal prism revealed it to be “high” zircon (ZrSiO4). To confirm this, the full width at half maximum (FWHM) of the internal stretching mode at 1008 cm–1 was calculated as 6.05 cm–1, indicating a high level of crystallinity, as this band is known to broaden as metamictization occurs (L. Nasdala et al., “Metamictization and U-PB isotopic discordance in single zircons: A combined Raman microprobe and SHRIMP ion probe study,” Mineralogy and Petrology, Vol. 62, 1998, pp. 1–27).

Although interstitial zircon grains are not uncommon in jadeites, such a euhedral crystal is rarely observed and is especially unexpected considering the various treatments its host had undergone.

Emily Jones is a staff gemologist at GIA in New York.