The Gemmological Association of Great Britain (Gem-A) recently published Issue No. 2, Volume 39, of The Journal of Gemmology, the second of 2024. With more than 100 pages dedicated to gemological news, this issue of the Journal features three extended studies among its main contents.
In the article by Shang I (Edward) Liu, Ka Yi (Angela) Man, Montira Seneewong-Na-Ayutthaya, Chanenkant Jakkawanvibul and Ann Tak-Yan Lee “Geographic Origin Determination of High-quality Green Jadeite-Omphacite Jade (Fei Cui) from Myanmar, Guatemala and Italy Using Statistical Processing Coupled with Spectroscopic and Chemical Analyses” the geographic origin of high quality green jade from Myanmar, Guatemala and Italy is distinguished. The research proposes a practical approach to determine the geographic origin of this material using characteristic spectral peaks and chemical data in combination with statistical analysis, achieving a set of key indicators useful for the identification of these three localities.
In the article “Gamma Spectroscopy—A Possible Identification Method for the Artificial Irradiation of Morganite”, authors Tom Stephan, Xiasong Li, Thomas Lind, and Vladimir Hutanu analyzed samples of morganite using gamma spectroscopy after the samples were irradiated with electrons, a treatment used to enhance the pink-orange color of the gemstone. Gamma spectroscopy detected small amounts of radioactive Caesium isotopes (132Cs and 134Cs), formed due to the natural Caesium content in morganite. Although the content is low, the study confirmed its detectability: Caesium-132 up to two months after irradiation and Caesium-134 up to 4-18 years.
In another article “The Sinoniki Spessartine Deposit in Longido, Tanzania—A New Source of Bright Orange Spessartine (‘Mandarin’) Garnet”, Tom Stephan, Thomas Lind, Claudio C. Milisenda, and Fabian Kneipp introduce the new spessartine deposit discovered in the Longido region of northeastern Tanzania. This deposit produces small, inclusion-free but highly brilliant stones known as “Mandarin garnet”.
Italy makes a return in this issue with an in-depth article by Franck Rossetto and Thierry Cathelineau on xonotlite, a calcium silicate hydroxide well-known among collectors, collected at the Posina Lakes in Veneto.
Among other articles featured in this issue is “Properties and Colouration of Orange Hackmanite from Afghanistan” by Féodor Blumentritt, Franck Notari, and Candice Caplan, dedicated to orange hackmanite from Afghanistan.
