Raman spectroscopic investigation of zircon in gem-quality sapphire: Application in origin determination
Raman spectroscopic investigation of zircon in gem-quality sapphire: Application in origin determination. Published in Journal of Raman Spectroscopy, 2021, 1–11. Link to article
Beware: Laser Damage in Sapphires due to Jewellery Repair
Having personally tested gemstones for more than 20 years now, the author of this short note was quite shocked in recent months to see distinct laser damage features on quite a number of sapphires which were submitted to us by different clients.
Historic Sapphire of Catherine the Great
SSEF had the pleasure to add to this eclectic (data) collection the famous sapphire of Catherine the Great, a historic gem from Ceylon (Sri Lanka) of exceptional quality and beauty.
Ethiopia: New Source for Sapphires and Emeralds
In 2016 the first emeralds appeared in the gem trade which reportedly came from new deposits discovered near the town of Shakiso in southern Ethiopia. Soon after, some of these stones partly of high quality were submitted to the SSEF and we were able to collect microscopic and analytical data and to integrate a
Padparadscha-like fancy sapphires with unstable colours
Fancy sapphires found in recent years in Madagascar brought to light colour stability issues. Some of these samples show an unstable colour, shifting from pinkish orange (padparadscha-like) to pink after a fading test are reported. We report on research findings on these stones and explain the causes and implic
GemTOF Analyses of Sapphires from Madagascar and Kashmir
In the beginning of 2017, gem testing laboratories started to receive cut stones from a new area for gem analysis and issuing reports. As stated in a trade-alert by SSEF in early 2017, some of this new sapphire material may resemble internal features of Kashmir blue sapphires, therefore careful microscopic inve
The Talisman of Charlemagne: New Historical and Gemological Discoveries
The Talisman of Charlemagne: New Historical and Gemological Discoveries. Published in Gems & Gemology, 2019, 55(1), 30-46.
Gemmological Analysis of a Roman Sapphire Intaglio and Its Possible Origin
Gemmological Analysis of a Roman Sapphire Intaglio and Its Possible Origin. Published in Journal of Gemmology, 2019, 36(8), 710-724.
Sapphires Heated with Pressure – A Research Update
Sapphires Heated with Pressure – A Research Update. Published in InColor, Spring 2019, 86-90.
Padparadscha-like Fancy sapphires with Unstable Colours Colouration Mechanisms and Disclosure
Padparadscha-like Fancy sapphires with Unstable Colours: Colouration Mechanisms and Disclosure. Published in InColor, 2019, No. 41, 92-94.