Gemmological study of the medieval Königsfelder diptychon
In 1298 AD, the king of Hungary Andreas II presented to his wife Queen Agnes a stone-set wooden altar piece as a royal wedding present. This small medieval artwork, known today as the Königsfelder diptychon, was originally made in Venice.
Gemtof successfully passed G-Chron 2019 proficiency test on zircon U-Pb dating
The quality and consistency of analytical data is important for gem labs in order to provide replicable results to gemmologists over a long period of time. In addition, the accuracy compared to internationally recognised standards allows us to perform inter-lab comparisons or track instrument performance and tr
A new led daylight source for diamond colour grading
In 2020, a novel light source for the colour grading of diamonds was developed in a collaboration between SSEF and the Department of Physics, University of Basel (see Figure 1). In contrast to many of the models on the market, the new light source uses state-of-the-art LED (Light Emitting Diode) lights instead
Zircon inclusions in unheated pink sapphires from Ilakaka, Madagascar: A Raman spectroscopic study
Zircon inclusions in unheated pink sapphires from Ilakaka, Madagascar: A Raman spectroscopic study. Published in IGC 2021 Online Proceedings, 21-23. https://www.igc-gemmology.org/igc-2021-online
New statistical methods for analysis of gemstones
Based on real case studies on sapphire and emerald specimens, we here present how a simultaneous multi-element approach assists origin determination. Instead of pre-defining a list of isotopes in advance, routine analysis of blue sapphires using LA-ICP-TOF-MS detects rarely occurring trace elements such as bery
SSEF introduces machine learning algorithm for data visualization
by Dr. H.A.O. Wang, first published in Facette 21 (June 2021) In January 2021, the Swiss Gemmological Institute SSEF published a scientific article in the Journal of Analytical Atomic Spectrometry (Figure 1) about multi-element analysis of gemstones and machine-learning-assisted data visualization, with a part
Sub-surface laser inscription and marking of gemstones
by Dr. L.E. Cartier, first published in Facette 26 (May 2020) Inscription of diamonds and gemstones has been offered for several years, whereby a logo or a report number is inscribed on the girdle of a stone after cutting and polishing. This is done by some natural diamond sellers or grading laboratories and s
ASDI (Automated Spectral Diamond Inspection)
by J.-P. Chalain, first published in Facette 21 (February 2014) In 2013, numerous trade-press articles and gemmological laboratory alerts warned the diamond industry about the presence of synthetic diamonds mixed together with, or presented as, natural diamonds. These announcements pointed out that not onl
X-Ray Computed Microtomography at SSEF
by Dr. F. Herzog & M.S. Krzemnicki, first published in Facette 20 (January 2013) For the last few years SSEF has seen increased demand for analysis of pearls. This is not astonishing. On the one hand, the supply of natural pearls that grow or were grown without any human intervention is limited. On the oth
The Detection of HPHT-treatment of Diamonds at SSEF: 20 Years later
In 2000, SSEF announced that it was able to identify the HPHT treatment of type II diamonds. About 20 years later, this article summarizes how we were able to achieve this breakthrough and which people from the trade and other research institutions were involved in this important step.