Spectrofluorometer: New instrument at SSEF
We have acquired a new instrument at SSEF: a JASCO FP-8550 spectrofluorometer. A spectrofluorometer is a device that can measure fluorescence excitation and emission spectra.
Phosphorescence spectrometry of diamonds
The JASCO FP-8550 spectrofluorometer. The instrument has a variety of applications. Here, we report on the phosphorescence lifetime study of a 0.705 ct, round, brilliant-cut, colourless (H/VS1), natural diamond (reference NBMJ).
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 This small medieval artwork, known today as the Königsfelder diptychon, was originally made in Venice.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