Preliminary study of defocused PL measurements of diamo […]
The SSEF is known worldwide as a leading authority in gem testing, and as such we have the great pleasure to scientifically analyse some of the most prestigious and important jewellery before it is offered up for auction or in private sales. Apart from testing the gem materials in such jewellery, we are often i
Presentation at the 2022 Rendez-Vous Gemmologiques de Paris Conference by Jean-Pierre Chalain (original version of this presentation was in French, this version has been translated into English)
As in the past, the SSEF is regularly asked by the Swiss police authorities to act as a gemmological adviser in criminal cases. Usually, these are fraud cases, involving undeclared or mislabeled gemstones or their imitations. In a recent case with about 20 stones submitted by the police, we not only found diamo
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
Treated greenish yellow diamond with brown radiation st […]
Comparing the absorption spectra of type IIa and type IIb diamonds greatly helps to better understand why a diamond of type IIb is blue to greyish blue.