Nickel-bearing type IA natural colourless diamond
In gemmology, nickel is generally associated with synthetic HPHT diamonds through the presence of the well-known nickel-related (Ni-related) centre at 883/885 nm, which is rarely present in natural diamonds.
A descriptive study on as-grown and HPHT-treated CVD synthetic diamonds
The Swiss Gemmological Institute is testing more than one million colourless melee diamonds for the Swiss watch and jewellery industry on an annual basis to guarantee that no synthetic diamonds are mixed within natural melee diamond batches.
Jean-Pierre Chalain: over 3 decades of diamonds at SSEF
On March 31st 2024, Jean-Pierre Chalain – director of SSEF’s diamond department- retired from SSEF and handed over the diamond department to Dr. Michael Mintrone and his team.
A study of nickel-bearing type Ia diamonds
A study of nickel-bearing type Ia diamonds. IGC 2023 Proceedings, 37-39.
Pearls & diamonds: a royal selection
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
Synthetic moissanite with reflectivity of diamond
Synthetic moissanite with reflectivity of diamond. The Journal of Gemmology, 38(4), 323-325.
ISO standards in the diamond trade: history and benefits (2022)
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)
Diamond fraud uncovered
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
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
Two exceptional asteriated diamonds
by Dr. L. Speich & J.-P. Chalain, first published in Facette 27 (June 2021) Recently, SSEF received two so-called asteriated diamonds for authentication. Asteriated diamonds are rare and highly prized amongst collectors for their beautiful and unique appearance. The two stones received in our lab