Diamonds
Complete 4Cs –carat, clarity, colour, cut- grading of natural diamonds can be carried out by SSEF. The diamonds must be loose and cannot be graded in a mounted state. SSEF does not offer grading reports for synthetic diamonds.
We also offer grading services for coloured diamonds and authentication and quality control of small diamonds. The order forms for colourless, coloured and small diamonds can be found here.
Explore our research library
Preliminary study of defocused PL measurements of diamonds
Preliminary study of defocused PL measurements of diamonds. IGC 2021 Proceedings, 10-11.
Synthetic moissanite with reflectivity of diamond
Synthetic moissanite with reflectivity of diamond. The Journal of Gemmology, 38(4), 323-325.
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
ISO standards in the diamond trade: history and benefits
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
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) lig
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
Treated greenish yellow diamond with brown radiation stains
Treated greenish yellow diamond with brown radiation stains. The Journal of Gemmology, 680-683.
Diamonds as a window into the earth
by Dr. L. Speich, first published in Facette 26 (May 2020) Diamond is valuable as a gemstone but it is also a mantle geologist’s best friend because it provides a rare opportunity to study processes that occur deep in the Earth. Most diamonds form in the so-called lithospheric mantle within a
Why is a Diamond of Type IIb blue to greyish blue?
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.
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
Undisclosed natural diamonds mixed in a parcel of synthetic diamond
by J.-P. Chalain, first published in Facette 22 (February 2016) In 2016, our Diamond Department acquired a parcel of small colourless synthetic diamonds produced in Europe by the HPHT method. The complete study of these series of melee size synthetic diamonds (SSEF Research project 80602) is pa