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
Eclogitic orange-yellow diamonds coloured by the 480 nm band
We recently acquired three orange-yellow diamonds for the SSEF collection research. These diamonds immediately retained our attention when we did the UV-vis-NIR spectra to identify the defect at the origin of their colour.
CVD synthetic diamond with colour shift
Last November, the SSEF received an interesting round brilliant colourless (with a greyish tint) diamond of ca. 0.7 ct. mounted on an earring for testing.
Fake it ‘til you break it: Oddities and fraud cases submitted to SSEF
Apart from beautiful and exceptional gemstones, the SSEF also gets from time-to-time submissions which clearly fall far from that prestigious range.
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).
Renaissance point cut diamond and gold ring
Since the beginning of human history, jewellery has been created, with its materials, including gemstones and precious metals, being reused to make new pieces.
Visit of the Letšeng diamond mine in Lesotho
In November 2025, Dr. Michael S. Krzemnicki and Dr. Michael Mintrone, Head of the Diamond Department at SSEF, were invited to visit the Letšeng diamond mine in Lesotho as part of a collaboration project. The Letšeng diamond mine is known for its large diamonds of exceptional quality and is the h
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.
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