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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)
The value of pearls: A historical review and current trends
The value of pearls: A historical review and current trends. Published in GemGuide, May/June 2022, 1-8.
Paraiba or Not? Cu-bearing Tourmaline with a Distinct Fe Concentration
Paraiba or Not? Cu-bearing Tourmaline with a Distinct Fe Concentration. Published in Journal of Gemmology, 2022, 38 (1), 20-22.
Natural pearl necklace with one imitation pearl
Our testing not only revealed the presence of 40 natural pearls of a quite remarkable diameter (8-11 mm), but in addition one imitation pearl consisting of a plastic bead covered by a ‘lacquer’ co
Heated spinel from Tajikistan
The spinels were nearly free of any inclusions except for a few tiny colourless forsterite inclusions. In combination with trace element analyses, the origin of these spinels could be unambiguously at
The science of gem testing at SSEF: a fascinating tale
Gemmology is a science with its foundations more than a hundred years ago, specifically driven by the emergence of synthetic stones and cultured pearls in the gem trade in the early 20th century.
Visit to the Mong Hsu ruby deposit in Myanmar (Burma)
Mong Hsu is one of the reputed ruby deposits in Myanmar (Burma). It is located about 250km southeast of Mogok, in the Shan State, in northeastern Myanmar.
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 gemst
Pair of sautoirs by René Lalique
René Lalique (1860-1945) was one of the most ingenious and creative designers of jewellery and glass objects at the end of the 19th and beginning of the 20th century. He significantly contributed to
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 di
Cultured pearls in a bracelet of historic design
An antique-style bracelet with diamonds and pearls was recently submitted to SSEF for testing (Figure 1). Despite the complex setting, we were able to analyse all the pearls and found, that five of th
A never-ending story: recheck service and report validity check on myssef.ch for emeralds
Imagine life as an emerald. Just born in the rocks and growing, you get joggled and bruised by mother nature and later by the mining process. So, already in your young age you carry quite some scars a
Zircon inclusion analysis for sapphire origin determination
Zircon ZrSiO₄ a very intriguing mineral, not only because it can be used as an attractive gemstone (Figure 1) but also due to the fact that it can contain minute traces of radioactive elements (U,
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 intern
Beware of synthetic ruby with ‘zircon-like’ cluster inclusions
Very recently, we tested a tricky case of a synthetic ruby (Figure 1) of 4.27 ct, submitted to SSEF as a natural stone accompanied by two lab reports confirming its natural origin. Under the microscop
Souvenirs from the past: doublets uncovered at SSEF
From time to time, we get a flashback in gemmological history. This is specifically the case when we receive an antique ring with an ‘early’ Verneuil synthetic ruby showing strongly curved growth
New copper-bearing tourmalines from Nigeria
Copper-bearing tourmaline from Nigeria is known in the trade since about two decades (Milisenda 2001, Henricus, 2001; Smith et al., 2001; Zang et al., 2001). The first reported material from Nigeria w
Natural pearls dyed green
The body colour of pearls is normally related to the presence of natural colour pigments produced by the mollusc during pearl formation. Another option is to colour pearls artificially, with dyeing be