by Dr. M.S. Krzemnicki, first published in Facette 27 (June 2021)Figure 1: Poudretteite of 1.53 ct set with diamonds in a ring. Photo: SSEF.In recent months, the SSEF received again a number of very rare collector stones for testing. These included poudretteite, musgravite, taaffeite, and grandidierite of...
by Dr. L. Speich & J.-P. Chalain, first published in Facette 27 (June 2021)Figure 1: Two exceptional asteriated diamonds received at SSEF. From left to right: octahedron showing six brownish lobes (3.72 ct); flat half-octahedron showing three lobes (3.77 ct); sideview of the second stone showing the...
Rubies from Mong Hsu, located about 250 km southeast of the Mogok Stone Tract, entered the gem trade in the early 1990s. Since this time the Mong Hsu mines remain an important source for Burmese rubies, specifically for stones of smaller sizes (2 ct and...
We recently tested a pearl jewellery set that consisted of 63 natural pearls, with 61 of them being strung on a thread and two additional loose natural pearls. To our knowledge, this is the first time that pearls from Pinctada persica have been reported....
Radiometric U-Pb dating is a promising tool in gemstone testing and is used at SSEF as an advanced analytical procedure since several years. However, this method is usually only applicable when the gemstone presents sufficient traces of radiogenic elements either in its crystal structure or...
by Dr. M.S. Krzemnicki, first published in Facette 26 (May 2020)Figure 1: Red ruby or pink sapphire: that’s the question. Photo: A. Castillon, SSEF.In theory it is simple: a gemstone is a mineral formed in nature by geological processes and, as such, it...
by Dr. M.S. Krzemnicki, first published in Facette 26 (May 2020)Figure 1. Portrait of Hortense Eugénie Cécile de Beauharnais (1783-1837) Queen of Holland and mother of Napoleon III, wearing the talisman with the front side facing out. Painting by Felix Cottreau. Courtesy of...
by Dr. M.S. Krzemnicki, first published in Facette 26 (May 2020)Figure 1: Iconic rubies from Mozambique all tested by SSEF and described below, all of exceptional size and quality. Photo assemblage: M.S. Krzemnicki, SSEF.In the past decade, rubies from Montepuez...
The Queen Mary Pearl in a setting by Cartier. Photo: L. Phan, SSEFFirst published in Facette 26 (May 2020)As a foremost authority in the testing of natural pearls, the SSEF has had the chance in the past few decades to see and analyse the most...
by Dr. M.S. Krzemnicki, first published in Facette 26 (May 2020)Figure 1: Roman sapphire intaglio engraved with the mythical creature hippocamp. Photo: V. Lanzafame, SSEF.In 2019, the Swiss Gemmological Institute SSEF in collaboration with the Istituto Gemmologico Nazionale IGN Rome (Italy) were...