Rarities and Collector Stones Tested at SSEF
The daily routine at SSEF usually consists of testing rubies, sapphires, emeralds, pearls and diamonds. Although sometimes challenging and interesting, especially taking into account the quality and the documented historical provenance of some of these gems and jewellery items, it is also always of great intere
Purple Mozambique Garnet
In early 2016, attractive bright purple garnets arrived at SSEF in Bangkok, Basel and Hong Kong. Based on client information, they are from a new mine, Padagaga in the Chimoio area in Mozambique, which was discovered recently.
Grandidierite and other Rare Gemstones at SSEF
We would like to present three minerals which were tested in the past few months at SSEF and which at least partially made headlines in the news for collectors and aficionados of such gemmological rarities.
U–Pb Dating of Zircon and Zirconolite Inclusions in Marble-Hosted Gem-Quality Ruby and Spinel from Mogok, Myanmar
U–Pb Dating of Zircon and Zirconolite Inclusions in Marble-Hosted Gem-Quality Ruby and Spinel from Mogok, Myanmar. Published in Minerals, 2020, 10, 195. Link to article
Exceptional Spessartine Garnets
first published in Facette 21 (February 2014) In 2013, the SSEF tested a number of very outstanding spessartine garnets. This manganese dominated member of the garnet group commonly shows a highly attractive and vivid orange colour and is thus also known and described in the trade as ‘Mandarin garnet
Exceptional Colour Change Garnets Showing the Usambara Effect
by Dr. M.S. Krzemnicki, first published in Facette 21 (February 2014) Colour change, also known as“alexandrite effect” has been studied extensively since it was first described in 1831 for alexandrite (chromium-bearing variety of chrysoberyl) from Russia (von Pott, 1842). Since then, numerous minerals or g
Colour varieties of gems: where to set the boundary
Colour varieties of gems: where to set the boundary? Published in InColor, 2020 Winter, 45, 92-95.
Where is the boundary between colour varieties of gems? (2019)
Red Ruby or Pink Sapphire, that’s the Question. Where is the boundary between colour varieties of gems? Presentation by Dr. Michael S. Krzemnicki, SSEF at European Gemmological Symposium (EGS) 2019 in Idar-Oberstein.
Grossular from Tanzania with Uncommon Inclusions
Grossular from Tanzania with Uncommon Inclusions. Published in Journal of Gemmology, 36(6), 500-501.
Gemmological Analysis of a Roman Sapphire Intaglio and Its Possible Origin
Gemmological Analysis of a Roman Sapphire Intaglio and Its Possible Origin. Published in Journal of Gemmology, 2019, 36(8), 710-724.