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 bands, or, as in the past few months, when clients submit us doublets.
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) lights instead
A gemmologist’s delight: poudretteite, musgravite, taaffeite, and grandidierite
by Dr. M.S. Krzemnicki, first published in Facette […]
Zircon inclusions in unheated pink sapphires from Ilakaka, Madagascar: A Raman spectroscopic study
Zircon inclusions in unheated pink sapphires from Ilaka […]
Colour varieties of gems – where to set the boundary?
by Dr. M.S. Krzemnicki, first published in Facette 26 ( […]
New statistical methods for analysis of gemstones
Based on real case studies on sapphire and emerald specimens, we here present how a simultaneous multi-element approach assists origin determination. Instead of pre-defining a list of isotopes in advance, routine analysis of blue sapphires using LA-ICP-TOF-MS detects rarely occurring trace elements such as bery
Deep purple vesuviatine from Pakistan
by Prof. H.A. Hänni, first published in Facette 26 (May […]
Green spodumene sold as emerald imitation
Spodumene crystals (longest item about 50 cm long and 5.9 kg heavy) submitted to SSEF as new 'emeralds' from Pakistan shown here together with a faceted emerald from Pakistan
Age dating as a testing procedure for gemstones and biogenic gems
by Dr. M.S. Krzemnicki, first published in Facette 26 ( […]
Raman spectroscopic investigation of zircon in gem-quality sapphire: Application in origin determination
Raman spectroscopic investigation of zircon in gem-qual […]