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 internationally recognised standards allows us to perform inter-lab comparisons or track instrument performance...
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 microscope, the submitted stone showed ‘zircon-like’ cluster inclusions (Figure 2). They...
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....
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 was rather of aquamarine- to amethyst-like colours, but shortly after it was followed by...
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 being the most readily available method. Often applied to rather low-quality freshwater cultured pearls,...
The mineral chrysoberyl BeAl₂O₄ is a highly appreciated gemstone due to its rarity, brilliance, and beauty and comes in attractive colours commonly ranging from colourless (chemically pure) to yellow, yellowish green, green, and brownish green to dark brown, mostly related to the presence of iron...
Pearl testing was long limited to determining whether a pearl is natural or cultured, and whether a pearl has been treated or not. As we have considerably invested in pearl research in recent years, we have achieved significant breakthroughs, namely DNA fingerprinting for species identification...
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...
by Dr. M.S. Krzemnicki, first published in Facette 27 (June 2021)Figure 1 (left): Dyed corundum from Burma (Myanmar), mimicking a beautiful pinkish red ruby. Photo: J. Xaysongkham, SSEF. Figure 2 (center and right): Fissures filled with red oil in this treated (dyed) corundum. Photos: M.S. Krzemnicki,...
by Dr. M.S. Krzemnicki, first published in Facette 27 (June 2021)The two Canary tourmalines (5.2 ct and 19 ct) which were recently analysed at SSEF. Composite photo: Wikimedia commons & SSEF.Tourmaline is a mineral group of complex boro-silicates and is well known to produce gemstones in...