Fake it ‘til you break it: Oddities and fraud cases submitted to SSEF
By Dr. Michael S. Krzemnicki, first published in Facette 30 (March 2026)
Apart from beautiful and exceptional gemstones, the SSEF also gets from time-to-time submissions which clearly fall far from that prestigious range. Oddities, imitations and evident fraud cases,
where somebody has been cheated or presumably tries to cheat unaware buyers. The following is a short tour-d’horizon through such cases which we encountered in the past few months at SSEF. Most of these cases are detected by simple gemmological testing.
Purple glass sold in Zanzibar jewellery shop as tanzanite
The first example is an unfortunate holiday souvenir. Bought as AAA- quality tanzanite with a ‘certificate of authenticity’ in a jewellery shop in Zanzibar (Tanzania), the owner submitted the stone to us for a second check. Unfortunately, we had to tell our client that the purple stone of 6.12 ct was made of glass, exhibiting under the microscope classic swirly features and no pleochroism when checked with the dichroscope.
Interestingly for us, the purple colour of the glass is related to rare earth elements (REE), namely neodymium and erbium, both elements known to cause purple to pinkish colours in industrial aluminosilicate glass. Due to the presence of these REEs in this glass, the refractive index (1.67, singly refractive!) and the specific gravity (SG: 3.45) were both distinctly higher than commonly observed in aluminosilicate glasses. However, both values are close to the RI- and SG-values of tanzanite, perhaps intended by the producer of this glass to hide the true identity of this imitation.
Blue glass sold as tourmaline with a fake ‘ID card’
Dyed quartzite bangle labelled as ‘high-quality natural jadeite’
Another classic case: Green dyed quartzite imitating jadeite is a common tourist trap on jade markets in Asia. In this case, however, the bangle was sent by an Asian client together with a document, in which he claimed to be a gemmologist and owner of a ‘gemmological laboratory’ and in which he described in detail the acoustic resonance analyses carried out on this item as his proof that it is indeed high-quality jadeite-jade (type A).
The reality is that basic testing of this bangle with the refractometer or a quick check with the microscope would have ruled out jadeite immediately even for a fresh gemmological student. Our testing with advanced methods clearly revealed that the bangle is made of quartzite, a rock consisting of small colourless quartz grains (see Raman spectra above). In addition, this quartzite bangle was heavily impregnated with a green dye with the aim to fraudulently imitate jadeite of high quality.
In summary, this dyed quartzite bangle indeed resonated well within our team of acoustic experts at SSEF, but obviously not in sync with the claims of the client and the provided documentation.
Octahedral disillusionment
