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Further Characterisation of Native Copper Inclusions in Cu-Bearing Tourmaline
Further Characterisation of Native Copper Inclusions in Cu-Bearing Tourmaline. The Journal of Gemmology, 38(5), 427-429.
Frequently asked questions about SSEF courses
Frequently asked questions about SSEF courses Welcome to our faq dedicated to SSEF courses.For any question or inquiries, please contact us. Quick navigation to: About SSEF courses Location, schedule, equipment Registration & payments Accomodation & restaurants About SSEF courses Why take a course at SS
SSEF on-site testing in Hong Kong, 14 – 24 September 2023
We will be in Hong Kong 14 – 24 September offering our on-site testing services, during the upcoming Hong Kong Jewellery and Gem Fairs. Equipped with our mobile instruments and spectrometers, we will be testing coloured gemstones (no diamonds or pearls) at the Asia World Expo (AWE, 18 – 22 September 2023, b
Irradiation Treatment in Rubies and other Corundum Varieties: Update about Ongoing Research at SSEF on this Issue
Irradiation of corundum varieties to change and enhance their colour is known since many decades but remains a difficult and challenging issue until today, as no gemmological method is currently known which would allow an unambiguous detection of this type of treatment.
Led light boxes for standardized lighting of coloured stones and diamonds
In the past, coloured gemstones and diamonds were often examined in natural daylight, but reproducing such specific lighting conditions was challenging. Some impractical methods had been suggested, like grading only during specific hours or facing northward, especially during cloudy weather.
At the frontier of research: irradiation experiments on corundum
As is known in the gem trade, the colour of certain gems may be caused or influenced by the presence of colour centres (a type of defect in the crystal structure that can absorb light and thus result in colour, that can be present both in stable or unstable form).
Purple love
It is always a pleasure for our team to analyse gemstones which are not so common, or sometimes even very rare, but which may compete in beauty and quality (but often not in hardness) with the most prestigious classic gemstones.
Dark purple chrysoberyl
Since about three years, we see at SSEF occasionally chrysoberyl samples of very dark purplish to purplish brown colour, sometimes of quite impressive size (>10 ct). Based on chemical composition, these chrysoberyls show distinct concentration of chromium, but no evident change of colour, thus do not fit the cr
Jadeite: impregnated and dyed
Jadeite-jade of saturated emerald green colour is highly valued in Asia. It is therefore not astonishing to see in the market either heavily treated jadeite-jade or even imitations made of different minerals which pretend to be fine quality jadeite-jade of “Imperial green” colour.
Saturation too low for Paraiba tourmaline
Copper-bearing tourmaline, also known as Paraiba tourmaline in the trade, may come in a range of colours from blue to green. Similarly, the colour saturation of such copper-bearing tourmalines may vary largely, from saturated and vibrant – also known as “electric” or “neon” – to very light coloured.