Spessartine garnet from Burma and Nigeria (34 ct), arranged on the print out of the chemical analysis (EDxrF) of the Nigerian sample. the main peaks in the XRF-spectrum are due to the presence of manganese within their crystal structure. Photo: M.S. Krzemnicki, SSEF.first...
first published in Facette 22 (February 2016)Chrysoberyl is found in various colours, mostly yellow to green and brown due to iron, light green to bluish green (vanadium) or as the colour-changing variety alexandrite (due to chromium).In rare cases, chrysoberyl is also found in...
Figure 1: Vanadium-bearing “mint green” chrysoberyl from Tanzania of exceptional quality before (45 ct) and after cutting (40 ct). Photo: M.S. Krzemnicki, SSEF.first published in Facette 21 (February 2014)Vanadium-bearing chrysoberyl of light green to saturated green colour has been known in the trade since...
The ASDI machine currently in operation at SSEF.by J.-P. Chalain, first published in Facette 21 (February 2014)In 2013, numerous trade-press articles and gemmological laboratory alerts warned the diamond industry about the presence of synthetic diamonds mixed together with, or presented as, natural diamonds. These...
Vivid blue cobalt-spinel from Vietnam (left) and blue cobalt-bearing spinel (right) showing a colour change from blue in daylight to purplish-blue in incandescent light.by Dr. M.S. Krzemnicki, first published in Facette 21 (February 2014)In 2013, Ms. Carina Hanser from the University Freiburg im...
A nice selection of pipi pearl samples, together with a Pinctada maculata shell sample. Photo: SSEF.first published in Facette 21 (February 2014)In 2013, SSEF received a lot of beautiful small so-called Pipi- pearls from the Pacific. These natural pearls are generally rather...
An exceptional ruby specimen from Didy, Madagascar. Photo: SSEF.by Dr. M.S. Krzemnicki, first published in Facette 21 (February 2014)Since 2012, a new gem find near Didy (Madagscar) has produced some sapphires and rubies of outstanding size and quality (Pardieu et al. 2012, Peretti...
There is a long established tradition in the trade to fill open fissures in emeralds with colourless fillers, such as oil, wax and (artificial) resins, to reduce their visibility. Disclosure of such treatments is mandatory (CIBJO), including a quantification of the filler substance, as this...
In February 2016 Dr. Laurent Cartier had the opportunity of visiting Jewelmer pearl farms near Palawan Island in the Philippines and observing the different culturing techniques required to harvest golden South Sea pearls. ...
Recently, the Swiss Gemmological Institute SSEF received an exceptional opalised dinosaur vertebra for study. This specimen was reportedly from Lightning Ridge (New South Wales in Australia) – a world famous source of dark opals and opalised plant and animal fossils - and was already photographed by...