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Occasionally, we encounter synthetic stones at SSEF that are submitted to us by our clients. Usually they are quite surprised by our result, as the issue of synthetic stones – at least in the coloured stone market – has very much vanished in peoples’ minds,...

first published in Facette 22 (February 2016)Figure 1: Water-worn pebble and cut stone, both polycristalline kyanite.The Swiss Gemmological Institute SSEF received two blue translucent samples, a water-worn pebble, and a faceted stone of 1.72 ct cut from the same piece (Figure 1). ...

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...