Rare Earth Elements in Danburites
The calcium-boron-silicate danburite is a rather rare c […]
Polycristalline Kyanite
first published in Facette 22 (February 2016) The Swiss […]
Colourless Chrysoberyl from Mogok
first published in Facette 22 (February 2016) Chrysober […]
Study of opalised Dinosaur Vertebra
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 Elizabeth
Colourless Diopside from Kenya and Canada
first published in Facette 22 (February 2016) Diopside, […]
Zircon Showing Asterism
first published in Facette 22 (February 2016) Martin St […]
Colour-Changing Zircon
by Dr. M.S. Krzemnicki, first published in Facette 20 ( […]
The Usambara Effect and other colour-change Effects in Gemstones
Colour change in gemstones is an interesting phenomenon, which can be due to a number of reasons. One of the causes is the so called Usambara effect, a type of colour change which is not so well known in the public. In contrast to the alexandrite effect, this phenomenon is not dependent on the type of illuminat
The Beryl Group – an Overview
The Beryl Group – an Overview. Published in Journal of […]