Rare Earth Elements in Danburites
The calcium-boron-silicate danburite is a rather rare c […]
Vanadium-rich Ruby from Mogok, Myanmar
Mogok-type rubies are known to contain small but distinct amounts of vanadium (often in the range of 0.015 – 0.025 wt% V2O3), but are commonly highly dominated by chromium (approximately by a factor of 20-100 x) responsible for their often attractive and saturated red colour and strong fluorescence. In some c
Age Dating on Ruby set in Iconic Ruby Necklace by Harry Winston
by Dr. M. S. Krzemnicki & Dr. H.A.O. Wang, first pu […]
Chipping of Emeralds
The cleaning process of emeralds, often supported by mechanical tumbling and ultrasonic cleaning may result in chipping or even cracking of pre-existing fissures within emeralds at any time afterwards.
Why is a Diamond of Type IIb blue to greyish blue?
Comparing the absorption spectra of type IIa and type IIb diamonds greatly helps to better understand why a diamond of type IIb is blue to greyish blue.
Beware: Laser Damage in Sapphires due to Jewellery Repair
Having personally tested gemstones for more than 20 years now, the author of this short note was quite shocked in recent months to see distinct laser damage features on quite a number of sapphires which were submitted to us by different clients.
The Resurrection of Synthetic Coloured Stones
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, and is often not anymore considered a real threa
Colourless Chrysoberyl from Mogok
first published in Facette 22 (February 2016) Chrysober […]
