Low-Temperature Heated Rubies From Mozambique
by Dr. Michael S. Krzemnicki, first published in Facette 22 (February 2016) Heating of rubies from Mozambique at rather low temperatures is nothing new. Immediately after the discovery of this new deposit close to Montepuez in 2009, it was obvious that part of the new material required heat treatment befor
Sub-surface laser inscription and marking of gemstones
by Dr. L.E. Cartier, first published in Facette 26 (May 2020) Inscription of diamonds and gemstones has been offered for several years, whereby a logo or a report number is inscribed on the girdle of a stone after cutting and polishing. This is done by some natural diamond sellers or grading laboratories and s
Traceability and Blockchain for Gemstones – an Overview
Recent developments have brought‚ due diligence, along with tracking and traceability, to the forefront of discussions and requirements in the diamond, coloured stone and pearl industries. To address this trend, certification mechanisms and technologies (such as blockchain) are being developed to solve inher
DNA Fingerprinting of Pearls, Corals and Ivory: Research Update
SSEF pioneered DNA fingerprinting of pearls in 2013, in collaboration with scientists from ETH Zürich. This was the first published report of oyster DNA extraction from a pearl, allowing us to trace and fingerprint pearls of unknown origin and match them to the specific oyster species in which they formed.
Rare Earth Elements in Danburites
The calcium-boron-silicate danburite is a rather rare collector’s stone, mainly known in colourless to slightly yellowish to brownish colours from a limited number of deposits worldwide. Since 2013, new and attractive vivid yellow danburite has entered the gem trade. This new material originates from the Many
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 published in Facette 25 (February 2019) Harry Winston was certainly one of the most important and influential jewellers of the 20th century. The son of a small jewellery shop owner, Mr. Winston was fascinated by gems and jewels already at a young ag
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.