Figure 1: Laser inscription on the girdle of a cut ruby weighing 5.475 ct (e.g. with a gem lab report number). Photo: L. Phan, SSEF.by Dr. L.E. Cartier, first published in Facette 26 (May 2020)Inscription of diamonds and gemstones has been offered for...
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 inherent traceability challenges....
first published in Facette 22 (February 2016)Figure 1: Sapphire from Andranondambo (Madagascar). Photo: SSEFIn 2016, the SSEF received a sapphire of exceptional quality and size for testing (Figure 1). The sapphire of 33 ct was characterised by a saturated blue colour, - poetically also known...
Figure 1: Part of the studied danburites for this research project. Photo: M. S. Krzemnicki, SSEFThe 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...
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...
by Dr. Michael S. Krzemnicki, first published in Facette 22 (February 2016)Figure 1: Rubies from Mozambique, from left to right: untreated, heated, heated, and fissure filled with lead glass. Photo: M. S. Krzemnicki, SSEFHeating of rubies from Mozambique at rather low temperatures is nothing...
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...
Figure 1: Iconic ruby necklace with ruby ear-pendants by Harry Winston. Photo: V. Lanzafame, SSEFby 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...
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....
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....