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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...

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...

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....