Irradiation Treatment in Rubies and other Corundum Varieties: Update about Ongoing Research at SSEF on this Issue
Irradiation of corundum varieties to change and enhance their colour is known since many decades but remains a difficult and challenging issue until today, as no gemmological method is currently known which would allow an unambiguous detection of this type of treatment.
As is known in the gem trade, the colour of certain gems may be caused or influenced by the presence of colour centres (a type of defect in the crystal structure that can absorb light and thus result in colour, that can be present both in stable or unstable form).
The spinels were nearly free of any inclusions except for a few tiny colourless forsterite inclusions. In combination with trace element analyses, the origin of these spinels could be unambiguously attributed to the famous spinel mines near Kuh-i-Lal, located in the Pamir mountains in southern Tajikistan, close
Imagine life as an emerald. Just born in the rocks and growing, you get joggled and bruised by mother nature and later by the mining process. So, already in your young age you carry quite some scars and fractures, which reduce your true beauty considerably and may not make it so easy to find a good mate (emeral
The body colour of pearls is normally related to the presence of natural colour pigments produced by the mollusc during pearl formation. Another option is to colour pearls artificially, with dyeing being the most readily available method. Often applied to rather low-quality freshwater cultured pearls, these tre
Rubies from Mong Hsu, located about 250 km southeast of the Mogok Stone Tract, entered the gem trade in the early 1990s. Since this time the Mong Hsu mines remain an important source for Burmese rubies, specifically for stones of smaller sizes (2 ct and below).
Zircon inclusions in unheated pink sapphires from Ilaka […]
Presentation at the online 2021 International Gemmological Conference by Dr. Michael S. Krzemnicki.
Raman spectroscopic investigation of zircon in gem-quality sapphire: Application in origin determination
Raman spectroscopic investigation of zircon in gem-qual […]