Effects of gamma irradiation on ruby and pink sapphire: an update
Gamma irradiation is a treatment method that may enhance the colour and visual appearance of gemstones, such as diamond, topaz, quartz, and corundum, to name a few. This treatment method uses strong gamma rays, either from radioactive isotopes like cobalt-60 (60Co) or from a linear accelerator (LINAC), to induc
Sapphires of ‘teal’ colour from Pein-Pyit, East Mogok
The Mogok area in northern Myanmar has been known as a major source of rubies and other gems since historic times. Often referred to as the ‘Mogok Stone Tract’, this gem-rich area is located within the central part of the Mogok Metamorphic Belt which forms part of a larger metamorphic belt structure, extend
Detection of Low-Temperature Heat Treatment in Corundum: Possibilities and Challenges (2024)
Presentation by Dr. Michael S. Krzemnicki at the GILC conference in Tucson in 2024.
Dehydration of Diaspore and Goethite during Low-Temperature Heating as Criterion to Separate Unheated from Heated Rubies and Sapphires
Dehydration of Diaspore and Goethite during Low-Tempera […]
Effects of Gamma Irradiation on Ruby and Pink Sapphire and Potential Detection Methods in Gem Labs
Keywords: Ruby, Pink sapphire, Gamma irradiation, UV-VIS, Raman, R-Line
New and additional criteria to detect low-t heated corundum
Heat treatment of ruby, sapphire and other colour varieties of corundum is one of the main issues for the gem trade. As such, detecting such treatment is a major task of gemmological laboratories issuing gemstone reports. Unfortunately, and especially lately, the detection of such heating is not always straight
Ti-diffusion treated sapphire cabochons
Titanium diffusion treatment is known since decades: it can lead to a surface-related blue colour in corundum. Basically, this treatment is a heating process requiring high temperatures in combination with titanium (oxide) as an additive. During the treatment, titanium atoms penetrate into a superficial layer o
Pink sapphire with orange iron hydroxides in fissures
Padparadscha is one of the most attractive corundum varieties in the trade and is sought after for its subtle pinkish orange to orangey pink colour. Padparadscha, originally known from Sri Lanka only, is found today also in other deposits such as for example in Madagascar and Tanzania, both part of East Africa
Phase transformations as important markers for heat treatment detection of corundum and other gemstones (2023)
Presentation by Michael S. Krzemnicki, Pierre Lefèvre, Wei Zhou at the International Gemmological Conference IGC 2023 in Tokyo, Japan.
Zircon inclusion analysis for sapphire origin determination
Zircon ZrSiO₄ a very intriguing mineral, not only because it can be used as an attractive gemstone (Figure 1) but also due to the fact that it can contain minute traces of radioactive elements (U, Th), which decay over time to lead (Pb) isotopes.