Study on sapphires with “exotic” elements and implications for heat treatment detection
In a recent study, we analysed a series of unheated gem-quality sapphires containing ‘exotic’ elements such as Sn, Nb, Zr, Ta, W, also known as high-field-strength elements.
Rare encounter: Sapphire with grandidierite needle inclusion
Recently, the SSEF received for testing a sapphire of pale blue colour with a distinct colourless needle-like inclusion, resembling to some extent long prismatic pargasite needles known in Kashmir sapphires.
Unheated pink sapphire from Madagascar with FTIR bands at 3232 and 3185 cm–1
FTIR spectroscopy has long been used to detect heat treatment of corundum via the presence of specific absorption bands related to structurally bonded hydroxyl groups in corundum.
Unheated Pink Sapphire from Madagascar with OH-related 3232 and 3185 cm–1 FTIR Bands
The alluvial gem deposits of Ilakaka in south-western Madagascar have been known for more than two decades as an important source of corundum, mainly producing pink to purple stones, but also blue, yellow and padparadscha varieties.
Effects of Gamma Irradiation on Corundum: Towards a Potential Detection Method
Corundum, encompassing the highly prized ruby and sapphire varieties, stands as a cornerstone of the global gemstone market.
HFSE-enriched sapphires of gem quality: A combined FTIR and trace element study and implications for heat treatment detection
Gem-quality sapphires containing ‘exotic’ elements such as Sn, Nb, Zr, Ta, W, are of special interest in gemmological research, as the concentration of these so-called high-field- strength-elements (HFSE) often correlate with detectable traces of naturally incorporated beryllium (Whatanakul et al. 2004, Par
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 […]