Bachelor thesis on heated blue zircon from different origins
Zircon (ZrSiO4) is a common accessory mineral found in rocks, as well as an inclusion in gemstones, primarily corundum. Zircon is also known as a gemstone in its own right, either colourless or in many attractive colours, the most popular of which is blue. It is important to note that the blue colour of these zircons is the result of heat treatment, which transforms rather unattractive rough material (e.g. brownish) from certain geographical origins into stones exhibiting an attractive range of blue and greenish blue colours. Greenish blue zircon is well-known in the trade from alkali basalts in the Ratanakiri Province in north-eastern Cambodia, and is also found in the Mogok area of Burma (Myanmar), where it often exhibits a ‘reverse’ colour change from violetish blue to greenish blue (Bosshart & Balmer, 2006; see also SSEF Facette No. 20, 2013, p. 19). Most recently, it has been found in Maripa in southern Malawi.
In 2025, we began a Bachelor’s research project in collaboration with Yan F. Foraita, a student at the University of Basel. The project aimed to characterise and compare a selection of blue zircons (including some unheated, original brown material) from three different deposits. The study revealed that the trace element composition of the blue zircons from these three geographic origins can be clearly separated. We would like to congratulate Yan F. Foraita on his excellent Bachelor’s thesis. The results of this study will be published in a gemmological journal in the near future and are very useful for our laboratory.
