Past conferences
Abstracts Library
Geographic Origin Determination of Fei Cui: A comparison of high-quality green Fei Cui from Myanmar, Guatemala, and Italy
Fei Cui is a kind of jade that is defined as a granular to fibrous polycrystalline aggregate composed solely, or principally of any of the following or any combination of the follo
Purple to bluish grey chalcedony from Ethiopia
In the past 15 years, Ethiopia has repeatedly gained attention for a variety of new gem finds. In 2008, a large deposit of white play-of-colour opal was found (Rondeau et al., 2010
Past, Present and the Future of IGC
Exactly, seventy-one years ago, in the month of October, to be precise from the 23rd to the 25th of October 1952 in Lugano, Switzerland, the inaugural meeting of the International
Color enhancement in yellow sapphire
Natural yellow sapphire is colored by one or the combination of two different chromophores, Fe3+ and the trapped hole-Fe3+ (h• -Fe3+) colour center. Fe3+ chromophore is typically
Analysis of Myanmar golden-lipped cultured pearls using X-ray radiography, EDXRF, UV-Vis-NIR and Raman spectroscopy
Myanmar golden-lipped pearl oysters (Pinctada maxima) are well-known to be found at the Myeik Archipelago – formerly also known as Mergui Archipelago – in the Andaman Sea in so
Colour varieties of gems – where to set the boundary?
In theory it is simple: a gemstone is a mineral formed in nature by geological processes and, as such, it has a mineralogical name that is scientifically defined and accepted by th
Origin Identification Characteristics of High-quality Green Jadeite
Currently occurrences of jadeite mainly include Myanmar, Guatemala, Russia, Kazakhstan and Japan. Origin has a great impact on the price of high-quality green jadeite and at presen
Sulfur-based species induced photochromism in sodalite
Sodalite Na4 (Al3 Si3 O12)Cl is a natural aluminosilicate mineral that contains sulfur or sulfur-related defects, known as chromophores (Reinen et al. 1999; Fleet et al. 2010). Hac
Fingerprint differences between Emeralds from two main zones of production in Colombia in response to input from their host rock
Although there is information about techniques to separate Colombian emerald material from that of other countries, not much information is available on how to differentiate Colomb
Quantitative estimation of spinel’s thermal and geothermal history by photoluminescence spectroscopy and its application in spinel origin determination
The thermal history of spinel can not only be used to distinguish the natural spinel from heated and synthetic ones, but also to reveal that the spinel underwent different geologic
Additional Observations on Unstable Color in Padparadscha Sapphires
For the past few years laboratories have been testing the color stability of padparadscha sapphires. It became an issue because we realized that the orange color in some pads was u
Cobalt spinel from Bai Buoi mine, Yen Bai, Vietnam
The cobalt bearing spinel from Lukande, Tanzania, discovered in 2019, has attracted much attention and several papers were published recently (Stephan & Muller., 2022, Krzemnicki e
FTIR Fingerprinting: a case study on mineral inclusion identification by FTIR applied on rubies from marble-hosted deposits
Fourier-Transform Infrared Spectrometry (FTIR) is a well-established analytical method in the field of gemmology (Suhner, 1979; Fritsch and Stockton, 1987; Smith, 1995; Beran and R
Effects of Gamma Irradiation on Ruby and Pink Sapphire and Potential Detection Methods in Gem Labs
Gamma irradiation is a non-destructive and non-invasive treatment method used to enhance the colour and aesthetic appeal of gemstones, such as diamond, topaz, quartz, and sapphire.
Influence of Irradiation on Colour Modification and Colour Stability of Rubies: A Preliminary Study
Ruby is the chromium-bearing red colour-variety of corundum Al2 O3 . Since historic times, ruby is highly popular in the gem and jewellery market because of its highly saturated re
Mechanism and Application of High-Temperature Copper Diffusion in Surface Recoloring of Labradorites
Feldspar, with the chemical formula of [KAlSi3 O8 ]x[NaAlSi3 O8 ]y[CaAl2 Si2 O8 ]z (x + y + z = 100), is one of the most important rock-forming minerals in the earth’s crust, and
Study of a historical Alexandrite from Paris school of mines collection
Rare are the scientific studies on exceptional gemstones belonging to museum collections. This investigation is part of an ongoing project, on the study of historic gems, of the Mi
Opal stability: a step toward detection
Opal is a gem of captivating beauty that stems from its complex microscopic structure composed mainly of silica. In the most striking specimens, the light diffraction from a three-
Colour change Paraiba tourmaline from Brazil
In just a few decades Paraiba tourmalines have developed into one of the most valuable and sought-after gems in the world. Of particular interest are specimens from the legendary B
Explanation on Yellow, Green and Brown Coloration Series of Basalt Related Bangkaja Sapphires
The basalt related Bangkaja sapphires, excluding the black star ones, commonly occur in three coloration series, i.e., the yellow, the green and the brown. Two representative sampl
