Past conferences
Abstracts Library
Irradiation treatment and gamma-spectroscopy of morganite
The pink variety of beryl, morganite, is one of the most popular orangey-pink to pink gemstones. Its colour is attributed to manganese, both Mn2+ and Mn3+ (Nassau & Wood, 1968, Woo
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.
An implementation of machine learning in ruby and sapphire origin determination
Country-of-origin is one of the most important value factors of corundum (ruby and sapphire) due mainly to its historical or legendary popularity in the trade. Generally, gemmologi
Low Temperature Heat Treatment of Burmese Ruby
Detection of low-temperature heat treatment (below 1200°C) in ruby and sapphire can present challenges to gemologists, as alterations to the material are often subtle. In this stu
A study of nickel-bearing type Ia diamonds
We present a detailed FTIR and PL spectroscopic study (i.e. at 298 and 77°K) of a large number of colorless (i.e. color D to G) type Ia diamonds (i.e. >200), showing the presence
Microfeatures of Beryl Group Gems including the Newest Mineral Variety, Johnkoivulaite
Beryl group minerals often provide clues to their pegmatitic origin in the suite of inclusions contained within such gems. They regularly showcase examples of pegmatitic minerals s
A study of Chikayama’s gem and mineral collections and building a gem museum
Based on the belief that “a gemstone is art and science,” Mr. Akira Chikayama devoted his life to gemological research and study for the benefit of people involved in gemstones
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
Nacreous Blister Pearl Discovered in Edible Oyster (Crassostrea gigas)
A baroque pearl with a gray, nacreous appearance was discovered attached to the interior of an edible oyster while the author was enjoying a meal at home. The oyster had been purch
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
Gemological and Luminescence Characteristics of Taaffeites from Mogok, Myanmar
Taaffeite is a rare gem that has been found in different localities such as Tanzania, Sri Lanka, China, and Mogok, Myanmar. Systematic research on the taaffeite from Mogok, Myanmar
Quartz crystals from alpine fissures: their formation and the historical significance of alpine quartz as raw material for objets d’art
The central Alps, especially the central granite massifs (Aar Massif, Gotthard Massif, Mont Blanc Massif) in Switzerland and adjacent France are known since ancient times for their
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
Effects of weathering on FTIR spectra and origin traceability of archaeological amber: The case of the Han Tomb of Haihun Marquis, China
Amber (fossil resin), known as the “capsule of time and space”, which is a complex biogenic polymer originated from ancient plants resin from different geological periods [1].
DNA Fingerprinting and age dating of historic natural pearls: a combined approach
Natural pearls are accidental formations in wild oysters. The lack of new supply in recent decades has meant that the trade is heavily dependent on old stocks of natural pearls, an
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
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
Treated jadeite-jade: Unusually bright fancy colours
Jadeite-jade is a precious ornamental stone that has been valued as the topmost decorative stone and has been used in jewelry, carvings, and other ornamental objects by many cultur
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
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-