Past conferences
Abstracts Library
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
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
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
The Importance of Research for Gem & Jewellery Industry
Research has always been an essential tool for business leaders who always realise that the consuming public is active, and hence, research investment could help lead their busines
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
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.
Proposed New Filler Type for Emerald Fracture Filling: Design, Detection, Differentiation, Disclosure
Fracture filling is common in gem trading to enhance gemstones’ beauty and / or durability. Common textbook examples are (lead) glass filling of rubies and diamonds, polymer/resi
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
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
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
Gemmological studies of “Hybrid Diamond” (Natural + CVD synthetics)
Size and quality of CVD synthetic diamonds for jewelry market have been improved over the years, and various fancy colour CVD diamonds have also been produced. In addition, overgro
Crystal structure of nano inclusions in blue sapphire from Diego Suarez, Northern Madagascar
Nano inclusions in unheated blue sapphire (Diego Suarez, northern Madagascar) containing naturally occurring beryllium have been studied. Tabular nano inclusions with a diameter of
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
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
Diamonds and synthetic diamonds
Diamond is historically one of the most important gemstones, in terms of value, use and general appreciation. Diamonds were generally formed relatively early in the Earth’s Histo
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
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
The Banjarmasin Diamond in Amsterdam – War Booty from Borneo
The Banjarmasin diamond in the collection of the Rijksmuseum in Amsterdam plays a questionable role in the history of the Dutch occupation of Southern Borneo. Confiscated from the
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-