Past conferences
Abstracts Library
Causes of color in brown mammoth ivory
The mammoth species were once the largest terrestrial mammals in the world during the late Pleistocene (approximately 350,000 to 10,000 years ago), inhabiting the northern hemisphe
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
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
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
Milky appearance of Geuda sapphire from Sri Lanka
Sri Lanka is famous for gems since several thousand years. Almost corundum varieties have been found in Sri Lanka including the rough of Geuda which has also given considerable att
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
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
Rose Quartz: Journey Into the Nano-Jungle
Massive rose quartz is a readily available mineral ranging in colour from pink to salmon- or lavender-pink (Figure 1). Given its popularity in the market, it might be assumed that
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
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
CVD Rough Diamonds Striae Grading Approach based on Deviated Optical Performance of Polished CVD Diamonds
Diamond’s optical performance cognition and scientific descriptions are based on the three key attributes: brilliance, fire and scintillation. Brilliance is an illusion caused by
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
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
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
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
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
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
