(Follow this link for abstracts of past issues)

ABSTRACT
This paper describes a preliminary study dealing with the detection of elements in gemstones using the Laser Induced Breakdown Spectroscopy (LIBS) method. The purpose of this project was, first, to investigate the overall performance of the LIBS method for detecting beryllium (Be), lithium (Li) and boron (B) in selected nontreated and treated corundums heated by the author in his thermochernical lab in Bangkok, and second to expand the testing process for detecting different elements in different gemstones.

The elemental analyses of these specimens were performed with a bench-lab type LIBS configuration setup. Laser sparks, fired onto the surface of test specimens by focused pulses from a laser produced plasma that had distinct spectral emission signatures which are captured by a spectrograph and processed by a computer. All observations and testing procedures were recorded. The ionic emission lines of Be, Li, and B, as well as the atomic lines of aluminum (Al), were detected and numerous spectrograms were produced. Detection limits of Be, Li and B in corundum, damage assessment of the specimens, measurement parameters, laser energy, signal interference, calibration, and other issues were investigated.

The results of this preliminary study emphasize the fact that the LIBS method can detect Be, Li, B and other elements in gemstones, provided that the current qualitative measurement tolerance of error (-20~~o) could he considerably reduced. It is also emphasized that this study is a preliminary account of the applications of LIBS in gemmology, and verification of the facts uncovered in this investigation must be substantiated by future experiments.

CHEMICAL COMPOSITION AND MINERALOGICAL PROPERTIES 
OF A PINK TOURMALINE MINERAL FROM PEGMATITES AROUND 
RAJGARH, AJMER DISTRICT, RAJASTHAN, INDIA

Liaqat A K Rao, S. Rehan Ali, Preeti Singh
Department of Geology, Aligarh Muslim University, Aligarh, India

ABSTRACT
The Pre-Aravalli Formation, which has been intruded by pegmatites and ultrabasics, shows the occurrence of tourmaline at the village Rajgarh in Ajmer District. The presence of tourmaline was established through optical, chemical and thermal studies. The chemical composition of this pink elbaite, in wt% is SiO₂ (38.12), Al₂O₃ (41.2), B₂O₃ (11.6), TiO₂ (0.02), Fe₂O₃ (0.06), FeO (0.08), MnO (0.23), CaO (0.75), MgO (0.23), U₂O (1.51), Na₂O (2.4), K₂O (0.25), H₂O+ (3. 1), H₂O (0.18), and F (0.95). The structural formula for this elbaite, computed on the basis of 31 (0, OK F) is (OH, F)_3.64 (Fe₂, Fe₃, Mg, Ca, Mn, Na, K, Li,Ti,AI)_3.53 (Si, B, Al _15.13 (O)_26.74.

IN THE PINK: ARGYLE’S GIFT TO AUSTRALIA

THE KASUMIGAURA PEARL™

Boris Dilenburger
Perlen Yukie GMBH

ABSTRACT
Kasumigaura pearLS™are natural coloured, Bead nucleated freshwater pearls that have been cultured in and around Lake Kasumigaura in a hybrid of Japanese and Chinese freshwater mussels. In this paper the author describes the origins of freshwater pearl culture in Japan, before providing an explanation of how Biwa pearl culture was relocated to Lake Kasumigaura, and refined by years of research to produce the Kasumigaura pearl™. Available details on the identifying characteristics of these relatively rare and expensive cultured pearls also are provided.

ABSTRACT
Vietnamese research in geology has indicated a high potential for gemstones in Vietnam, and has found in this last decade, numerous gem deposits, especially ruby and sapphire. In northern Vietnam, gem corundums are found in the Luc Yen, Yen Bai and Quy Chan areas, in primary deposits hosted by metamorphic rocks and in placers. In secondary deposits, ruby and sapphire are associated with gem spinel and garnet. In southern Vietnam, sapphires are related to alkaline basalts, with blue sapphires being of economic significance. Sapphires are recovered with gem zircons and peridots in placers. Aquamarine, beryl, topaz, quartz crystals (amethyst, citrine, morion), tektite, fluorite, opal, chalcedony, jadeite, nephrite and amazonite are the other gemstones exploited in Vietnam. Ruby, sapphires and pearls provide important commercial exchanges in the gemstones markets of Vietnam and other foreign countries.

NEW DEPOSIT OF GEM QUALITY COLOUR-CHANGE DIASPORE FROM MÖNG HSU, MYANMAR

U Hla Kyi, Kyaw Khaing Win
Yangon, Myanmar

ABSTRACT
This brief report describes a new find of gem-quality colour change diaspore crystals from Mong Hsu, Myanmar. More than 20 specimens of diaspore, with colours of pale green, purple and purplish red, were found. Diaspore aggregates associated with green tourmaline and ruby also were found.

SAPPHIRE IN BASALT FAKE

Terry Coldham
Sapphex, Sydney

ABSTRACT
A brief description sapphire in matrix specimen, allededly from P.R. China, that was purchased at the 2004 Tucson Show by the author.