Thailand has long been famous for its gems, as it is an important source for many types of gems, such as, the ruby, corundum, topaz, zircon, garnet, and mother of pearl. Thus the Thai gem and adornment industry has received praise both in terms of quality and price from all over. Indeed, gems and adornment are a major Thai export, and is expected to even increase each year.
The x-ray absorption spectroscopy technique employed by SLRI’s 8th beam line is especially efficient for atomic and compound analysis that are of very low quantity in nature. The beautiful colorations of the gems result from the type of mineral and the compound and atomic structure of the various elements diffused in the crystal. Since some of the mixtures of elements vital to coloration are of extremely low quantity and difficult to detect using general methods, x-ray absorption spectroscopy enables such analysis, extending even to determining the oxidation states of the atom of interest. Thus it is possible to find the elemental and compound components that affect the color and beauty of each type of gem. In the gem industry today, there is always the search for methods to improve the quality of the gem such as more regular diffusion of color, more glitter and subsequently, more beauty. Some existing methods consist of heat treatment, color diffusion, irradiation, dyeing, foil back, and gem cutting. Each method has its own effect towards the beauty of gems.
Besides employing synchrotron light to study components for better understanding of the beauty of the gem, x-ray absorption spectroscopy has a major role in studying the changes in the atomic structure wrought by these methods, as to approach the ideal process for improving the quality of the gems for even more beauty and acceptability.
The 8th Beamline Research Group has been working on increasing value for the Thai gemology industry. They have been working closely with Ajahn Sorapong Pongsekrapan, Kasetsart Researcher, on using x-ray absorption to study the sapphire; the color changing process of the ruby; understanding the factors affecting the color of topaz, as well as searching for elements that play a role in color changing of the black pearl, for example. Using the x-ray absorption technique to study pearls, the researchers discovered a research innovation to produce gold pearls as well as to imprint gold on the pearl using synchrotron light. This innovation will enable the fresh water pearl, usually of low price, to be transformed into a golden pearl that is beautiful and distinguished, efficiently for the very first time in the world. Dr. Nirawat Thammajakr leads the Golden Pearl Production Prototype Project using synchrotron light.
Transforming the white fresh water pearl into gold preserves its natural beauty, and can increase its glitter as gold. The new technology for transferring gold designs onto the pearl for a one-of-a-kind beauty enhancement can provide details on the micrometer level (even smaller than a strand of hair), so that the resulting pearl becomes a gift of great price for that one and only important person.