The Thai city of Chanthaburi is a well-known international trading hub for colored gemstones but was once an important corundum mining center. In recent decades, mining activity in the area has ...

Natural-color saltwater cultured pearls from Pinctada margaritifera were studied by diffuse reflectance UV-Vis-NIR spectroscopy to identify the absorption features associated with their various colors ...

This article examines the origins of gemstone treatment. Using such primary sources as Pliny's History and the relatively unknown Stockholm Papyrus, the author has uncovered many ancient references to ...

Africa was the major source of diamonds for most of the 20th century, but Australia and Sakha (of the Russian Federation) now produce about half the world’s supply. Also, most of the production today ...

“Ice jade” is a translucent variety of jadeite jade (also known as fei cui) that is generally of high value. Reportedly from the Morales mine in the Izabal Department of Guatemala, it has recently ...

A comprehensive look at Texas topaz, detailing its gemological and compositional characteristics and providing a basis for using trace element concentrations to identify its origin. Bohemian Garnets ...

Madagascar is one of the great wonders of our planet. Wim Vertriest, Manager of Field Gemology at GIA, takes us on a journey back in time to understand how the island acquired its incredible gemstone ...

CARLSBAD, Calif. – April 25, 2024 – Two leading gem and jewelry industry events will come together in September 2025, offering insight into cutting-edge gemological research, education, training and ...

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This large Australian light opal cabochon weighs 117.85 carats. Small play-of-color flashes of orange and green predominate in a pinfire pattern, with spots of a more muted blue over a grayish ...

Adjacent amethyst and citrine colors in the same crystal of quartz have been reported from South America, although there appears to be uncertainty as to the exact locality of origin. Such material has ...

Sapphires were recently found in alluvial deposits and in situ in basaltic rocks near Wutu, Changle County, in central Shandong Province. The fact that significant amounts of sapphire have been found ...