GIA developed this guide so retailers can use fluorescence tests to help identify gems right in their own stores.

A guide describing frequently encountered gem treatment processes, their detection, and special care tips for treated gems.

Established in 1931, the Gemological Institute of America (GIA) is the world’s foremost authority on diamonds, colored stones, and pearls. A public benefit, nonprofit institute, GIA is the leading ...

Turquoise ranks 5 to 6 on the Mohs hardness scale. Hardness and toughness Gem and mineral hardness is measured on the Mohs scale. The numbers are based on the relative ease or difficulty with which ...

Tanzanite is one of the most popular colored gemstones in the world.- Courtesy Tanzanite Foundation ™ Tanzanite is a versatile gemstone that comes in a variety of sizes and cutting styles. Although it ...

Attractive yellow to light greenish yellow gem scapolites have been mined from a skarn deposit near the town of Ihosy, in southern Madagascar, since the late 1990s. Chemical analysis indicates that ...

GIA studied more than 400 important gemstones from the Gübelin Collection and is committed to sharing this repository of gemological information. This work is a valuable resource for all students, ...

Feature Gems & Gemology, Fall 2014, Vol. 50, No. 3 Observations on Pearls Reportedly from the Pinnidae Family (Pen Pearls) Nicholas Sturman, Artitaya Homkrajae, Areeya Manustrong, and Nanthaporn Somsa ...

A new type of African chalcedony with the trade name “Aquaprase” shows unique composition and attractive color.

Stability Alexandrite is stable under normal wearing conditions, which means it’s resistant to the effects of heat, light, and common chemicals. Cleaning Warm, soapy water is always safe for cleaning ...

Identification challenges related to Chemical Vapor Deposition (CVD) synthetic diamonds ...

Synthetic moissanite is much closer to diamond in overall appearance and heft than any previous diamond imitation; this article reports on how to identify and characterize it.