Nephrite jade with high market value and production potential from the Chinese city of Hechi, in Guangxi Province, was tested by standard gemological methods, polarizing microscopy, scanning electron ...

Diamond “type” is a concept that is frequently mentioned in the gemological literature, but its relevance to the practicing gemologist is rarely discussed. Diamonds are broadly divided into two types ...

The soothing soft pink shades of rose quartz appeal to gem carvers and collectors. – Valerie Power, courtesy Arunashi People accept a certain amount of sand, dirt, and dust as ordinary ingredients in ...

Whether you’re taking the next step in your professional journey or starting a new career, GIA courses and diploma programs prepare you for success. We offer the finest gem and jewelry education in ...

Many of the important gem minerals seen on today's market - aquamarine, tourmaline, and topaz, among others - come from an unusual type of rock known as a pegmatite. Gem-bearing pegmatites are ...

Colorless to yellow to intense orange sapphire will react quite differently to light or heat depending on the nature of the material and the origin of the color. The authors determined that there are ...

Figure 1. A zun (Chinese ritual wine vessel) ornately carved from Guangxi black nephrite in the form of a tiger squatting on all fours with a bird on its back. Photo courtesy of Hongwei Ma. In 2011, a ...

In November 2022, a parcel of 24 approximately 0.5–1.2 ct spinel crystals, described as cobalt-diffused, were obtained directly from a treater by the research team at GIA in Bangkok. Of these, seven ...

North America has a long history of natural pearling owing in part to its very diverse and rich freshwater mussel resources. After the Civil War pearl jewelry gained greater popularity in the United ...

Vietnam is a land of great diversity and beauty. From the hustle and bustle of Ho Chi Minh City to the beauty of Hạ Long Bay and Hoi An (both UNESCO World Heritage Sites), there are innumerable places ...

A parcel of sapphire and chrysoberyl from the Ilakaka-Sakaraha deposit in southern Madagascar. Photo by Vincent Pardieu, © GIA. Introduction In July-August 2010 and ...

Two specimens of faceted crystalized carbon - both are crystal clear and give off a kaleidoscope of spectral colors in direct light. They appear to be identical. One, however, is a billion or more ...