Metrology, the science of measurement and its application, plays a critical role in the accuracy of GIA’s research and laboratory services. The metrology team closely monitors the performance of ...

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 ...

Jade is one of the most misunderstood gemstones. It is actually two separate materials: jadeite and nephrite. Together, these materials have more simulants than most other gems. Thus, it is important ...

Birthstones are a fun, popular and colorful introduction to the world of gemstones. They appeal to audiences around the world regardless of gender, age, nationality or religion. Birthstones carry ...

Figure 1. This alexandrite cabochon appears brownish green in fluorescent light (left) and brownish purple in incandescent light (right). The cabochon shows chatoyancy under both forms of illumination ...

Observations of Oval-, Pear-, and Marquise-Shaped Diamonds: Implications for Fancy Cut Grading Presents findings from observations of oval-, pear-, and marquise-shaped diamonds, laying the groundwork ...

With decades of expertise and laboratory locations worldwide, GIA uses more advanced instrumentation that extends far beyond the boundaries of standard gemological testing. The comprehensive analysis ...

Secure your spot for the Sept. 7-10 event in Carlsbad, CA CARLSBAD, Calif. – January 27, 2025 – Registration for Converge, the singular gem and jewelry event combining the unique expertise of the ...

CARLSBAD, Calif. – January 29, 2025 – GIA field gemologists recently completed their one-hundredth expedition, adding to the Institute’s unrivaled store of independently verified gemological ...

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 ...

Harness the power of knowledge with the industry-leading instruments that GIA uses in its grading laboratories. Representing more than 85 years of research and the combined expertise of GIA’s ...

Pink-to-red coral has a long history as an ornamental gem material in jewelry, carvings, and sculptures. However, due to a variety of environmental and legal factors, the supply of high-quality, ...