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 ...

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 ...

Pietersite has been described as a brecciated variety of tiger’s-eye. This study examined pietersite specimens from Namibia and China (the main sources) using powder X-ray diffraction, optical ...

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 ...

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 ...

GIA’s laboratories use advanced instrumentation and research to deliver accurate grading, identification, and origin ...

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 ...

3月の2つの誕生石であるアクアマリンとブラッドストーンは全く異なって見えますが、幸福をもたらすという共通の効果を持っています。アクアマリンの誕生石からは海の色が思い浮かびます。

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 ...

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, ...

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 ...