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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

10月生まれの方は、誕生日を祝福するのに2つの素晴らしい誕生石、オパールとトルマリンをお楽しみいただけます。10月の誕生石は、両方とも無限の色の組み合わせを持ち、美しい色を ...

The locality origin of natural-color blue sapphires from Kashmir can, in many cases, be positively identified. However, the field of origin determination is a very complex one – especially with the ...