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 ...

GIA will offer convenient access for colored stone identification and identification and origin laboratory services at the show. Drop off your stones for expert analysis and report services in the ...

CARLSBAD, California – January 14, 2025 - The Gemological Institute of America (GIA) has announced the planned retirement of its president and CEO, Susan Jacques, at the end of 2025. The Institute has ...

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, ...

The GIA Laboratory-Grown Diamond Report includes full quality assessment with a plotted clarity diagram. Color and clarity specification are described on the same scale as the GIA Diamond Grading ...

A new production of hydrothermal synthetic emeralds, grown in the Czech Republic with Italian technology, has been marketed since December 2004 with the trade name Malossi synthetic emerald. Several ...

Amethyst may develop into the more common citrine and rarer green quartz naturally under certain geologic conditions. On the California-Nevada border, just north of Reno, amethyst, citrine, and green ...

Adjacent amethyst and citrine colors in the same crystal of quartz have been reported from South America, although there appears to be uncertainty as to the exact locality of origin. Such material has ...

Diamond color is all about what you can’t see. Diamonds are valued by how closely they approach colorlessness – the less color, the higher their value. (The exception to this is fancy color diamonds, ...

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 ...

Commercial quantities of gem-quality benitoite are known from a single location in the world, the Benitoite Gem mine in the New Idria district of San Benito County, California. A barium titanium ...