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 ...

Reviews the advancements and major trends in laboratory-grown diamonds observed by GIA since 2007. Gemological and Trace Element Characteristics of Cassiterite from Yunling, China Examines gem-quality ...

The 75.47-carat Hooker Emerald was worn by Ottoman Sultan Abdul Hamid II, the last sultan of the Ottoman Empire. Photo by Chip Clark, courtesy Smithsonian Institution, National Museum of Natural ...

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Ruby is the July birthstone – and it’s one of the most coveted of gems. The name is derived from the Latin word ruber, meaning “red” – the color of love and passion. Few things catch the eye like the ...

Blue diffusion-treated sapphires are becoming more prevalent than ever before. The diffusion technique, which involves the addition of color-causing chemicals during heat treatment, results in a thin ...

Aquamarine has been treasured through the ages, and with proper care will give its owner a lifetime of pleasure. - Courtesy Jeffrey Appling Hardness and toughness Gem and mineral hardness is measured ...

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 ...

GIA is the world’s most trusted name in diamond grading and gem identification. With objectivity and expertise as its hallmarks, GIA ensures the integrity and accuracy of every report it issues. GIA ...

With a reach that spans the globe, GIA is a nonprofit institute dedicated to protecting consumers by ensuring their trust in gems and jewelry through cutting edge gemological research, rigorous ...

GIA’s laboratory in Bangkok, Thailand conducts research and provides services such as diamond grading and origin determination, colored stone grading and origin determination and pearl identification ...

This selection of gems from Ouro Prêto, Brazil, and Russia's Ural Mountains, displays the golden orange to pinkish red color range of precious topaz. The gems range from 7.61 to 14.33 carats in size.