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 ...

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.

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 ...

Large quantities of rubies—both rough and faceted—from a commercially important new source in Myanmar (Burma) have been available on the Bangkok market since 1992. The ruby crystals from the Mong Hsu ...

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 ...

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 ...

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 ...

The names, home addresses, dates of birth and scans of valid government-issued photo identification for all owners or individuals who have 25% or more ownership or voting rights in the company or who ...

Established in 1931, the Gemological Institute of America (GIA) is the world’s foremost authority on diamonds, colored stones, and pearls. A public benefit, nonprofit institute, GIA is the leading ...

As a consumer, you will regularly encounter in the marketplace gems that have been treated to change their appearance. A topic that often comes up is whether a particular gemstone is or isn’t treated.

Trio of carved green tourmaline dolphins on frosted quartz base. Carved by Gerhard Becker. Gift of John Staver, GIA Collection. Photo by Orasa Weldon. In 1972, an immense pocket of superb tourmaline ...

GIA’s diverse course offerings will help prepare you with the knowledge and skills needed by industry employers today.