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 ...

Not all Russian demantoids have these famous chrysotile inclusions. Horsetails are also seen in demantoids from Iran and Italy but not in those from Namibia or Madagascar.

Fine-color, large, and eye-clean (lacking visible inclusions) rubies like this 11.01carat (ct) stone from Myanmar (formerly known as Burma) are extremely rare and valuable. – Photo: Robert Weldon/GIA.

This sapphire from Kashmir has an intense velvety blue color. – Photo: Robert Weldon/GIA. Sapphire is one of the Big three of jewelry colored gemstones—the other two are ruby and emerald. A durable ...

Emerald, the birthstone for May, has been beloved for millennia, evoking rebirth and renewal. Widely regarded as the definition of green, emerald is the perfect color for spring. From the poetic ...

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 ...

Figure 1. A single tourmaline fiber contains three distinct chemical zones, each recording the fluid composition at the time of growth. Between zones, fluids dissolved preexisting tourmaline to ...

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.

A GIA Report is not a guarantee, valuation or appraisal, and GIA makes no representation or warranty regarding its Reports, the articles described therein or any inscription thereon. A GIA Report ...