Figure 1. These emeralds from Musakashi, Zambia, range from 0.57 to 4.85 ct. The rough samples were polished with one window on each. The faceted sample measures 6.29 × 5.35 × 3.53 mm and weighs 0.97 ...

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 ...

CARLSBAD, Calif. – April 7, 2025 – In response to logistics challenges related to recently announced tariffs affecting global shipments of gemstones, GIA (Gemological Institute of America) will ...

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 ...

People from all over the world send their diamonds to the GIA laboratory for grading and analysis. Our clients put their business in our hands and their trust in our expertise – and we are extremely ...

Gem and mineral hardness is measured on the Mohs scale. The numbers are based on the relative ease or difficulty with which one mineral can be scratched by another. But the Mohs scale is deceptive.

This 3.74-ct. princess-cut aquamarine’s prized medium-blue color is highlighted by the 22 diamonds that surround it. The ring is an original, copyrighted design by Zoltan David. - Robert Weldon, ...

The even, deep blue color of this lapis lazuli cabochon is rare and highly prized by connoisseurs. Lapis lazuli is treasured the world over for its beautiful deep blue color. Variously described as ...

Opal was first discovered in Ethiopia in the early 1990s. Specimens from Mezezo in the historical Shewa province consist of nodules of a reddish brown volcanic rock with orange, reddish brown, or ...

Diamonds have a long history as beautiful objects of desire. In the first century AD, the Roman naturalist Pliny stated: “Diamond is the most valuable, not only of precious stones, but of all things ...

Diamond is available in a range of sizes and qualities to fit every consumer's tastes. One of the first things most people learn about diamonds is that not all diamonds are created equal. In fact, ...

Online courses and Lab classes required to earn your online credential offered via the GIA Online Division are listed below. Click here to download the requirements ...