GIA ensures accurate gemological measurements across its global laboratories through rigorous metrology practices, including systematic instrument calibration, validation from traceable standards, and ...

Using a multi-step process, Lucent Diamonds has developed a new treatment process for certain natural diamonds that creates colors from pink-purple through red to orangy brown.

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 ...

The northeastern portion of the state of Minas Gerais, Brazil, contains the world's greatest concentration of complex granitic pegmatites, which are especially noted for the production of gem beryl, ...

When microscopic identification is not feasible, FTIR spectra at high resolution (0.5 cm^–1) can distinguish natural and synthetic amethyst.

View the holiday schedule for all GIA locations worldwide.

Conch "pearls" are calcareous concretions produced by the Queen conch mollusk, Strombus gigas, which is found in various areas of the Caribbean. Although conch"pearls" occur in a range of colors, the ...

A behind-the-scenes exploration of the Smithsonian's Janet Annenberg Hooker Hall of Geology, Gems, and Minerals.

Natural pearl identification is one of the critical problems in pearl research. The DNA study of pearly mollusks and oysters facilitates solving this problem. To fulfill this goal, GIA sent a group ...

Lightning Ridge is the world capital of fine black opals, the most desired of all opals. In June 2015 a group of GIA field gemologists visited this legendary town in New South Wales, Australia. Come ...

What exactly are man-made diamonds? Find out how they compare to natural diamonds and what you should know.

Figure 1. A view of the pink sapphire mining pit at Kibuko, in the Uluguru Mountains of Tanzania. Photo by Vincent Pardieu/GIA. A team of GIA field gemologists visited Tanzanian mines in the summer of ...