A chemical and spectroscopic comparison of two purple gem spinel samples, one of them the first reported example of a spinel with a saturated purple color caused predominantly by chromium and cobalt.

View the holiday schedule for all GIA locations worldwide.

Reports on a visit to a shell nucleus manufacturer and two pearl farms in northern Vietnam, which is emerging as a notable producer.

ABSTRACT Aquamarine and heliodor are colored by Fe ions, an important coloring agent for beryl. Blue to yellow gem beryl was studied by quantitative spectroscopy and trace-element analytical ...

New York laboratory receives resubmission of HPHT-treated diamond that changed from a dark yellowish brown to a deep yellow-orange during treatment.

Diamonds have a long history as a premier gemstone—a natural consequence of their beauty, rarity, and superlative physical properties such as extreme hardness. Diamonds that are mined for use as ...

Learn more about what causes a diamond to chip, and 8 tips on how you can avoid chipping your diamond.

Sri Lanka’s gemstone and jewelry industry blends traditional practices and experience with the needs of the modern global market. Photo by Andrew Lucas/GIA. To visit Sri Lanka is to experience one of ...

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 ...

A gemological investigation into natural moldavite and its more recent imitations.

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

Journey with us to Brazil for a visit to one of the world’s most prolific tourmaline mines. You’ll also hear a highly captivating story of family success through perseverance.