The Panyu district is a leading gemstone cutting and jewelry manufacturing center for the global gem and jewelry industry. Situated near Hong Kong, it plays a key role in jewelry exports from mainland ...

Previously we touched upon the basic science of sapphire —its mineralogy, chemistry, and physics—and also its appeal as a gemstone and in some industrial applications. Having looked at the first ...

Ancient Indians called it “the king of precious stones.” Burmese warriors thought it made them invulnerable in battle. Medieval Europeans believed it cured hemorrhages and inflammatory diseases. The ...

Zircon is rated 6 to 7.5 on the Mohs scale. It has fair to good toughness. While zircon is not as hard or tough as a stone like sapphire, it can still be worn in all types of jewelry as long as proper ...

Within a short time, 90 more claims appeared in the same 20-square-mile area. No one was quite sure what the beautiful crystals were, but everyone wanted to lay claim to the profits they were certain ...

Birthstones are a fun, popular and colorful introduction to the world of gemstones. They appeal to audiences around the world regardless of gender, age, nationality or religion. Birthstones carry ...

The quarterly journal of the Gemological Institute of America.

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Fortunately, the identification of faceted moldavite is simple. Besides their flow texture and abundant bubbles (almost always much more abundant than in an artificial glass), moldavites contain ...

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.

Search GIA's library catalog of 65,000 books, 230,000 images, 2200 videos, 1200 periodicals, and the renowned Cartier Rare Book Repository and Archive.

This 6.30-carat black boulder opal from Queensland, Australia, displays vivid play-of-color. Black opals are highly valued because their dark body tone showcases play-of-color more dramatically than ...