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Explore the mesmerizing world of agate — from its varieties to jewelry uses and sources. Uncover the secrets of these stunning gemstones!

Learn essential ruby buying tips from experts. Discover how to evaluate color, clarity, cut & carat weight. Avoid synthetic stones & treatments.…

Next to diamond, corundum is the hardest mineral known and is very compact and dense, with no cleavage. As a result, corundum is one of the best of…

Some opals from Spencer, Idaho show asterism or the “star stone” effect. Learn how to price these beautiful but rare star opals.

Turkey’s gemstones include well-known species such as diaspore, chalcedony, and purple jade, as well as unusual specimens of lesser-known gems.…

Learn about the different crystal growth methods used to artificially create gemstones in laboratories.

Learn about synthetic diamond creation and the challenges buyers face determining whether a diamond is natural or artificial.

Many varieties of gems besides diamond can be created in the laboratory. Our synthetic gemstone guide covers many examples and explains their…

Whether you’re an expert or novice gemologist or collector, add these gemology reference books we’ve reviewed to your library.