Gemological Characterization of Peridot from Pyaung-Gaung in Mogok, Myanmar

Examines the mining and the internal, spectroscopic, and chemical features of peridot from this deposit, which possesses a rich olive green color and is available in large sizes.

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Rainbow Graining in Diamond

One of the more subtle inclusion scenes gemologists sometimes observe in natural diamonds is the presence of crystallographically oriented structural defects known as “internal graining.”

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Blue Sapphires from Mogok, Myanmar: A Gemological Review

A gemological analysis of blue Burmese sapphires from Mogok, based on a series of field expeditions over the last decade.

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Colored Stones from the Deep

The first installment of this column discusses the formation of colored stones from the crust-mantle transition and below.

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Faceted Demantoid Garnet with Spectacular “Horsetail” Inclusions

Remarkable “horsetail” inclusions discovered in a demantoid garnet, while their origin and composition remain under discussion.

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Color-Zoned Cat’s-Eye Chrysoberyl

The Tokyo lab recently identified a unique localized distribution of cloud-like inclusions in a chrysoberyl.

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Spiral Nacre in Natural Pearl

Nacreous pearls are known to have platelet growth resembling fingerprints or topographic maps, but a less common appearance is nacre with a concentric spiral pattern.

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Two Antique Mughal Spectacles with Gemstone Lenses

Unique diamond- and emerald-lensed spectacles from the Mughal Empire were tested in GIA’s New York laboratory.

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Star Rhodochrosite

The Carlsbad lab received a rhodochrosite cabochon featuring rhomboid-shaped fluid inclusions, causing a four-rayed star.

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History of Emerald Mining in the Habachtal Deposit of Austria, Part I

Contributes to the mining history of Austria’s Habachtal region, which is believed to be one of the earliest emerald deposits.

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CVD实验室培育钻石大小刷新世界纪录

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Persian Turquoise: The Ancient Treasure of Neyshabur

Reports on the geology, background, and current state of mining and production at Iran’s largest turquoise mine.

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HPHT-Processed Diamond with Counterfeit GIA Inscription

Careful comparison of two GIA reports reveals a fraudulent inscription on a laboratory-produced diamond presented as a natural.

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New CVD Material Submitted for Analysis (英语)

A group of large, high-quality CVD material demonstrates the continued challenge of identifying laboratory-grown gems.

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Willemite in Topaz

A colorless topaz from Nigeria hosts the only known example of willemite as an inclusion in topaz.

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Internal Structures of Known Pinctada maxima Pearls: Cultured Pearls from Operated Marine Mollusks

A selection of 74 non-bead cultured and 12 bead cultured pearls grown in cultured pearl sacs and harvested directly from operated mollusks were collected and their internal structures examined using real-time microradiography and X-ray computed microtomography analyses.

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First Identification of Sudoite in Caribbean Ceramic-Age Lapidary Craftsmanship

Extensive analysis of early beads and pendants from archaeological sites in the French islands of the Lesser Antilles identified the objects as sudoite, which has never before been documented in any lapidary production.

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FTIR Observation on Sapphires Treated with Heat and Pressure

A study on heat with pressure treatment of blue sapphires reveals FTIR patterns associated with different iron concentrations.

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Fura Gems’ Inaugural Ruby Sale

Fura Gems hosted its first sales event for rough Mozambican rubies in August and September 2021.

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Heat Treatment Effects on the Behavior of the 3161 cm–1 Feature in Low-Iron Metamorphic Yellow Sapphire

This study examines FTIR spectra of yellow sapphire heat treated in an oxidizing atmosphere to deepen its color.

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