Spectroscopic Characteristics of Low-Temperature Heated Blue to Violet Spinel

Although spinel is rarely treated, there have been some heated spinels available in the trade.

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James Shigley Receives Robert M. Shipley Award

Distinguished research fellow Dr. James Shigley receives the Robert M. Shipley Award for his contribution to the science of gemology.

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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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A Unique Double Cat’s-Eye Emerald

The Tokyo lab examined a stunning double cat’s-eye emerald whose chatoyancy was created both by its cut and its inclusions.

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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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Faceted Octahedral Diamond with Octahedral-Shaped Inclusion

Creative faceting highlights an octahedral-shaped cloud inclusion in a 2.01 ct diamond octahedron.

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Zircon with Unusual Color-Change Behavior

The Carlsbad laboratory recently had the chance to examine a 4.60 ct cushion-cut zircon with truly unusual color behavior.

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Laboratory-Grown Diamond with Internal Laser Markings

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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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Hematite “Rose” Inclusion in Aquamarine

Recently, a 23.67 ct pear cabochon aquamarine with light greenish blue color and poor clarity was sent to the Taiwan Union Lab of Gem Research (TULAB) for identification.

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Glass Imitation of Star Sapphire

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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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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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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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Fossilized Shell Consisting of Emerald

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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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Purple Gem Spinel from Vietnam and Afghanistan: Comparison of Trace Element Chemistry, Cause of Color, and Inclusions

Figure 1. The vivid colors seen in fine gem-quality spinel are derived from the mixing between multiple different chromophores in a range of ratios and concentrations, as in this fine 13.52 ct violetish purple spinel. Courtesy of the Dr. Edward J. Gübelin Collection. Photo by Robert Weldon/GIA.

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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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Pinctada maxima Pearls from Operated Mollusks, Sudoite in Ceramic-Age Caribbean Jewelry, Persian Turquoise Field Report, and More

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Dyed Non-Nacreous Pearls

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