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Fluorescence Produced by Optical Defects in Diamond: Measurement, Characterization, and Challenges

How variations in UV lamp output can affect observed fluorescence color and intensity.

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Paula Crevoshay’s “Yogo Columbine” sapphire pendant
The Role of Silicon in the Color of Gem Corundum

Considers the previously unreported but critical impact of silicon on the coloration of gem-quality sapphire.

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Three cultured pearls, one natural
Real-Time Microradiography of Pearls: A Comparison Between Detectors

Compares the image quality provided by real-time microradiographic imaging (RTX) units fitted with two different detectors: an image intensifier (II) and a flat panel detector (FPD).

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Accurate Reporting of Key Trace Elements in Ruby and Sapphire Using Matrix-Matched Standards

Presents a group of corundum standards developed by GIA to improve the accuracy and efficiency of its laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) instruments.

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Five-strand Natural Pearl Necklace
X-ray Computed Microtomography: Distinguishing Natural Pearls from Beaded and Non-Beaded Cultured Pearls

The distinction of natural from cultured pearls traditionally has been based on X-radiography.

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Emerald crystals from Colombia, Afghanistan, and Zambia
Photoluminescence Spectra of Emeralds from Colombia, Afghanistan, and Zambia

Compares PL spectroscopy data of 48 emerald samples from three countries to evaluate the usefulness of the technique in geographic origin determination.

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A Mixture of Natural and Cultured Pearls
X-ray Computed Microtomography Applied to Pearls: Methodology, Advantages, and Limitations

X-ray computed microtomography reveals the internal features of pearls with great detail.

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Spectral Differentiation Between Copper and Iron Colorants in Gem Tourmalines
Spectral Differentiation Between Copper and Iron Colorants in Gem Tourmalines

The authors used Vis-NIR spectral measurements combined with LA-ICP-MS data to investigate the usefulness of absorption spectra.

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Green Amber
Characterization of “Green Amber” With Infrared and Nuclear Magnetic Resonance Spectroscopy

A peridot-like bright greenish yellow to green gem material called “green amber” has recently appeared in the gem market.

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Digital Photomicrography for Gemologists

A guide to capturing gem inclusion scenes using practical equipment and techniques and the appropriate image-refining software.

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