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the quarterly journal of the gemological institute of america
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the quarterly journal of the gemological institute of america
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Internal Structures of Natural Pearls from Pinctada maxima, Identification of Resin-Filled Turquoise, Spinel Inclusions Chart, and More……
Duncan Pay, Editor-in-Chief
An overview of the Spring 2021 Gems & Gemology content.
Articles (4)
![Organics](https://www.gia.edu/images/SP21-Homkrajae-Fig2-VRL265226-216px.jpg)
Internal Structures of Known Pinctada maxima Pearls: Natural Pearls from Wild Marine Mollusks
Presents the internal characteristics of natural P. maxima pearls, obtained from real-time microradiography (RTX) and X-ray computed microtomography (µ-CT) analysis of 774 samples.
Read More![Treatment Process](https://www.gia.edu/images/SP21-Li-Fig1AB-VRL265241-216px.jpg)
Technical Evolution and Identification of Resin-Filled Turquoise
Provides criteria for detecting the resin filling of turquoise, an advanced treatment that reduces porosity and can dramatically improve appearance and stability.
Read More![Color](https://www.gia.edu/images/SP21-Shen-Fig1-VRL265155-216px.jpg)
How to Calculate Color from Spectra of Uniaxial Gemstones
Presents a method for accurately predicting the color of a gem material when viewed in any direction as long as the polarized spectra and the viewing angle relative to the c-axis are known.
Read More![Inclusions](https://www.gia.edu/images/SP21-Renfro-article-Fig1-VRL265308-216px.jpg)
Micro-Features of Spinel
Provides a visual guide to the internal features of natural, synthetic, and treated spinel, as well as inclusions of spinel in other gemstones.
Read MoreRegular Features
![Lab Notes](https://www.gia.edu/images/lab-notes-landing-page-300x169.jpg)
![Cloud inclusion resembling the profile of a faceted diamond.](https://www.gia.edu/images/SP21-MW-Fig3-VRL265295-216px.jpg)
![Gem News](https://www.gia.edu/images/gni-landing-page-300x169.jpg)
Gem News International
Global coverage of gem sources, notable new gem materials, and recent industry developments.
View All (20)Most Valuable Article Awards
A Quantitative Description of the Causes of Color in Corundum
Emily V. Dubinsky, Jennifer Stone-Sundberg, and John L. Emmett
History of the Chivor Emerald Mine, Part I (1880–1925): From Rediscovery to Early Production
Karl Schmetzer, Gérard Martayan, and Jose Guillermo Ortiz
Naturally Colored Yellow and Orange Gem Diamonds: The Nitrogen Factor
Christopher M. Breeding, Sally Eaton-Magaña, and James E. Shigley
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past gems & gemology issues
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