the quarterly journal of the gemological institute of america
Winter 2025 - Volume 61, Issue 4
All Issuesthe quarterly journal of the gemological institute of america
Intriguing Sapphire from Montana, a New Source of Emerald in Central China, and Arkansas Turquoise
Duncan Pay, Editor-in-Chief
An overview of the Winter 2025 Gems & Gemology content.
Articles (3)
The Primary Sapphire Occurrence at French Bar Sill Along the Missouri River, Near Helena, Montana
Reports on a new source of primary gem-quality sapphire from Montana, comparing its inclusions and trace element chemistry with those from secondary sources in the state.
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Characterization of Emeralds from Zhen’an County in Shaanxi, China
Presents a comprehensive analysis of the gemological, spectroscopic, and trace element characteristics of a set of Shaanxi emerald samples based on standard and advanced gemological methods.
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An Evaluation of Turquoise from the Mona Lisa Mine in Arkansas
Examines samples of Mona Lisa turquoise to identify their chemistry and structure, revealing copper as a major elemental component of the material.
Read MoreRegular Features
Gem News International
Global coverage of gem sources, notable new gem materials, and recent industry developments.
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Colored Stones Unearthed
Explores the geological concepts related to colored stone formation.
View All (1)Special Features
In the Spotlight
A photo tour of the GIA Museum’s latest exhibit featuring extraordinary crystals and gems central to the cultures of southern Asia.
Most Valuable Article Awards
Laboratory-Grown Diamonds: An Update on Identification and Products Evaluated at GIA
Sally Eaton-Magaña, Matthew F. Hardman, and Shoko Odake
Observations of Oval-, Pear-, and Marquise-Shaped Diamonds: Implications for Fancy Cut Grading
Ilene M. Reinitz, Al Gilbertson, Troy Blodgett, Amanda Hawkes, James Conant, and Abhijith Prabhu
Chemical Analysis in the Gemological Laboratory: XRF and LA-ICP-MS
Ziyin Sun, Michael Jollands, and Aaron C. Palke
the archive
past gems & gemology issues