the quarterly journal of the gemological institute of america
In This Issue
A Decade of Ruby from Mozambique: A Review
Madagascar Sapphire: Low-Temperature Heat Treatment Experiments
Black Nephrite Jade from Guangxi, Southern China
Evidence of Rotation in Flame-Structure Pearls from Bivalves of the Tridacnidae Family
A Pearl Identification Challenge
Inclusions in Natural, Treated, Synthetic, and Imitation Opal
Previous Issue
the quarterly journal of the gemological institute of america
Dive Into Summer: Mozambique Ruby, Madagascar Sapphire, and Black Nephrite from China, Plus an Opal Inclusions Chart
Duncan Pay, Editor-in-Chief
Articles (6)
A Decade of Ruby from Mozambique: A Review
Reviews the mining history, market impact, and properties of ruby from northern Mozambique near Montepuez, now the world’s most productive source.
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Madagascar Sapphire: Low-Temperature Heat Treatment Experiments
Shows how the color of Madagascar sapphire is lightened with heating to relatively low temperatures below 1350°C.
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Black Nephrite Jade from Guangxi, Southern China
Characterizes black nephrite from a deposit in the Guangxi region that appears to be part of a large-scale jade formation belt in southern China.
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Evidence of Rotation in Flame-Structure Pearls from Bivalves of the Tridacnidae Family
A study of these pearls to characterize their distinctive flame structure and examine the possibility of rotation during their formation or growth.
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A Pearl Identification Challenge
Two pearls presented a unique challenge, as testing at three different gemological laboratories could not conclusively identify them as natural or cultured, determine a freshwater or saltwater growth environment, or specify the producing mollusk.
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Inclusions in Natural, Treated, Synthetic, and Imitation Opal
Provides a visual guide to the internal features of natural, treated, synthetic, and imitation opal.
Read MoreRegular Features
Gem News International
Global coverage of gem sources, notable new gem materials, and recent industry developments.
View All (9)
Diamonds From the Deep
Explores the role of diamonds in our understanding of the natural world.
View All (1)
MOST VALUABLE ARTICLE AWARD
The Color Origin of Gem Diaspore: Correlation to Corundum
Che Shen and Ren Lu
Gemological Characteristics of Sapphires from Yogo Gulch, Montana
Nathan D. Renfro, Aaron C. Palke, and Richard B. Berg
Natural-Color Green Diamonds: A Beautiful Conundrum
Christopher M. Breeding, Sally Eaton-Magaña, and James E. Shigley
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