Kimberlites: Earth’s Diamond Delivery System
Examines the basic characteristics of kimberlites and their relationship with diamonds.
A Decade of Ruby from Mozambique: A Review (英语)
Reviews the mining history, market impact, and properties of ruby from northern Mozambique near Montepuez, now the world’s most productive source.
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.
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.
Inclusions in Natural, Treated, Synthetic, and Imitation Opal
Provides a visual guide to the internal features of natural, treated, synthetic, and imitation opal.
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.
Gemological and Chemical Characteristics of Natural Freshwater Pearls from the Mississippi River System
GIA had the unique opportunity to study the gemological and chemical characteristics of 854 natural freshwater pearls from the Mississippi River system.
The Effect of Low-Temperature Heat Treatment on Pink Sapphire
Twelve pink sapphires undergo low-temperature heat treatment and reveal a correlation with the 3232 cm-1 FTIR peak.
A Special Type of Trapiche Quartz
Three incomplete trapiche quartz make up this interesting sample.
Tagua Nut as a Sustainable Botanical Alternative for Ivory
Jewelry designer Alexandra Mor uses sustainable alternatives for elephant ivory.
Gem Art of the Taj Mahal, Fancy White and Black Diamonds, and Unique Inclusions in Thai Corundum
An overview of the Fall 2019 Gems & Gemology content.
Dive Into Summer: Mozambique Ruby, Madagascar Sapphire, and Black Nephrite from China, Plus an Opal Inclusions Chart
An overview of the Summer 2019 Gems & Gemology content.
Plume Agate from Iran
Two varieties of colorful plume agates, characterized by inclusions resembling clouds of smoke, are sourced from Iran.
Iridescent Tabasco Geode
Tabasco geodes are a small geode variety named for the area where they are mined in the Mexican state of Zacatecas, near the city of Tabasco.
Quarterly Crystal: Dioptase in and on Quartz
Crystals of transparent colorless rock crystal quartz play host to a wide variety of mineral inclusions, some of which are highly attractive.
Summer 2019 G&G: Mozambican Ruby, Challenges in Pearl Identification, and an Opal Inclusions Chart
An overview of the Summer 2019 Gems & Gemology content.
Euhedral Phantom Sapphire in Sapphire
A phantom sapphire crystal within a host sapphire crystal was recently examined at GIA’s Carlsbad laboratory.
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