Sapphire Beneath the Rich Black Soil of Muling, Northeastern China
A comprehensive look at the gemological features and advanced analysis of blue and fancy-color sapphire from the agricultural area of Muling, China.
Breyite Inclusion in Diamond
A breyite inclusion suggests the sublithospheric origin of a diamond examined in GIA’s New York laboratory.
Fall 2022 G&G Available Now
Book Review: Pegmatites and Their Gem Minerals
Review of Pegmatites and Their Gem Minerals, by Michael Menzies and Jeffrey Scovil.
Book Review: Pegmatites and Their Gem Minerals
The Geographic Origin of Diamonds, Sapphire from China, and Pigments Sourced from Gem Materials
An overview of the Fall 2022 Gems & Gemology content.
Inclusions in Gemstones
This installment of “Colored Stones Unearthed” explores inclusions in gems—how they form, how they are studied, and what they mean for gemologists and geoscientists.
A Look at Diamonds and Diamond Mining in Guyana
Reports on diamonds from Guyana’s alluvial deposits, including mining history and practices.
A Zircon with Strong Photochromic Effect
Photochromic zircon shows significant color change from medium light greenish blue to very dark yellowish green.
A Gemological and Spectroscopic Study with Mobile Instruments of “Emeralds” from the Coronation Crown of Napoleon III
An examination of 45 gems from the coronation crown of Napoleon III, using nondestructive mobile spectroscopic and gemological testing methods.
The Type IIb De Beers Cullinan Blue Diamond
GIA’s New York laboratory reports on a 15.10 ct Fancy Vivid blue cut-cornered rectangular step cut named the De Beers Cullinan Blue diamond.
The Shape of Ekanite
Discusses the unusual surface characteristics of ekanite from secondary deposits in Sri Lanka.
Diamonds from Guyana, Ekanite from Sri Lanka, a New Amber Source in Vietnam, and More...
An overview of the Summer 2022 Gems & Gemology content.
A Large Aquamarine with Unusual Etch Features from Xinjiang, China
Unique natural etch pattern and dissolution cavities are observed in a large aquamarine crystal.
Brilliance Exhibit at the Natural History Museum of Los Angeles County
A glimpse at the rare gems recently on display at the Natural History Museum of Los Angeles County’s Brilliance: The Art and Science of Rare Jewels exhibit.
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