Summer 2020 Gems & Gemology | The Quarterly Journal of the Gemological Institute of America

EDITORIAL

Dive Into Summer: Yellow and Orange Diamonds, New Identification Techniques, and the Chronicles of Chivor

Duncan Pay, Editor-in-Chief

An overview of the Summer 2020 Gems & Gemology content.

COLOR

Naturally Colored Yellow and Orange Gem Diamonds: The Nitrogen Factorpresents the Four Major Groups of Defects Responsible for the Color in Nearly All Yellow and Orange Diamonds.

Presents the four major groups of defects responsible for the color in nearly all yellow and orange diamonds.

TECHNIQUES

Separation of Natural from Laboratory-Grown Diamond Using Time-Gated Luminescence Imaging

Researchers from De Beers Group Technology present a technique that expands on the surface luminescence used in the DiamondView instrument to provide additional imaging information and quickly distinguish colorless or near-colorless natural diamond from laboratory-grown diamond.

HISTORY

History of the Chivor Emerald Mine, Part II (1924–1970): Between Insolvency and Viability

Chronicles developments at the Chivor emerald mine in Colombia between 1924 and 1970, based on archival records.

TREATMENT PROCESS

Optical Whitening and Brightening of Pearls: A Fluorescence Spectroscopy Study

Presents a study that suggests optically brightened pearls can be consistently separated from non-brightened pearls using fluorescence spectroscopy.

TECHNIQUES

Hydrogen and Oxygen Stable Isotope Ratios of Dolomite-Related Nephrite: Relevance for Its Geographic Origin and Geological Significance

Examines the effectiveness of hydrogen and oxygen isotopes in discriminating dolomite-related nephrites from the four most important occurrences worldwide.

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