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Fancy Dark brown to Fancy black Marange diamonds
Black Diamonds from Marange (Zimbabwe): A Result of Natural Irradiation and Graphite Inclusions

Characterizes a suite of 40 natural brown to black diamonds from this deposit so that they can be distinguished from suspected treated black diamonds.

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Timeline showing the use of garnets in different eras from 300 BCE to 700 CE
An Early Byzantine Engraved Almandine from the Garibpet Deposit, Telangana State, India: Evidence for Garnet Trade Along the Ancient Maritime Silk Road

Analyzes the chemical composition and inclusion characteristics of this ancient artifact.

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Recently discovered and legendary diamonds in the blue/gray/violet color range
Natural-Color Blue, Gray, and Violet Diamonds: Allure of the Deep

Summarizes data collected on more than 15,000 natural blue/gray/violet diamonds examined by GIA during the last decade and examines the mechanisms that produce this color range.

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Aquamarine, Maxixe-Type Beryl, and Hydrothermal Synthetic Blue Beryl: Analysis and Identification

Aquamarine, Maxixe-type (irradiated) beryl, and two types of hydrothermally grown synthetic blue beryl currently available in the marketplace were investigated by various gemological methods.

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An exceptionally large and clean 1.91 ct faceted oval brilliant afghanite.
Large Faceted Afghanite

A report on the largest facet-grade afghanite seen in the GIA gem identification department.

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The repaired diamond.
A Repaired Diamond

A marquise-cut diamond is found to have been broken and reassembled with an unknown adhesive.

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Major colors of HPHT synthetic diamonds
Observations on HPHT-Grown Synthetic Diamonds: A Review

Summarizes statistical data and distinctive features of several thousand gem-quality HPHT synthetic diamonds examined by GIA from 2007 through 2016.

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Irradiated 1.06 ct brownish orange HPHT synthetic diamond
Photoluminescence Mapping of Optical Defects in HPHT Synthetic Diamond

Demonstrates the importance of this method in identifying diamond treatments, based on the analysis of PL maps acquired from a brownish orange HPHT synthetic diamond.

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Near-colorless and Fancy Vivid purplish pink CVD synthetic diamonds
Observations on CVD-Grown Synthetic Diamonds: A Review

Explores statistical data and defining characteristics of gem-quality CVD synthetic diamonds examined by GIA since 2003.

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Fluorescence image of Aurora Butterfly of Peace
An Introduction to Photoluminescence Spectroscopy for Diamond and Its Applications in Gemology

Presents the underlying physics and methodology of this analytical technique, which has become an essential tool in identifying treated and synthetic diamonds.

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