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552.7 ct Yellow Diamond from the Diavik Mine
The Largest Diamond Ever Discovered in North America

GIA examines a 552.7 ct diamond from the Diavik mine in Canada.

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Natural diamond with CVD synthetic diamond overgrowth
CVD Layer Grown on Natural Diamond

A composite of synthetically grown and natural diamond was recently identified by the Carlsbad laboratory.

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Article
Observations on the Heat Treatment of Basalt-Related Blue Sapphires

Researchers from GIA’s Bangkok laboratory seek to identify low-temperature heat treatment in basalt-related blue sapphires.

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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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Suite containing over 36 carats of Yogo sapphire
Gemological Characterization of Sapphires from Yogo Gulch, Montana

A look at the mining and distinguishing characteristics of this naturally vibrant blue sapphire.

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CVD- and HPHT-grown synthetic diamonds.
Features of Synthetic Diamonds

Presents a visual guide to the growth processes and major gemological spectroscopic features of synthetic diamonds.

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Natural blister in the form of a pearlfish.
Natural Blister from Entombment of a Pearlfish Within a Pinctada Maxima Shell

A blister in a P. maxima shell, formed when the mollusk's nacre covered a trapped pearlfish, preserves the fish in stunning detail.

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Recently submitted 3.52 ct. CVD-grown diamond.
Five CVD Synthetic Diamonds Greater Than Three Carats

The GIA lab examines five gem-quality CVD-grown diamonds in sizes that reflect the improving technology of the synthetic gemstone industry.

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Cat's-eye demantoid with well-aligned horsetail inclusions.
Cat's-Eye Demantoid and Brown Andradite with Horsetail Inclusions

The examination of two unusual garnets results in identifications issued for the first time in GIA's colored stone report records.

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Pearls, shells, and jewelry on table
Article
The Lure of American Freshwater Pearls: Revisiting the Latendresse Family

John Latendresse is known as the father of American cultured pearls. He was also a great natural pearl collector and left his family a remarkable natural pearl collection. The Latendresse family is well recognized in the American pearl industry and has long supported GIA pearl research. Come with us to revisit this family and their pearl collection.

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