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5.19 ct CVD synthetic diamond
CVD Synthetic Diamond Over 5 Carats Identified by GIA

Results from GIA’s recent testing of a 5.19 ct CVD synthetic diamond, the largest it has examined to date.

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Aquamarine from San Luis Potosí State in northern Mexico
Aquamarine from a New Primary Deposit in Mexico

Examination of aquamarine samples from a new primary deposit in San Luis Potosí, northern Mexico.

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Faceted blue zircons
Reversible Color Modification of Blue Zircon by Long-Wave Ultraviolet Radiation

Determines whether blue zircon, inadvertently altered to brown by exposure to long-wave UV radiation, can be restored to its original color through the use of incandescent light.

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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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A 0.11 ct faceted grandidierite from Madagascar
A New Deposit of Gem-Quality Grandidierite in Madagascar

Reviews the properties of exceptionally pure grandidierite from a new source.

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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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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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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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