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A row of five low-quality bead cultured pearls.
Article
A Study on Improving the Surface Appearance of Low-Quality Pinctada maxima Bead Cultured Pearls

In this study, the Bangkok laboratory examined five low-quality bead cultured pearls sourced directly from a local pearl factory and characterised their features before and after processing.

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A white and purple pearl sitting in half of its shell.
Article
Clam Chowder with a Side of Pearl

Recently, GIA’s laboratory in New York had the opportunity to examine a fascinating pearl find and hear about an even more fascinating story.

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Faceted blue zircons
Reversible Colour 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 colour through the use of incandescent light.

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A piece of diamond rough with green body color and triangular etchings on the surface.
Article
GIA Researchers Reveal the Secrets of Diamond-in-a-Diamond Mystery

GIA researchers in New York recently had the opportunity to examine one of the most interesting and unique diamond crystals ever found.

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10.08 ct HPHT synthetic diamond with color equivalent to Fancy Deep blue
Blue HPHT Synthetic Diamond Over 10 Carats

Results from GIA’s recent testing of a 10.08 ct blue HPHT synthetic diamond, the largest HPHT synthetic recorded to date.

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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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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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HPHT-grown synthetic diamond melee.
Mixing of Natural Diamonds with HPHT Synthetic Melee

Screening reveals a surprise within a batch of synthetic diamond melee.

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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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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 recognised 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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