Fortieth Anniversary of the Belmont Mine

Marcelo Ribeiro offers an update on mining and cutting activities at the Belmont emerald mine in Brazil.

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Rex Guo: The Science and Art of Recutting Fine Gemstones

Rex Guo describes how he sources and systematically recuts faceted stones to unlock their inner beauty.

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Supply Chain Transparency and Beneficiation

Jean Claude Michelou shares his perspective on supply chain transparency and beneficiation in source countries.

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Unheated and Unusual Colors

Margit Thorndal of Madagascar Imports offers her perspective on the colored stone market.

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Quarterly Crystal: Cr-Diopside in Diamond

A bright green chromium diopside inclusion is seen in a diamond from South Africa's Kimberley mine.

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Type IIa Diamond with Extraordinary Etch Channels

Rare dissolution etch channels are seen in a natural diamond.

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Green Crystals in Yellow Sapphires

Two yellow sapphires yield surprising green inclusions.

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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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HPHT-Processed Diamond Fraudulently Represented as Untreated

An HPHT-treated round brilliant diamond with an inscription that presents as a GIA report number is found to be inconsistent with the institute's report, previously issued for an untreated diamond.

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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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Fracture-Filled Diamond with "Rainbow" Flash Effect

The material used to fill a large fracture in a diamond yields an unexpected iridescence under two different illuminations.

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Natural-Color Green Diamonds: A Beautiful Conundrum

Characterizes diamonds with exceptionally rare natural green color, based on GIA’s extensive database of samples.

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Iridescence in Metamorphic “Rainbow” Hematite

Analyzes the substructures that cause the intense iridescence observed in “rainbow” hematite from Minas Gerais, Brazil.

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DNA Techniques Applied to the Identification of Pinctada Fucata Pearls from Uwajima, Ehime Prefecture, Japan

Shows how genetic material extracted from small amounts of pearl powder can be a useful indicator of this akoya cultured pearl species.

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Non-Bead-Cultured Pearls from Pinctada margaritifera

A new report from GIA's Bangkok laboratory examines a set of 120 NBC samples stated to be of "Tahitian" origin.

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Non-Bead-Cultured Pearls from Pinctada margaritifera

A new report from GIA's Bangkok laboratory examines a set of 120 NBC samples stated to be of "Tahitian" origin.

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莫桑比克红宝石“低温”热处理研究进展:重点关注包裹体和傅里叶变换红外光谱

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New Developments and Opportunities for GIA Alumni Association Chapters and Members

A renewed structure, expanded education opportunities and other tools will help GIA Alumni Association chapters and members communicate GIA connection.

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M.D. Hohenstine 宝石陈列:使用未镶嵌的宝石创造流行橱窗艺术的过程

珠宝商 M.D. Hohenstine 令人惊艳的橱窗陈列是俄亥俄州哥伦比亚市中心一项备受欢迎的传统,拥有 50 多年的历史。

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宝石学家意欲激起全世界对巨大晶体的好奇心

‘Adventure seeker’ crawls through underground caves to reach and research giant selenite crystals – then shares her knowledge with the world.

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