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Iridescent arrowhead needles
Article
Characterization of Blue Sapphires from the Mogok Stone Tract, Mandalay Region, Burma (Myanmar)

The Mogok Stone Tract of central Myanmar (Burma) is one of the world’s most famed sources of colored stones, particularly ruby, sapphire, and spinel.

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Pinctada margaritifera (black-lipped pearl oyster) shells together
Article
Non-Bead-Cultured Pearls from Pinctada margaritifera

A new report from GIA's Bangkok laboratory, "Non-Bead-Cultured Pearls from Pinctada margaritifera," examines a set of 120 NBC samples stated to be of "Tahitian" origin.

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Article
Update on "Low-Temperature" Heat Treatment of Mozambican Ruby: A Focus on Inclusions and FTIR Spectroscopy

GIA's Bangkok laboratory recently performed heat treatment experiments on 47 Mozambican rubies mined in Mugloto.

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

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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Rough and cut sapphires
Article
A Study of Sapphire from Chanthaburi, Thailand and its Gemological Characteristics

A report from the GIA Laboratory in Bangkok presents their findings on 59 blue sapphire samples obtained from a miner in the Khao Ploy Waen area, Chanthaburi.

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Article
Atypical “Beading” in the Production of Cultured Pearls from Australian Pinctada Maxima

In 2011, the authors began to see cases of low-quality natural pearls being used as unconventional “beads” for cultured nacre growth.

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Blue Sapphires
Article
An In-Depth Gemological Study of Blue Sapphires from the Baw Mar Mine (Mogok, Myanmar)

GIA field gemologists visited Baw Mar operations in 2013, 2014, and 2015. In this study, we analyzed samples collected during two separate expeditions.

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Blue sapphires
Article
An In-Depth Gemological Study of Blue Sapphires from Pailin, Cambodia

A report from GIA Laboratory in Bangkok analyzing 68 blue sapphires from Pailin, Cambodia.

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Synthetic Ruby Overgrowth on Natural Corundum
Article
Analysis of Synthetic Ruby Overgrowth on Corundum

Analysis of synthetic ruby overgrowth on corundum, using analysis of inclusions, UV-Vis-NIR and EDXRF spectroscopy, and LA-ICP-MS.

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Cambodian-Thai Ruby
Article
A Study of Rubies from Cambodia and Thailand

A report from the GIA Laboratory in Bangkok analyzing 41 Cambodian-Thai rubies.

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