Spring 2015 - Volume 51, Issue 1
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Gemstones

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Color-treated chameleon diamonds
Artificially Irradiated Color-Change Diamonds

Examination of two chameleon diamonds reveals color enhancement through artificial irradiation.

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Diamond within black diamond
Diamond in Diamond

A Fancy black round brilliant diamond has an inclusion that is revealed to be a natural diamond crystal.

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Bracelet with moissanites
Synthetic Moissanite Melee in a Colored Diamond Bracelet

The New York lab discovers synthetic moissanite in a colored diamond bracelet.

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Colorless round brilliant melee
Analysis of Melee Diamonds Using FTIR Spectroscopy

GIA’s New York lab uses newly developed protocol to identify the origin of melee diamonds.

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Melee-set pendant
HPHT Synthetic Diamond Melee in High-Quality Jewelry Piece

The New York lab discovers a synthetic melee diamond in a pendant, underscoring the importance of testing for undisclosed synthetics.

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Purple quahog pearl
Large Natural Quahog Pearl

A purple non-nacreous specimen is revealed to be a natural northern quahog pearl.

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Tridacna shells
Conservation Concerns over Use of Tridacna Shell in Imitation Pearls

The New York lab investigates the use of the shells of Tridacna species as imitation pearls.

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Pink and Reddish Purple Cobaltocalcite Specimens
Pink and Reddish Purple Cobaltocalcite

GIA's Bangkok lab investigates the coloration and gemological properties of this striking mineral specimen.

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two large synthetic diamonds
Large HPHT-Grown Synthetic Diamonds Examined in GIA’s Hong Kong Laboratory

Examination of the largest HPHT synthetic diamonds GIA has examined so far demonstrated significant progress in this growth technology.

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