News & Articles

Color Modification of Spinel by Nickel (Ni) Diffusion: A New Treatment in the Gem Market
GIA researchers report on a new nickel-diffusion treatment used to modify color in spinel and present criteria for identification.
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An Update on Sapphires with Unstable Color
Unexpected behavior is observed in sapphires submitted to GIA for color stability testing.
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Book Review: Pegmatites and Their Gem Minerals
Review of Pegmatites and Their Gem Minerals, by Michael Menzies and Jeffrey Scovil.
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