News & Articles

CVD Diamond Over 34 Carats Examined in GIA’s Hong Kong Laboratory
A look at the largest CVD diamond GIA has encountered to date.
Read More
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.
Read More
An Update on Sapphires with Unstable Color
Unexpected behavior is observed in sapphires submitted to GIA for color stability testing.
Read More

Book Review: Pegmatites and Their Gem Minerals
Review of Pegmatites and Their Gem Minerals, by Michael Menzies and Jeffrey Scovil.
Read MoreView All Recent Articles