Karen V. Smit, Elina Myagkaya, Stephanie Persaud, and Wuyi Wang, August 6, 2018
Characterises a suite of 40 natural brown to black diamonds from this deposit so that they can be distinguished from suspected treated black diamonds.
Read MoreSally Eaton-Magaña, Christopher M. Breeding, and James E. Shigley, August 6, 2018
Summarises data collected on more than 15,000 natural blue/grey/violet diamonds examined by GIA during the last decade and examines the mechanisms that produce this colour range.
Read MoreAl Gilbertson, Benjamin Gudlewski, Mary Johnson, George Maltezos, Axel Scherer, and James Shigley
A new microlithography process developed to create high-resolution diffraction grating patterns on portions of certain facets can improve the dispersion of light and thus the amount of “fire” in a diamond.
Read MoreThomas M. Moses, Mary L. Johnson, September 1, 2004
The GIA diamond cut grading system described here includes the components of brightness, fire, scintillation, polish and symmetry, as well as weight and durability concerns, into a single overall grade for cut quality for standard round brilliants.
Read MoreWuyi Wang, Ulrika F. S. D’Haenens-Johansson, Paul Johnson, Kyaw Soe Moe, Erica Emerson, Mark E. Newton, and Thomas M. Moses, June 1, 2012
An examination of the gemmological and spectroscopic properties of CVD synthetic diamonds from Gemesis Corp.
Read MoreChristopher M. Breeding and James E. Shigley, June 1, 2009
Knowledge of type allows gemmologists to better evaluate if a diamond might be treated or synthetic, and whether it should be sent to a laboratory for testing.
Read MoreJohn M. King, December 1, 2006
This article reviews the GIA Laboratory’s history of reporting on certain types of graining which are often the only characteristics present in large, high-clarity, high-colour diamonds.
Read MoreC. W. Fryer and John I. Koivula, June 1, 1986
Several famous and historical gemstones in the Smithsonian's collection are examined and reported on.
Read MoreRon H.Geurts, Ilene M. Reinitz, Troy Blodgett, and Al M. Gilbertson, December 1, 2011
A presentation of parameters used to support GIA's symmetry grading system.
Read MoreJohn M. King, December 1, 2008
This article discusses the history and ongoing development of GIA's colour grading system, and explains how its laboratory applies it.
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