Geographic Origin Determination of Emerald
Sudarat Saeseaw, Nathan D. Renfro, Aaron C. Palke, Ziyin Sun, and Shane F. McClure, January 31, 2020
The relative chemical diversity of emeralds from different deposits worldwide allows clear origin determination in most cases. This contribution explains the criteria used by GIA to make geographic origin conclusions for emeralds.
Read More
Chart: Inclusions in Natural, Synthetic, and Treated Ruby
Nathan D. Renfro, John I. Koivula, Jonathan Muyal, Shane F. McClure, Kevin Schumacher, and James E. Shigley, January 26, 2018
Provides a visual guide to the internal features of natural, synthetic, and treated rubies.
Read More
Chart: Inclusions in Natural, Synthetic, and Treated Emerald
Nathan D. Renfro, John I. Koivula, Jonathan Muyal, Shane F. McClure, Kevin Schumacher, and James E. Shigley, January 27, 2017
Provides a visual guide to the internal features of natural, synthetic, and treated emeralds.
Read More
Inclusions in Natural, Treated, Synthetic, and Imitation Opal
Nathan D. Renfro, John I. Koivula, Jonathan Muyal, Shane F. McClure, Kevin Schumacher, and James E. Shigley, August 15, 2019
Provides a visual guide to the internal features of natural, treated, synthetic, and imitation opal.
Read More
Geographic Origin Determination of Alexandrite
Ziyin Sun, Aaron C. Palke, Jonathan Muyal, Dino DeGhionno, and Shane F. McClure, January 31, 2020
The geographic source of this rare color-change gem has a significant impact on value. Trace element chemistry profiles allow GIA to accurately determine origin for alexandrite from several countries.
Read More
Black Diamonds from Marange (Zimbabwe): A Result of Natural Irradiation and Graphite Inclusions
Karen V. Smit, Elina Myagkaya, Stephanie Persaud, and Wuyi Wang, August 6, 2018
Characterizes a suite of 40 natural brown to black diamonds from this deposit so that they can be distinguished from suspected treated black diamonds.
Read More
Chart: Inclusions in Natural, Synthetic, and Treated Diamond
Nathan D. Renfro, John I. Koivula, Jonathan Muyal, Shane F. McClure, Kevin Schumacher, and James E. Shigley, February 1, 2019
Provides a visual guide to the internal features of natural, synthetic, and treated diamonds.
Read More
Gemological Characterization of Sapphires from Yogo Gulch, Montana
Nathan D. Renfro, Aaron C. Palke, and Richard B. Berg, August 6, 2018
A look at the mining and distinguishing characteristics of this naturally vibrant blue sapphire.
Read More
.png "Learn About NextGem")
