Black Diamonds from Marange (Zimbabwe): A Result of Natural Irradiation and Graphite Inclusions
Characterises a suite of 40 natural brown to black diamonds from this deposit so that they can be distinguished from suspected treated black diamonds.
Natural-Colour Blue, Grey and Violet Diamonds: Allure of the Deep
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.
Saltwater Pearls from the Pre- to Early Columbian Era: A Gemmological and Radiocarbon Dating Study
Examines 85 saltwater natural pearls, reportedly harvested from the Caribbean islands off the coast of Venezuela during the early 16th century, to determine their age.
Cutting Diffraction Gratings to Improve Dispersion (“Fire”) in Diamonds
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.
A Foundation for Grading the Overall Cut Quality of Round Brilliant Cut Diamonds
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.
The Wittelsbach Blue
This article describes what is known about the Wittelsbach Blue since it was first reported in 1666, and the gemmological information released to date on this diamond.
Grey-To-Blue-To-Violet Hydrogen-Rich Diamonds from the Argyle Mine, Australia
The Argyle diamond mine is the only known source of type IaB hydrogen- and nitrogen-rich diamonds coloured grey to blue to violet.
Developments in Gemstone Analysis Techniques and Instrumentation During the 2000s
The first decade of the 2000s continued the trend of using more powerful analytical instruments to solve gem identification problems.
CVD Synthetic Diamonds from Gemesis Corp
An examination of the gemmological and spectroscopic properties of CVD synthetic diamonds from Gemesis Corp.
Celebrating 75 Years of Gems & Gemology
Gems & Gemology, the professional quarterly of GIA, debuted in 1934