The French Blue and the Hope: New Data from the Discovery of a Historical Lead Cast
With the use of modern tools and technology, this article sheds light on the history and provenance of both the French Blue and the Hope diamonds.
Ruby and Sapphire Production and Distribution: A Quarter Century of Change
During the past 25 years, the corundum market has been transformed from one of medium to high-priced gems to one that encompasses nearly all price ranges.
Begin with the End in Mind: Tips, Tools to Evaluate Diamond Rough
Guest speaker Chandra Horn shares the challenges artisanal miners face evaluating the quality of diamond rough and some tools to make it easier.
Characterizing Natural-Color Type IIB Blue Diamonds
More than 400 blue diamonds were studied at the GIA Gem Trade Laboratory over several years to reveal additional information about the relationships between their color, clarity, and other gemological properties.
The Impact of Internal Whitish And Reflective Graining on the Clarity Grading of D-To-Z Color Diamonds at the GIA Laboratory
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-color diamonds.
Color Grading “D-to-Z” Diamonds at the GIA Laboratory
This article discusses the history and ongoing development of GIA's color grading system, and explains how its laboratory applies it.
Unusual Dumbbell-Like Inclusion in Diamond
Examination of a 0.40 ct near-colorless round brilliant diamond with a large inclusion resembling a dumbbell
Very Large CVD-Grown Synthetic Diamond
The New York laboratory recently tested a 2.16 ct CVD synthetic from Scio Diamond Technology Corp., the largest specimen GIA has seen so far.
Spectroscopic Evidence of GE POL HPHT-Treated Natural Type IIA Diamonds
Results from spectroscopic analyses of GE POL high-pressure high-temperature (HPHT) annealed nominally type IIa diamonds are presented, and these spectral characteristics are compared with those of untreated diamonds of similar appearance and type.
Diopside Needles as Inclusions in Demantoid Garnet from Russia: A Raman Microspectrometric Study
Straight, acicular, colorless solid inclusions in demantoid garnet from the Ural Mountains of Russia were investigated by laser Raman microspectrometry.