Observations on HPHT-Grown Synthetic Diamonds: A Review
Summarizes statistical data and distinctive features of several thousand gem-quality HPHT synthetic diamonds examined by GIA from 2007 through 2016.
Saltwater Pearls from the Pre- to Early Columbian Era: A Gemological 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.
True Colors of “Dalmatian Jasper”
Discusses the mineralogical composition and provenance of this spotted decorative gemstone.
Synthetic Star Sapphires and Rubies Produced by Wiede’s Carbidwerk, Freyung, Germany
Details the process used by Wiede’s Carbidwerk to produce star synthetic corundum from the mid-1950s through the 1970s.
Photoluminescence Spectra of Emeralds from Colombia, Afghanistan, and Zambia
Compares PL spectroscopy data of 48 emerald samples from three countries to evaluate the usefulness of the technique in geographic origin determination.
The Latest on Synthetic Diamonds
Dr. James Shigley, GIA distinguished research fellow, is one of the foremost experts in diamonds and their identification. In this presentation recorded at the 2017 JCK Las Vegas show, he shares the latest developments about HPHT and CVD synthetic diamond
Variscite from Central Tajikistan: Preliminary Results
A look at the gemological properties and chemical composition of this light blue to light green to green gem material, which is suitable for cabochon cutting.
Photoluminescence Mapping of Optical Defects in HPHT Synthetic Diamond
Demonstrates the importance of this method in identifying diamond treatments, based on the analysis of PL maps acquired from a brownish orange HPHT synthetic diamond.
Observations on CVD-Grown Synthetic Diamonds: A Review
Explores statistical data and defining characteristics of gem-quality CVD synthetic diamonds examined by GIA since 2003.
Identification of “Pistachio” Colored Pearls Treated by Ballerina Pearl Co.
A report on the color treatment process for these intensely greenish yellow to yellowish green cultured pearls and the techniques for identifying them.