Welcome to 2016’s first Gems & Gemology!
The Tucson shows are renowned for showcasing nature’s finest gems and minerals. They’re also the venues to see imaginative use of gem materials in unfamiliar combinations. Our cover exemplifies this innovation with the “Wheel of Light”—a spectacular necklace featuring elements of sagenitic quartz, fire agate, Paraíba tourmaline, and braided leather, centered on a clear quartz disk wrapped with 24K gold. The rough gems and minerals placed inside the disk’s central axis reflect within the quartz to produce strikingly colored concentric bands. This piece amply demonstrates the ingenuity that makes the Tucson gem and mineral shows such refreshing and vital experiences. We hope you find this issue equally enjoyable.
We offer five feature articles on diverse topics: photoluminescence (PL) spectroscopy, Australian chrysoberyl, Italian serpentine, Tajikistan’s variscite, and treated “pistachio” cultured pearls from Tahiti. You’ll also find our latest Lab Notes and Micro-World entries, along with in-depth coverage of the February 2016 Tucson shows in our Gem News International section.
Drs. Sally Eaton-Magaña and Christopher M. Breeding of GIA’s Carlsbad lab are the authors of our lead article, which provides an overview of PL analysis and its increasing importance for detecting treatment, determining natural or synthetic origin, and verifying origin of color in type II diamonds. PL spectroscopy is now a vital tool for gemologists to authenticate the most valuable large or fancy-color gems.
Photoluminescence spectroscopy is now a vital tool to authenticate the most valuable diamonds.
In our second paper, a team of researchers led by Dr. Karl Schmetzer characterizes the gemological properties and growth structures of chrysoberyl recovered from the sapphire placer deposits in New South Wales, Australia.
Two other articles cover ornamental gem materials: First, Dr. Ilaria Adamo and colleagues offer a detailed mineralogical and gemological investigation of serpentine with gem potential from Pizzo Tremogge in Val Malenco, Italy. Next, Dr. Andrey Litvinenko and his coauthors report on a largely untapped source of the ornamental mineral variscite in central Tajikistan.
Finally, Dr. Chunhui Zhou and his team from GIA’s New York lab document the identification of treated pistachio-colored cultured pearls produced by the Ballerina Pearl Co.
We also offer hearty congratulations to the winners of the 2015 Dr. Edward J. Gübelin Most Valuable Article Award. We’re delighted with the fantastic response to our reader ballot, which showed a significant increase in participation over last year—a big “thank you” to everyone who voted. Also, don’t forget to take this year’s G&G Challenge, our annual multiple-choice quiz.
Please enjoy the Spring issue!