The Winter 2017 issue of Gems & Gemology (G&G), GIA’s (Gemological Institute of America’s) quarterly professional journal, explores the deep geologic origins of the world’s biggest and purest diamonds and what they tell us about the earth; the Dreher family of gem carvers of Idar-Oberstein; the first characterization of Australian akoya cultured pearls; recent improvements in GIA’s reference standards for trace element analysis; and a comparison of two X-ray microradiography detectors. It also contains a wall chart of inclusions in natural, treated and synthetic ruby. The issue is available in print by subscription and in the GIA Store, and digitally – at no cost – on GIA.edu.

G&G opens with “The Very Deep Origin of the World’s Biggest Diamonds.” GIA research scientist Dr. Evan Smith, Dr. Steven Shirey of the Carnegie Institution for Science and Dr. Wuyi Wang, GIA’s vice president of research and development, co-authored the cover article. Their work expands on research presented in the December 2016 issue of Science magazine, in which Dr. Smith and a team of researchers uncovered how Cullinan-like, nitrogen-poor “CLIPPIR” diamonds contain inclusions that offer insight into the nature and formation of the Earth’s mantle. The G&G article provides more detail on the key features of these diamonds as well as data on additional samples.

“Gem Virtuosos: The Drehers and Their Extraordinary Carvings” explores the work of a multigenerational family of gem carvers, the Drehers of Idar-Oberstein, Germany. Robert Weldon, Cathleen Jonathan and Rose Tozer of GIA’s Richard T. Liddicoat Library and Information Center focus on the contemporary craft of Gerd Dreher and his son, Patrick, who create elegant gem carvings from high-quality agate and other rough gem materials.

Research by Dr. Laura Otter and coauthors is presented in “Akoya Cultured Pearl Farming in Eastern Australia.” This is the first gemological characterization of Australian akoya cultured pearls using Raman, photoluminescence, FTIR and UV-Vis spectroscopy.

Additional articles cover new developments in industry techniques: Dr. Jennifer Stone-Sundberg’s “Accurate Reporting of Key Trace Elements in Ruby and Sapphire Using Matrix-Matched Standards” and Dr. Stefanos Karampelas’s “Real-Time Microradiography of Pearls: A Comparison Between Detectors.”

The Winter 2017 issue of G&G also features a wall chart on ruby inclusions, the third in a series of charts on gem inclusions. The same team of specialists that created G&G’s Winter 2016 emerald inclusion chart and the Summer 2017 sapphire inclusion chart, led by GIA’s Nathan Renfro and John Koivula, documents a range of internal features found in natural, treated and synthetic ruby. Laminated versions of all three charts may be purchased at the GIA Store.