Phenomenal Sinkankas Symposium

In April this year, the San Diego Mineral and Gem Society, along with the Gemological Institute of America, hosted the fourth annual John Sinkankas Symposium. Sinkankas (1915–2002), a renowned mineral collector, gemologist, and author of many works, including Mineralogy for Amateurs, three volumes of Gemstones of North America, and Gem Cutting: A Lapidary’s Manual, is remembered by these annual gatherings.

The sold-out event brought gem and mineral experts, master cutters, and gem and jewelry photographers and writers together for a day of insightful lectures about phenomenal stones. Topics included chatoyancy, asterism, adularescence, change-of-color, and play-of-color. Photographing, collecting, cutting, and evaluating phenomenal gemstones also were discussed.

There to share their wisdom were noted gem experts Si Frazier; Dr. George Rossman, professor of mineralogy, California Institute of Technology; John Koivula, chief research gemologist, American Gem Trade Association; Fred Ward, author and photographer; and Robert Weldon, GIA’s new photography and visual communications manager.

More than 200 rough and cut phenomenal gems, provided courtesy of Bill Larson and Pala International, were on display.

“The seminar was a wonderful mix of scientists, collectors, cutters, and photographers who each provided firsthand insight into a specific aspect of these special gems,” said GIA Museum curator Terri Ottaway. “I came away with a whole new appreciation of the causes of the optical phenomena and the difficulties cutters and photographers face when dealing with them.”