MORE ON SYNTHETIC CORUNDUM “GEM ROUGH”
The report on synthetic corundum "gem rough" in Tanzania (Winter 2006 Gem News International, p. 282) is both interesting and helpful, and Mr. Farooq Hashmi is kind to alert the industry and provide these samples for analysis. However, I would add that though laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) is wonderful when it is accessible, simple pocket instruments such as rare-earth magnets can instantly provide useful information for those dealing gems in remote locations.
By applying the magnetic separation approach that I presented at last summer’s Gemological Research Conference in San Diego (see the Fall 2006 Gems & Gemology, p. 124) to distinguish between spessartine rough and orange sapphire rough, gem dealers might avert this potentially costly misrepresentation. Mn-rich spessartine generally can be characterized by a relatively strong magnetic response, using the direct or pendulum method. Though not diagnostic, the lack of such a response (as with sapphire) could quickly flag this material as something other than spessartine.
Your readers may find the magnetic separation table in the G&G Data Depository helpful; there is also a related article in the Winter 2006 Canadian Gemmologist (S. Gumpesberger, “Magnetic separation of gemstones,” Vol. 27, No. 4, pp. 120–124).
Sylvia Gumpesberger
Canadian Gemmological Association, Toronto, Ontario
FALL 2006 ISSUE REQUIRED READING
Unaccustomed as I am to writing letters of this kind—especially to G&G—scientific integrity compels me to acknowledge and commend your Fall 2006 issue.
As one unable to attend, I found your coverage of the 4th International Gemological Symposium extremely interesting.
On the other hand, your 2006 GIA Research Conference was simply outstanding. The information imparted both by the speakers and through the poster presentations should be required reading for all who would call themselves gemologists.
Keep up the good work.
Dr. W. Wm. Hanneman
Poulsbo, Washington
IN MEMORIAM: DAVID HARGETT (1953–2007)
Gemologist and author David Hargett passed away recently in New York, the city he called his home for most of his adult life. He was 53. Dave worked for the GIA Laboratory in New York for 16 years as a colleague of current GIA Laboratory Senior Vice President Tom Moses and their gemological mentor G. Robert Crowningshield. Dave began his career with GIA in January 1977 after obtaining his Graduate Gemologist (G.G.) diploma in Santa Monica, Calif., followed later by a bachelor’s degree from New York University.
At the East Coast GIA Laboratory, Dave served for several years as manager of the Gem Identification Department, where he was instrumental in developing many of the techniques still used today to recognize synthetic and treated colored stones, as well as cultured pearls and enhanced diamonds. The author or co-author of many Gems & Gemology Lab Notes on unusual gem materials, in 1989 he also co-authored the award-winning Koivula et al. article on “The Characterization and Identification of Filled Diamonds.” Dave was very fond of gemologically related travel, and he particularly enjoyed exploring the gem mining areas of Mexico and Central America. In its Summer 1990 issue, G&G published Dave’s definitive paper on the jadeite deposits of Guatemala. Dave left GIA in 1992 and started his own consulting business, which allowed him to focus on areas of gemology he had come to enjoy.
Those who were fortunate enough to know Dave Hargett as a friend remember him as a kind and generous person with an amazing sense of humor. Those who worked with him in his chosen profession remember him as an excellent gemologist with a keen and curious mind. Through his dedicated gemological research and an overall strong work ethic, he gained the respect and admiration of gemologists all over the world. He will be missed by many, both within and outside the gemological community.
