More on Spectroscopy of Yellow Diamonds

I read with interest “Characterization and grading of natural-color yellow diamonds” by John King and collaborators in the Summer 2005 issue (pp. 88–115). It is an informative text putting together a lot of useful gemological and spectroscopic data. I was a little surprised in reading the description of Group 2 that this category of yellow diamonds was not recognized as belonging to the “brown to grayish-yellow family” of hydrogen-rich diamonds defined by myself, Ken Scarratt, and Alan Collins in 1991 (see E. Fritsch et al., “Optical properties of diamonds with an unusually high hydrogen content,” in R. Messier et al., Eds., Materials Research Society International Conference Proceedings, 2nd International Conference on New Diamond Science and Technology, Washington, DC, Sept. 23–27, 1991, Materials Research Society, Pittsburgh, PA, pp. 671–676; E. Fritsch and K. Scarratt, “Gemmological properties of type Ia diamonds with an unusually high hydrogen content,” Journal of Gemmology, Vol. 23, No. 8, 1993, pp. 15–24). The brownish yellow color is well within the range described by the family name, and the color of such stones extends all the way to brown (B. M. Laurs, “Gem News International: International Geological Congress,” Gems & Gemology, Vol. 41, No. 1, 2005, pp. 67–69).

Nevertheless, I was delighted to learn that this category is so prominent among yellow diamonds (the second most common after “cape” stones, representing about 4% of submitted diamonds). This demonstrates that what might be perceived as a curiosity when first described may later turn out to be of larger significance.

Emmanuel Fritsch
IMN, University of Nantes, France

In Memoriam: Alfred A. Levinson (1927–2005)

Gems & Gemology mourns the loss of Dr. Alfred A. Levinson, professor emeritus of geology at the University of Calgary. A longtime contributor, reviewer, and editor for G&G, Dr. Levinson passed away December 12 at the age of 78.

Al Levinson was born and raised in Staten Island, New York, and became interested in geology at a young age. He attended college for a year before enlisting in the Navy in 1945. After the war, he used his G.I. Bill benefits to attend the University of Michigan, where he received a Ph.D. in mineralogy in 1952.

After working as an assistant professor of mineralogy at Ohio State University in the mid-1950s, Dr. Levinson spent the next 10 years in private industry, conducting mineral exploration with Dow Chemical Co. and petroleum studies for Gulf Research and Development Co. In 1966, he proposed a system of mineral nomenclature for rare-earth elements that was accepted by the International Mineralogical Association in 1971 and to this day is widely known as the Levinson system. In 2002, the mineral species levinsonite-(Y) was named in his honor.

Eager to return to academia, Dr. Levinson accepted a professorship at the University of Calgary in 1967. From 1967 to 1970, he also served as executive editor of Geochimica et Cosmochimica Acta, even as he was preparing the Proceedings of the Apollo 11 Lunar Science Conference (1970) and the Proceedings of the Second Lunar Science Conference (1971). During the 1970s and 1980s, he published two textbooks on geochemistry.

Dr. Levinson turned to gemology late in his career, and was particularly active after becoming a professor emeritus in 1994. He was an acknowledged expert on the occurrence, exploration, recovery, and economics of diamonds. Among the 10 feature articles he coauthored for Gems & Gemology were some of the most important diamond papers in the journal’s history. Three received Most Valuable Article awards: “Age, origin, and emplacement of diamonds: Scientific advances in the last decade” (Spring 1991); “Diamond sources and production: Past, present, and future” (Winter 1992); and “Diamonds in Canada” (Fall 2002). He also contributed a chapter on diamond sources to The Nature of Diamonds (1998), edited by Dr. George Harlow.

Al Levinson meant many things to Gems & Gemology. He was a mainstay of the editorial review board since 1995 and the editor of the Gemological Abstracts section since 1997. And for the past three years, he carefully reviewed the final set of page proofs for each issue before publication. Yet his importance to G&G went beyond his intellectual contributions. Above all, Al was a beloved friend and a constant source of support and encouragement for the entire staff. He will be greatly missed.