The Winter 2007 issue of the Gemological Institute of America's Gems & Gemology, available now, reports on the newest commercially available chemical vapor deposition (CVD) synthetic diamonds, plus vivid yellow tourmaline from Zambia and much more.
In the lead article, "Latest-Generation CVD-Grown Synthetic Diamonds from Apollo Diamond Inc.," Dr. Wuyi Wang and a team of researchers report on the properties of these new products. Now marketed in colorless, near-colorless, and fancy-color varieties, they show significant improvements in size, color, and clarity over the samples examined by GIA in 2003. The article describes the unusual internal graining and birefringence, complex fluorescence zoning, and spectroscopic features that characterize the material.
"With recent advances in CVD synthesis, Apollo's latest lab-created diamonds are comparable in color and clarity to natural diamonds in the marketplace," said G&G Editor-in-Chief Alice S. Keller. "This article by Dr. Wang and colleagues is an essential guide to consistent identification of CVD synthetic diamonds."
In "Yellow Mn-rich Tourmaline from the Canary Mining Area, Zambia," Brendan Laurs and coauthors explore the world's most important source of this vivid elbaite. They present a gemological characterization and geologic investigation of the "canary" tourmaline, which is notable for its high manganese and low iron content.
Next, Dr. Sally Eaton-Magaña, et al.'s "Fluorescence Spectra of Colored Diamonds Using a Rapid, Mobile Spectrometer" examines the application of fluorescence spectroscopy to help characterize fancy-color diamonds. In this study, the fluorescence spectra of the natural-color diamond samples tested generally corresponded to bodycolor. The article also illustrates the potential of the inexpensive, portable charge-coupled device (CCD) spectrometer for characterizing fluorescence and phosphorescence in diamond.
The Winter issue lineup also includes "An Examination of the Napoleon Diamond Necklace," which provides the history and a gemological characterization of this historic necklace, given by Napoleon Bonaparte to Empress Marie Louise of France on the birth of their son in 1811. The high proportion of type IIa colorless to near-colorless diamonds with good clarity indicates that the standards for a fine diamond 200 years were similar to those used today.
The Lab Notes section presents recent discoveries from the GIA Laboratory, such as apatite inclusions in spessartine and a diamond with large etch channels filled with iron sulfides. Highlights from Gem News International include Namibian diamond mining by Namdeb, a new locality for copper-bearing Paraíba-type tourmaline from Nigeria, and a synthetic beryl that simulates Paraíba tourmaline.
To purchase a copy of the Winter issue or to subscribe to Gems & Gemology, contact the GIA G&G web site or contact Circulation Coordinator Debbie Ortiz by calling 001 (760) 603-4000, ext. 7142.
In the lead article, "Latest-Generation CVD-Grown Synthetic Diamonds from Apollo Diamond Inc.," Dr. Wuyi Wang and a team of researchers report on the properties of these new products. Now marketed in colorless, near-colorless, and fancy-color varieties, they show significant improvements in size, color, and clarity over the samples examined by GIA in 2003. The article describes the unusual internal graining and birefringence, complex fluorescence zoning, and spectroscopic features that characterize the material.
"With recent advances in CVD synthesis, Apollo's latest lab-created diamonds are comparable in color and clarity to natural diamonds in the marketplace," said G&G Editor-in-Chief Alice S. Keller. "This article by Dr. Wang and colleagues is an essential guide to consistent identification of CVD synthetic diamonds."
In "Yellow Mn-rich Tourmaline from the Canary Mining Area, Zambia," Brendan Laurs and coauthors explore the world's most important source of this vivid elbaite. They present a gemological characterization and geologic investigation of the "canary" tourmaline, which is notable for its high manganese and low iron content.
Next, Dr. Sally Eaton-Magaña, et al.'s "Fluorescence Spectra of Colored Diamonds Using a Rapid, Mobile Spectrometer" examines the application of fluorescence spectroscopy to help characterize fancy-color diamonds. In this study, the fluorescence spectra of the natural-color diamond samples tested generally corresponded to bodycolor. The article also illustrates the potential of the inexpensive, portable charge-coupled device (CCD) spectrometer for characterizing fluorescence and phosphorescence in diamond.
The Winter issue lineup also includes "An Examination of the Napoleon Diamond Necklace," which provides the history and a gemological characterization of this historic necklace, given by Napoleon Bonaparte to Empress Marie Louise of France on the birth of their son in 1811. The high proportion of type IIa colorless to near-colorless diamonds with good clarity indicates that the standards for a fine diamond 200 years were similar to those used today.
The Lab Notes section presents recent discoveries from the GIA Laboratory, such as apatite inclusions in spessartine and a diamond with large etch channels filled with iron sulfides. Highlights from Gem News International include Namibian diamond mining by Namdeb, a new locality for copper-bearing Paraíba-type tourmaline from Nigeria, and a synthetic beryl that simulates Paraíba tourmaline.
To purchase a copy of the Winter issue or to subscribe to Gems & Gemology, contact the GIA G&G web site or contact Circulation Coordinator Debbie Ortiz by calling 001 (760) 603-4000, ext. 7142.
20th February 2008