Fall Issue of Gems & Gemology Examines "Green Amber," Tavernier Blue Diamond

CARLSBAD, Calif.– Oct. 20, 2009 – The Fall 2009 issue of Gems & Gemology (G&G), released Oct. 5, looks closely at a treated gem material being marketed as “green amber,” as well as a new gemological test to detect HPHT treatment in type I diamonds.

The publication also offers a crystallographic analysis of the Tavernier Blue diamond, an update on Ammolite mining in Canada, and more.

The lead article, “Characterization of ‘Green Amber’ with Infrared and Nuclear Magnetic Resonance Spectroscopy,” by Dr. Ahmadjan Abduriyim and co-authors, provides an in-depth look at this relatively new material, which is created by treating amber or its much younger counterpart, copal, under heat and pressure. The process artificially “ages” copal and imparts a green to yellow-green color in some samples. The treatment can be detected by characteristic spectral features, but it is not always possible to establish whether the starting material was amber or copal.

“A new treated gem such as ‘green amber’ poses an immediate challenge to the industry for proper identification,” said G&G Editor-in-Chief Alice Keller. “This article greatly enhances our understanding of this attractive product.”

The next article, “A Crystallographic Analysis of the Tavernier Blue Diamond” by Scott D. Sucher, builds on recent research to portray a more accurate model of this historic diamond, a predecessor to the Hope. In “‘Fluorescence Cage’: Visual Identification of HPHT-Treated Type I Diamonds,” Drs. Inga A. Dobrinets and Alexander M. Zaitsev review their discovery of a luminous network of fluorescence at the facet edges and junctions of these treated diamonds. Visible with a fluorescence microscope, this network feature can provide a quick screening method for some HPHT treatment.

Other articles cover ammolite production in Southern Alberta, Canada; polymer-filled aquamarine; the discovery of gem-quality yellow-green haüyne from Tanzania; and aquamarine from northern Italy.

The Lab Notes section features the latest discoveries from the GIA Laboratory, including a treated Fancy red diamond, a useful technique to identify negative crystals in ruby, and a diamond with patterned green radiation stains. Gem News International includes demantoid samples from a new locality at Ambanja, Madagascar, and new rubies from Mozambique, among many other topics.

PDF versions of the Fall 2009 issue are available at http://gia.metapress.com. To purchase a print copy or to subscribe to G&G, visit www.gia.edu/_webapps/gg/orderform/, or email martha.rivera@gia.edu. Call toll-free (800) 421-7250, ext. 7142. From outside the U.S. and Canada, call (760) 603-4000, ext. 7142.