CARLSBAD, Calif., - Aug. 1, 2008 - The Summer 2008 issue of GIA’s Gems & Gemology (G&G) features a replica of the original Koh-i-Noor diamond, a study of emeralds from a historical Norwegian deposit and investigations of coated tanzanite and two topaz treatments.

Highlighting the issue is Scott Sucher and Dale Carriere’s “The Use of Laser and X-ray Scanning to Create a Model of the Historic Koh-i-Noor Diamond.” The original Koh-i-Noor, which was owned by a succession of rulers across Asia for hundreds of years before it became part of the crown jewels of England, was recut from 191.03 ct to 105.6 ct in 1852. The authors, using photographic and scanning methods applied to a plaster cast of the original stone, fashioned a cubic zirconia replica that recreated its surface topology and optical performance.

“The Koh-i-Noor is one of the world’s most famous diamonds, a legendary stone with a rich history,” said G&G Editor-in-Chief Alice Keller. “By using modern technology to create both a computer model and a CZ replica of the original diamond and analyze its cut, the authors have made an important contribution to the history of gemology.”

In “Characterization of Emeralds from a Historical Deposit: Byrud (Eidsvoll), Norway,” Dr. Benjamin Rondeau and a team of co-authors reveal the distinguishing gemological, spectroscopic and chemical characteristics of gems from this classic locality.

The Summer issue lineup also includes two brief articles. First, Shane McClure and Dr. Andy H. Shen of the GIA Laboratory describe a new coated tanzanite and the identification clues provided by microscopic examination and spectroscopic analysis. Then, Dr. Harald Gabasch and co-authors examine the coloring of topaz by two surface-treatment methods -- coating and diffusion -- that have become viable alternatives to irradiation.

The Lab Notes section presents recent discoveries from the GIA Laboratory, including gem-quality CVD synthetic diamonds with traces of boron, bleached Pinctada margaritifera cultured pearls in non-“chocolate” colors and a filled diamond with very subtle flash-effect colors. Highlights from Gem News International include new rubies and yellow danburite from Tanzania, “red andesine” from China, a new source of Persian turquoise and a variety of tourmaline imitations sold in Afghanistan.

To purchase the Summer 2008 issue or subscribe to G&G today, click here or contact Circulation Coordinator Debbie Ortiz by calling toll-free (800) 421-7250, ext. 7142. From outside the U.S. and Canada, dial (760) 603-4000, ext. 7142.

Gems & Gemology can also be found at GIA’s Web site on www.gia.edu.