Winter 2008 Gems & Gemology
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www.gia.edu/gemsandgemology ® EDITORIAL Editor-in-Chief Editor Editors, Lab Notes STAFF Alice S. Keller Brendan M. Laurs Thomas M. Moses [email protected] GIA, The Robert Mouawad Campus Shane F. McClure 5345 Armada Drive Managing Editor Carlsbad, CA 92008 Editor, Gem News International Thomas W. Overton (760) 603-4503 Brendan M. Laurs [email protected] [email protected] Technical Editor Editors, Book Reviews Associate Editor Emily V. Dubinsky Susan B. Johnson Stuart D. Overlin [email protected] Jana E. Miyahira-Smith [email protected] Thomas W. Overton Consulting Editor Circulation Coordinator Carol M. Stockton Mary Navarro Editors, Gemological Abstracts Contributing Editor (760) 603-4000, ext. 7142 Brendan M. Laurs James E. Shigley [email protected] Thomas W. Overton PRODUCTION Art Director Production Assistant G&G Online: STAFF Karen Myers Suzan Pearman gia.metapress.com EDITORIAL Shigeru Akamatsu Jaroslav Hyr`´sl Thomas M. Moses Tokyo, Japan Prague, Czech Republic New York, New York REVIEW BOARD Edward W. Boehm A. J. A. (Bram) Janse Mark Newton Solana Beach, California Perth, Australia Coventry, United Kingdom James E. Butler Alan Jobbins George Rossman Washington, DC Caterham, United Kingdom Pasadena, California Alan T. Collins Mary L. Johnson Kenneth Scarratt London, United Kingdom San Diego, California Bangkok, Thailand John Emmett Anthony R. Kampf James E. Shigley Brush Prairie, Washington Los Angeles, California Carlsbad, California Emmanuel Fritsch Robert E. Kane Christopher P. Smith Nantes, France Helena, Montana New York, New York Henry A. Hänni Lore Kiefert Christopher M. Welbourn Basel, Switzerland New York, New York Reading, United Kingdom Online subscriptions, and print subscriptions sent to addresses in the U.S., are priced as follows: $74.95 for one year (4 issues), SUBSCRIPTIONS $194.95 for three years (12 issues). Print subscriptions sent elsewhere are $85.00 for one year, $225.00 for three years. Combination print/online subscriptions are $99.95 in the U.S. and $110.00 elsewhere for one year, and $269.95 in the U.S. and $300.00 elsewhere for three years. Canadian subscribers should add GST. Discounts of $10 (one year) and $15 (three years) are available for renewals, GIA alumni, and current GIA students. Please have your student or alumni number ready when ordering. Electronic (PDF) versions of all articles and sections from Spring 1981 forward can be purchased at gia.metapress.com for $10 each. Full issue access can be purchased for $20. To purchase subscriptions and print back issues, visit www.gia.edu/gemsandgemology or contact the Circulation Coordinator. To obtain a Japanese translation of Gems & Gemology, contact GIA Japan, Okachimachi Cy Bldg., 5-15-14 Ueno, Taitoku, Tokyo 110, Japan. Our Canadian goods and service registration number is 126142892RT. ATABASE Gems & Gemology’s impact factor is 1.227 (ranking 11th out of the 26 journals in the Mineralogy category), according to D Thomson Scientific’s 2007 Journal Citation Reports (issued July 2008). Gems & Gemology is abstracted in Thompson Scientific COVERAGE products (Current Contents: Physical, Chemical & Earth Sciences and Science Citation Index—Expanded, including the Web of Knowledge) and other databases. For a complete list, see www.gia.edu/gemsandgemology. MANUSCRIPT Gems & Gemology welcomes the submission of articles on all aspects of the field. Please see the Guidelines for Authors on our Website, or contact the Managing Editor. Letters on articles published in Gems & Gemology are also welcome. SUBMISSIONS Abstracting is permitted with credit to the source. Libraries are permitted to photocopy beyond the limits of U.S. copyright law for private use of patrons. Instructors are permitted to photocopy isolated articles for noncommercial classroom use without fee. COPYRIGHT Copying of the photographs by any means other than traditional photocopying techniques (Xerox, etc.) is prohibited without the AND REPRINT express permission of the photographer (where listed) or author of the article in which the photo appears (where no photographer PERMISSIONS is listed). For other copying, reprint, or republication permission, please contact the Managing Editor. Gems & Gemology is published quarterly by the Gemological Institute of America, a nonprofit educational organization for the gem and jewelry industry, The Robert Mouawad Campus, 5345 Armada Drive, Carlsbad, CA 92008. Postmaster: Return undeliverable copies of Gems & Gemology to GIA, The Robert Mouawad Campus, 5345 Armada Drive, Carlsbad, CA 92008. Any opinions expressed in signed articles are understood to be the opinions of the authors and not of the publisher. ABOUT The GIA D-to-Z color grading system revolutionized the manufacture of diamond jewelry because it allowed for tighter control THE COVER over the quality of the diamonds used in individual pieces. At the same time, an important market developed for the finest, D-color, diamonds, as represented by the rings shown here. The D color, VVS2 round brilliant in the ring on the right weighs 7.12 ct; courtesy of Harry Winston Inc. The D color, VVS2 heart-shaped diamond in the other ring weighs 10 ct; from Mona Lee Nesseth, Custom Estate Jewels (courtesy of a private collector). The diamonds in the pin have colors ranging from F to I, and their total weight is 21.10 carats; courtesy of Louis Glick & Co. The necklace is a diamond sautoir by Van Cleef & Arpels, Paris, circa 1925; courtesy of a private collector. Photo © GIA and Harold & Erica Van Pelt. Color separations for Gems & Gemology are by Pacific Plus, Carlsbad, California. Printing is by Allen Press, Lawrence, Kansas. © 2008 Gemological Institute of America All rights reserved. ISSN 0016-626X ® Winter 2008 VOLUME 44, NO. 4 EDITORIAL _____________ 295 Challenges, Changes, and New Directions Alice S. Keller FEATURE ARTICLES _____________ 296 Color Grading “D-to-Z” Diamonds at the GIA Laboratory Carat Points John M. King, Ron H. Geurts, Al M. Gilbertson, and James E. Shigley Examines the history and current methology of the GIA Laboratory’s system for color grading colorless to light yellow polished diamonds, which is a critical component in the valuation of these gems. 322 Rubies and Sapphires from Winza, Central Tanzania Dietmar Schwarz, Vincent Pardieu, John M. Saul, Karl Schmetzer, Brendan M. Laurs, pg. 310 Gaston Giuliani, Leo Klemm, Anna-Kathrin Malsy, Eric Erel, Christoph Hauzenberger, Garry Du Toit, Anthony E. Fallick, and Daniel Ohnenstetter Describes the mining and geology of this new source of untreated rubies, and characterizes the gem corundum produced there, which arrived on the market in early 2008. 348 The Wittelsbach Blue Rudolf Dröschel, Jürgen Evers, and Hans Ottomeyer Reviews the colorful past of this 35.56 ct gem, the former crown jewel of Bavaria and one of the largest historic blue diamonds ever fashioned, and presents the pg. 323 results of known gemological investigations. REGULAR FEATURES _____________________ 364 Lab Notes Fancy dark brown-yellow zoned type IIa/IIb diamond • HPHT-treated CVD synthetic diamond submitted for Dossier grading • Quartz with secondary covellite dendrites • Induced copper contamination of tourmaline pg. 353 369 Gem News International Andesine from Tibet and Inner Mongolia • Vivid kunzite from Pala, California • Natural pearls of the Veneridae family • Synthetic citrine with abundant nail- head spicules • “Neptunian” beads from Asia • Purplish blue synthetic quartz • Dyed chalcedony resembling chrysocolla S1 Book Reviews S4 Gemological Abstracts S12 Annual Index pg. 366 The current global economic downturn your computer monitor will be the same as that verified has affected every industry, and ours is no exception. As by art director Karen Myers while the journal is on press. one consequence, GIA has decided to postpone the second However, the online version uses the same electronic files Gemological Research Conference, originally scheduled that are used for the printed version. for August 21–23, 2009. Our foremost concern is that G&G Online is hosted by MetaPress, a division of the many people who had hoped to participate are now facing world’s largest subscription agency, EBSCO, at gia.meta- significant budget and travel restrictions, so—rather than press.com. There you will find electronic versions of every risk the success of this important event—the conference article and journal section from 1981 through the present. will wait until the economy improves. Our heartfelt Editorials, Letters, Book Reviews, and Gemological thanks go to everyone who was involved with the 2009 Abstracts (as well as all the articles on our Free Downloads GRC, and we look forward to the time when preparations page) are available without charge. For a limited time, we are can be resumed. also offering a free look at the entire Fall 2008 issue online. To better continue delivering comprehensive research Other articles and sections can be purchased for just $10 and exceptional gem photography, Gems & Gemology each, and entire issues for $20 each. (The smaller-format, will be shifting a portion of its content online, starting predominately black-and-white issues from 1934 to 1980 can with this issue. The Book Reviews and Gemological still be downloaded from the G&G web site at no cost.) If Abstracts sections are now available (in their entirety) only you’re interested in upgrading your subscription to include in electronic form, as are our year-end subject and author online access, please contact our circulation coordinator. indexes, traditionally part of the Winter issue. The annual Gems & Gemology is no stranger to challenges and indexes will also be combined with our online cumulative change. When Robert Shipley published the first issue in index, which covers the years 1981–2008. Additional con- 1934, the world was in the throes of the Great Depression. tent, such as supplemental tables, spectra, and images, When the current large-format version was launched in will be featured online in the G&G Data Depository. To 1981, the diamond industry was still recovering from the use these resources, all of them available free of charge, speculative boom and bust of the late 1970s.