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FALL 2015 VOLUME LI THE UARTERLY JOURNAL OF THE GEMOLOGICAL INSTITUTE OF AMERICA Colombian Trapiche Emeralds Large Colorless HPHT-Grown Synthetic Diamonds Diamonds from the Letšeng Mine Fall 2015 VOLUME 51, No. 3 EDITORIAL 221 Trapiche and More... Duncan Pay FEATURE ARTICLES 222 Colombian Trapiche Emeralds: Recent Advances in Understanding Their Formation Isabella Pignatelli, Gaston Giuliani, Daniel Ohnenstetter, Giovanna Agrosì, pg. 254 Sandrine Mathieu, Christophe Morlot, and Yannick Branquet Proposes a model for trapiche emerald formation based on petrographic, spectroscopic, and chemical examination. 260 Large Colorless HPHT-Grown Synthetic Gem Diamonds from New Diamond Technology, Russia Ulrika F.S. D’Haenens-Johansson, Andrey Katrusha, Kyaw Soe Moe, Paul Johnson, and Wuyi Wang pg. 270 Examines a new source of colorless and near-colorless gem-quality HPHT synthetic diamonds using spectroscopic and gemological analysis. 280 Letšeng’s Unique Diamond Proposition Russell Shor, Robert Weldon, A.J.A. (Bram) Janse, Christopher M. Breeding, and Steven B. Shirey Explores the history, geology, and current production of this unique source of large diamonds. NOTES AND NEW TECHNIQUES 300 Origin Determination of Dolomite-Related White Nephrite through Iterative-Binary Linear Discriminant Analysis Zemin Luo, Mingxing Yang, and Andy H Shen A technique for origin identification based on statistical analysis and LA-ICP-MS spectrometry. pg. 293 REGULAR FEATURES 312 Lab Notes Unusual graining structure in pink diamond • Yellow HPHT-treated rough diamond • Color- zoned emerald • Orange faceted eosphorite • Large faceted hibonite • Dyed and natural green jadeite • Coated kornerupine beads • Assembled cultured blister pearl with unusual pg. 325 feature • Three large natural abalone pearls • Irradiated green-blue CVD synthetic diamonds • Polished freeform topaz imitating diamond rough 323 2015 G&G Challenge Winners 324 G&G Micro-World Cleavage system in pink diamond • Rough diamond fragment with green cleavage surface • Blue gahnite inclusions in cat’s-eye heliodor • Trapiche pezzottaite • Modified Rheinberg illumination • Glassy melt inclusions in Montana sapphires • Molybdenite in topaz 331 Letters 334 Gem News International Large star emerald • Natural faceted red rutile • Rare “star and cross” quartz from Brazil • Serpentine cabochon with olive-green color • Characterization of Thai-Myanmar petri- fied woods • Coated rock crystal imitation of ruby • Color-change cubic zirconia as peridot imitation • Coral inclusions in plastic • Hydrogrossular garnet imitating jadeite • Impregnated and dyed turquoise • Errata • Tino Hammid (1952–2015) Editorial Staff Editor-in-Chief Editors, Lab Notes Contributing Editors Duncan Pay Thomas M. Moses James E. Shigley gia.edu/gems-gemology [email protected] Shane F. McClure Andy Lucas Donna Beaton Subscriptions Managing Editor Editors, Micro-World Copies of the current issue may be purchased for Stuart D. Overlin Nathan Renfro Editor-in-Chief Emeritus $29.95 plus shipping. Subscriptions are $79.99 for one [email protected] Elise A. Skalwold Alice S. Keller year (4 issues) in the U.S. and $99.99 elsewhere. Cana- John I. Koivula dian subscribers should add GST. Discounts are avail- Editor Customer Service able for group subscriptions, GIA alumni, and current Jennifer-Lynn Archuleta Editors, Gem News Martha Erickson GIA students. To purchase print subscriptions, visit [email protected] Emmanuel Fritsch (760) 603-4502 store.gia.edu or contact Customer Service. For insti- tutional rates, contact Customer Service. Gagan Choudhary [email protected] Technical Editors Christopher M. Breeding Tao Z. Hsu Database Coverage Gems & Gemology’s impact factor is 0.778, accord- [email protected] Editorial Assistants ing to the 2013 Thomson Reuters Journal Citation Jennifer Stone-Sundberg Brooke Goedert Reports (issued July 2014). G&G is abstracted in Erin Hogarth Thomson Reuters products (Current Contents: Phys- ical, Chemical & Earth Sciences and Science Cita- tion Index—Expanded, including the Web of Production Staff Knowledge) and other databases. For a complete list Creative Director Photographer Production Supervisor of sources abstracting G&G, go to gia.edu/gems- gemology, and click on “Publication Information.” Faizah Bhatti Robert Weldon Richard Canedo Image Specialists Video Production Production Specialist Manuscript Submissions Gems & Gemology, a peer-reviewed journal, welcomes Kevin Schumacher Larry Lavitt Juan Zanahuria the submission of articles on all aspects of the field. Eric Welch Pedro Padua Please see the Author Guidelines at gia.edu/gems- Multimedia Specialist Nancy Powers gemology or contact the Managing Editor. Letters on Illustrator Betsy Winans Lynn Nguyen articles published in G&G are also welcome. Please Peter Johnston note that Field Reports, Lab Notes, Gem News Inter- national, and Micro-World entries are not peer-reviewed sections but do undergo technical and editorial review. Editorial Review Board Copyright and Reprint Permission Ahmadjan Abduriyim A.J.A. (Bram) Janse Benjamin Rondeau Abstracting is permitted with credit to the source. Li- braries are permitted to photocopy beyond the limits Tokyo, Japan Perth, Australia Nantes, France of U.S. copyright law for private use of patrons. In- Timothy Adams E. Alan Jobbins George R. Rossman structors are permitted to reproduce isolated articles San Diego, California Caterham, UK Pasadena, California and photographs/images owned by G&G for noncom- mercial classroom use without fee. Use of photo- Edward W. Boehm Mary L. Johnson Kenneth Scarratt graphs/images under copyright by external parties is Chattanooga, Tennessee San Diego, California Bangkok, Thailand prohibited without the express permission of the pho- James E. Butler Anthony R. Kampf Andy Shen tographer or owner of the image, as listed in the cred- Washington, DC Los Angeles, California Wuhan, China its. For other copying, reprint, or republication permission, please contact the Managing Editor. Alan T. Collins Robert E. Kane Guanghai Shi Gems & Gemology is published quarterly by the London, UK Helena, Montana Beijing, China Gemological Institute of America, a nonprofit educa- John L. Emmett Stefanos Karampelas James E. Shigley tional organization for the gem and jewelry industry. Brush Prairie, Washington Lucerne, Switzerland Carlsbad, California Postmaster: Return undeliverable copies of Gems & Emmanuel Fritsch Lore Kiefert Elisabeth Strack Gemology to GIA, The Robert Mouawad Campus, Nantes, France Lucerne, Switzerland Hamburg, Germany 5345 Armada Drive, Carlsbad, CA 92008. Our Canadian goods and service registration number Eloïse Gaillou Ren Lu Wuyi Wang is 126142892RT. Paris, France Wuhan, China New York, New York Any opinions expressed in signed articles are under- Gaston Giuliani Thomas M. Moses Christopher M. Welbourn stood to be opinions of the authors and not of the Nancy, France New York, New York Reading, UK publisher. Jaroslav Hyršl Nathan Renfro Prague, Czech Republic Carlsbad, California About the Cover The lead article in this issue is an in-depth study on the geological formation and growth of Colombian trapiche emeralds. The cover photo shows a 58.83 ct crystal specimen (left) and a 22.74 ct cabochon (right), both displaying the material’s signature six-rayed pattern, from the renowned Peñas Blancas emerald region. The host rock, seen in the background, is carbonaceous shale containing veins of calcite, pyrite, and minute crystals of low-grade emer- ald. Photo by Robert Weldon/GIA, courtesy of Jose Guillermo Ortiz and Colombian Emeralds Co. Printing is by L+L Printers, Carlsbad, CA. GIA World Headquarters The Robert Mouawad Campus 5345 Armada Drive Carlsbad, CA 92008 USA © 2015 Gemological Institute of America All rights reserved. ISSN 0016-626X Trapiche and More... Colombia’s unique trapiche emeralds exert a fascination for many gemologists. In fine specimens, the combination of rich, gemmy green color with the six spokes’ geometry is visually arresting. In our lead article, we’re delighted to present a comprehensive paper on these intriguing gems by a team of researchers headed by Isabella Pignatelli and Gaston Giuliani. They review the geology of trapiche emerald, provide 3-D petrographic examination of their crystals along with spectroscopic and chemical analyses, and propose a new formation model informed by their recent work. We hope this paper will serve as the primary refer- ence on these one-of-a-kind gems for many years to come. Take a look at our cover photo and decide whether trapiche is a gemological curiosity or an object of beauty in its own right. In our next paper, GIA’s Ulrika D’Haenens-Johansson and her coauthors investigate the gemological properties of colorless to near-colorless HPHT-grown synthetic diamonds produced specifically for gem use by a Russian firm, New Diamond Technology. Their analysis of 44 faceted samples ranging up to 5.11 ct provides convincing evidence of the quality improvements—and increased size—of synthetics grown by this method. Meanwhile, Lesotho’s Letšeng-la-Terae mine is currently enjoying a renaissance. Rising prices for large, high- quality diamonds have overcome the twin challenges of this unique mine’s remote location and low ore grade. In our third article, GIA’s Russell Shor and Robert Weldon and their co-authors profile Letšeng A gemological curiosity or an object of to explain how the current owners have adapted their beauty in its own right? operations to promote recovery of the mine’s biggest gems and increase profitability.
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  • Bulletin 65, the Minerals of Franklin and Sterling Hill, New Jersey, 1962

    Bulletin 65, the Minerals of Franklin and Sterling Hill, New Jersey, 1962

    THEMINERALSOF FRANKLINAND STERLINGHILL NEWJERSEY BULLETIN 65 NEW JERSEYGEOLOGICALSURVEY DEPARTMENTOF CONSERVATIONAND ECONOMICDEVELOPMENT NEW JERSEY GEOLOGICAL SURVEY BULLETIN 65 THE MINERALS OF FRANKLIN AND STERLING HILL, NEW JERSEY bY ALBERT S. WILKERSON Professor of Geology Rutgers, The State University of New Jersey STATE OF NEw JERSEY Department of Conservation and Economic Development H. MAT ADAMS, Commissioner Division of Resource Development KE_rr_ H. CR_V_LINCDirector, Bureau of Geology and Topography KEMBLEWIDX_, State Geologist TRENTON, NEW JERSEY --1962-- NEW JERSEY GEOLOGICAL SURVEY NEW JERSEY GEOLOGICAL SURVEY CONTENTS PAGE Introduction ......................................... 5 History of Area ................................... 7 General Geology ................................... 9 Origin of the Ore Deposits .......................... 10 The Rowe Collection ................................ 11 List of 42 Mineral Species and Varieties First Found at Franklin or Sterling Hill .......................... 13 Other Mineral Species and Varieties at Franklin or Sterling Hill ............................................ 14 Tabular Summary of Mineral Discoveries ................. 17 The Luminescent Minerals ............................ 22 Corrections to Franklln-Sterling Hill Mineral List of Dis- credited Species, Incorrect Names, Usages, Spelling and Identification .................................... 23 Description of Minerals: Bementite ......................................... 25 Cahnite ..........................................