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Summer 1987 Gems & Gemology

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Summer 1987 Gems & Gemology VOLUME XXIII SUMMER 1987 rn The quarterly journal of the Gemological Institute of America SUMMER 1987 Volume 23 Number 2 TABLE OF CONTENTS FEATURE 63 Gemstone Durability: Design to Display ARTICLES Deborah Dupont Martin 78 The Occurrence and Gemological Properties of Wessels Mine Sugilite James E. Shigley, John 1. Koivulti, and C. W Fryer NOTES, , 90 Three Notable Fancy-Color Diamonds: Purplish AND NEW Red, Purple-Pink, and Reddish Purple TECHNIQUES Robert E. Kane 96 The Separation of Natural from Synthetic Emeralds by Infrared Spectroscopy Carol M.Stockton 100 The Rutilated Topaz Misnomer John I. Koivula REGULAR 104 Gem Trade Lab Notes FEATURES Ill Editorial Forum 113 Book Reviews 115 Gemological Abstracts 122 Gem News ABOUT THE COVER: A wide variety of gemstones are now available for use in jewelry. While some of the more unusual stones lend themselves to fascinating designs, as evidenced by the 396.3-ct Iiunzite shown here, they also require special considerations. The article by Deborah Dupont Martin in this issue examines gemstone durability as it affects the handling of gems in various jewelry design, manufacturing, and care procedures. Included is a chart covering dura- bility variables for 31 sein species, The kunzite pendant, set in 18K gold wit11 6.33 ct of dia- mods, is courtesy of Tiffany es) Co., New York and Los Angeles. Photo @ Harold es) Ericu Van Pelt -Photographers, Los Angeles, CA. Typesetting for Gems & Gemology is by Scientific Con~position,Los Angeles, CA. Color separa- tions me. by Effective Graphics, Compton, CA. Printing is by Waverly Press. Easton, IWD. @ 1987 Gemological Institute of America All rights reserved ISSN 001 6-626X EDITORIAL Editor-in-Chicf Editor Editor, Gem Trade Lab Notes STAFF Richard T Liddicoat, Jr. Alice S. Keller C. W. Fryer Associate Editors 1660 Stewart St. Editor, Gemological Abstracts Peter C. Keller Santa Monica, CA 90404 Dona M. Dirlam Telephone: (213) 829-2991 D. Vincent Manson Editor, Book Reviews John Sinkankas Editorial Assistant Elise B. Misiorowski Nancy K. Hays Technical Editor Contributing Editor and Carol M. Stockton Subscriptions Editor, Gem News Lisa Hebenstreit, Manager John I. Koivula Diane J. Emmons, Assistant Managcr PRODUCTION Jennifer Erosions Julie Matz Cecile Miranda STAFF Linda Manion Patricia Mayer Ruth Patchick Susan Kingsbury Peter Johnston EDITORIAL William E. Boyajian Robert C. Kammerling Sallie Morton REVIEW BOARD Santa Monica, CA Santa Monica, CA San lose, CA Robert Crovvningshield Anthony R. Kampf Kurt Nassau New York, NY Los Angeles, CA Bernardsville, NJ Dennis Foltz Robert E. Kane Ray Page Santa Monica, CA Los Angeles, CA Santa Monica, CA Chuck Fryer John 1. Koivula George Rossman Santa Monica, CA Santa Monica. CA Pasadena, CA C. S. Hiirlbut, Jr. Hcnry 0. A. Mcyer James E. Shigley Cam bridge, MA West Lafayette, IN Santa Monica, CA SUBSCRIPTIONS Subscriptions in the U.S.A. aie priced as follows: $32.95 for one year (4 issues), $89.95 for three years (12 issues). Subscriptions sent elsewhere arc $42.00 for one year, $120.00 for three years. Special annual subscription rates arc available for all students activcly involved in a GIA program: $29.95 U.S.A., $39.00 elsewhere. Your student number must be listed at the time your subscription is entered. Single issues may be purchased for $8.50 in the U.S.A., S11.50 clscwherc. Discounts are given for bulk orders of 10 or more of any one issue. A limited number of back issues of G&G are also available for purchase. Please address all inquiries regarding subscriptions and the purchase of single copies or back issues to the Subscription Manager. For subscriptions and back issues in Italy, please contact Institute Gemn~ologicoMediterraneo, Via Marn~olaia#14, -38033, Cavalese TN, Italy. MANUSCRIPT Gems ed Gemology wclcomes the submission of articles on all aspects of the field. Please see the Suggestions for SUBMISSIONS Authors in the Summer 1986 issue of the journal, or contact the editor for a copy. Letters on articles published in Gems e) Gemology and other relevant matters are also wclcome. COPYRIGHT Abstracting is permitted with credit to the source. Libraries are permitted to photocopy beyond the limits of U.S. AND REPRINT copyright law for private use of patrons. Instructors are permitted to photocopy isolated articles for noncommercial PERMISSIONS classroon~use without fee. For other copying, reprint, or republication permission, please contact the Editor. Gems a) Geinology is published quarterly by the Gemological Institute of America, a nonprofit educational organization for the jewelry industry, 1660 Stewart St., Santa Monica, CA 90404. Postmaster: Return undelivcrablc copies of Gems 6) Gemology to 1660 Stewart St., Santa Monica, CA 90404. Any opinions expressed in signed articles arc understood to be the views of the authors and not of the publishers. GEMSTONE DURABILITY: DESIGN TO DISPLAY By Deborah Dupont Martin Knowledge of the durability of a gem- n today's market, most jewelers no longer deal solely stone is critical to understanding the I with traditional gems such as diamonds, rubies, sap- risks involved in the various setting, re- phires, and pearls. The increasing availability and popu- pair, and cleaning procedures commonly larity of a wide range of colored stones-tanzanite, used by the jeweler. Some gemstones need tsavorite, iolite, and tourmaline (figure l), to name a few - attention in display because of their reac- has opened a host of new possibilities in jewelry, but it has tion to heat and/or light. This article re- views gemstone durability considerations also added a n~ultitude'ofnew risks. for 31 species and their varieties as they While many in the trade are qualified to deal effec- affect design decisions as well as repair, tively with most of these stones, virtually everyone cleaning, and display of the piece. I11 all associated with the design, manufacture, and sale of cases, tlie'reader is advised to consult an jewelry should be aware of the potential problems of a experienced bench jeweler before attempt- particular gem material. The designer must lznow which ing any potentially damaging procedures. mounting will protect the stone best while still enhancing The recon~ii~endatioiisin this article are its natural beauty. The bench jeweler is responsible for offered from a gemological viewpoint and determining what stones are at risk in which setting or as g~~idelinesonly. repair procedures. The salesperson, who has the greatest customer contact, must not only be aware of these design and bench considerations, but must also lznow the rules involved in various cleaning procedures and be able to ABOUT THE AUTHOR advise the customer regarding precautions in care and Ms. Marlin is an instructor in the Colored Stones wear. Some stones even require special display considera- Department 01 the Resident Gemology Program at tions because they are sensitive to light or to the heat that the Gemological Institute 01 America, Santa Monica, California. Prior to joining GIA, she can be produced in a case. worked as a bench jeweler for 10 years. The most important factor in designing, setting, re- Acknowledgments. The following people were ex- pairing, or cleaning a piece of jewelry is durability. Essen- tremely helpful in reviewing the manuscript and tially, durability is the gemstone's ability to resist scratch- providing informat~on:Thornton Mann, Chuck At- ing (hardness),breaking (toughness),and effects caused by more, Dino DeGhionno, and Archie Curtis. Robert Kane was especially helpful in providing informa- heat, light, or chemicals (stability). The present article tion tor the chart and photographs. Thanks to examines gemstone durability and discusses the limita- Chris Keenan lor supplying photographs. Special tions and advantages of different settings, repair and thanks to Steven C. Martin lor providing many in- sights and useful information, as well as encour- cleaning procedures, and display practices for many differ- agement. The following graciously supplied jewel- ent stones. A chart is included to provide guidelines ry for photographs: The Altobelli Jewelers, The relating to durability and how it affects these procedures Gold Masters, Silverhorn, Steven C. Martin, and C. Y Sheng. Ruth Patcliick did a wonderful job for 31 gem species and their varieties. typing the manuscript. It is important to note that the following information V> 1987 Gemolog~calInstitute of America pertains to natural gems only, including common enhan- Durability of Gemstones GEMS & GEMOLOGY Summer 1987 63 cements, but not to any man-made materials. The most types of setting, cleaning, and repair pro- identity of a gem must be established before any cedures (e.g., diamond and corundum) may be used procedure beyond cleaning with warm soapy water in a wide variety of jewelry designs. For stones of may be attempted. If you cannot determine with lesser durability, however, possible weaknesses certainty whether or not a stone has been en- must be considered in the selection of a setting hanced, assume that it has and take the more style (see chart). A gem with poor toughness, such conservative approach. Many qualified bench jew- as topaz, would not be a candidate for a channel or elers will be able to perform procedures that are flush style setting; chances are the stone would not recommended here, but such an individual is break. Heat-sensitive stones such as emerald, not always available. This article, therefore, is tsavorite, and tanzanite could be subject to dam- intended to serve as guidelines (and guidelines age if set in a style that requires soldering near only) in these areas. Since there is some risk stones already in place. involved with any stone, consultation with a Some inclusions can increase the chance of qualified bench jeweler is always recommended. breakage during setting. Because such inclusions The information in this article was compiled vary from stone to stone, it is wise to examine the based on Webster (1983),Sinlzanlzas (1972))Palache stone under magnification before setting it.
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