GemmologyThe Journal of 2015 / Volume 34 / No. 6 The Gemmological Association of Great Britain Gem-A Conference 21–22 November 2015 The Gem-A Conference will be held on 21–22 November 2015, at the Royal Institute of British Architects (RIBA) in Marylebone, London. Incorporating the 18th Symposium of the Federation of European Education in Gemmology (FEEG), this year’s Conference promises to be bigger and better than ever, with a host of exciting speakers, events and workshops scheduled over the weekend. Visit www.gem-a.com or email [email protected] to book your place. Join us. The Gemmological Association of Great Britain, 21 Ely Place, London, EC1N 6TD, UK. T: +44 (0) 20 7404 3334 F: +44 (0) 20 7404 8843. Registered charity no. 1109555. A company limited by guarantee and registered in England No. 1945780. Registered Office: 3rd Floor, 1-4 Argyll Street, London W1F 7LD. Conference_A4_06-2015.indd 1 23/06/2015 18:04:45 Contents GemmologyThe Journal of 2015 / Volume 34 / No. 6 COLUMNS p. 476 467 What’s New Automated melee screening p. 532 device|DFI Mid-UV Laser+ diamond screening system|DiaCam360| GemmoSphere|News on cobalt diffusion treatment of spinel, diamond-diamond doublet, temporary diamond colour treatment and low- temperature heat treatment of Mozambique ruby|ICGL ARTICLES Newsletter|Microcrystalline silica online lectures|What’s Feature Articles New in the Mineral World? 490 Green-Luminescing Hyalite Opal from Zacatecas, 470 Practical Gemmology Mexico A matched pair of opals, with By Emmanuel Fritsch, Peter K. M. Megaw, Tyler L. Spano, a catch Boris Chauviré, Benjamin Rondeau, Michael Gray, Thomas 472 Gem Notes Hainschwang and Nathan Renfro Chrysocolla chalcedony from Spain|Rhodochrosite from 510 Raman Spectroscopy of Ancient Beads from Devín Brazil|Tourmaline mining Castle near Bratislava and of Four Intaglios from in the DRC|Colour-zoned other Archaeological Finds in Slovakia Cr- and V-bearing tourmaline By Magdaléna Kadlečíková, Juraj Breza, Ľubomír Vančo, from Kenya|Heart of Pearls Miloš Gregor and Igor Bazovský tagging system|Modern doublets|Fracture-filled synthetic emerald, with synthetic quartz Gemmological Briefs inclusions|Glass imitations 518 The First Undisclosed Colourless CVD Synthetic of Cu-bearing Mozambique tourmaline|Quartz imitation Diamond Discovered in a Parcel of Natural of star sapphire|Chromium- Melee-Sized Diamonds diffused corundum|Lead-glass- By Thomas Hainschwang and Franck Notari filled yellow sapphires 524 The ‘Coffee-and-Cream’ Effect in Chatoyant Cabochons By Harold Killingback 532 Conferences The Journal of Cover Photo: Gemmology The colour appearance of Sinkankas Opal Symposium|AGA Las Vegas|Mallorca GemQuest| 2015 / Volume 34 / No. 6 The Journal of Gemmology this rough and cut hyalite Scottish Gemmological Association|Swiss Gemmological Society — 2015 / Volume 34 / No. 6 pp. 467– / Volume — 2015 opal from Zacatecas, Mexico, is due to its 540 XXX green daylight-induced Gem-A Notices fluorescence. The cut gems weigh 1.34–5.67 ct and were faceted by Michael 547 Learning Opportunities Gray; the specimen and 5.67 ct stone are courtesy 551 of Kristalle, Laguna Beach, New Media California, USA. Photo by The Gemmological Association of Great Britain Orasa Weldon. 555 Literature of Interest The Journal is published by Gem-A in collaboration with SSEF and with the support of AGL and GIT. ISSN: 1355-4565, http://dx.doi.org/10.15506/JoG.2015.34.6 i The Journal of emmology G THE GEMMOLOGICAL ASSOCIATION OF GREAT BRITAIN Editor-in-Chief Production Editor Marketing Consultant Brendan M. Laurs Mary A. Burland Ya’akov Almor [email protected] [email protected] [email protected] 21 Ely Place London EC1N 6TD Executive Editor Editor Emeritus Assistant Editor UK James H. Riley Roger R. Harding Michael J. O’Donoghue t: +44 (0)20 7404 3334 Associate Editors f: +44 (0)20 7404 8843 Edward Boehm, RareSource, Chattanooga, Tennessee, USA; Alan T. Collins, King’s College e: [email protected] London; John L. Emmett, Crystal Chemistry, Brush Prairie, Washington, USA; Emmanuel w: www.gem-a.com Fritsch, University of Nantes, France; Rui Galopim de Carvalho, Portugal Gemas, Lisbon, Registered Charity No. 1109555 Portugal; Lee A. Groat, University of British Columbia, Vancouver, Canada; Thomas Registered office: Palladium House, Hainschwang, GGTL Laboratories, Balzers, Liechtenstein; Henry A. Hänni, GemExpert, 1–4 Argyll Street, London W1F 7LD Basel, Switzerland; Jeff W. Harris, University of Glasgow; Alan D. Hart, The Natural History Museum, London; Ulrich Henn, German Gemmological Association, Idar- Oberstein; Jaroslav Hyršl, Prague, Czech Republic; Brian Jackson, National Museums Scotland, Edinburgh; Stefanos Karampelas, Gübelin Gem Lab Ltd., Lucerne, Switzerland; Lore Kiefert, Gübelin Gem Lab Ltd., Lucerne, Switzerland; Hiroshi Kitawaki, Central Gem Laboratory, Tokyo, Japan; Michael S. Krzemnicki, Swiss Gemmological Institute SSEF, President Basel; Shane F. McClure, Gemological Institute of America, Carlsbad, California; Jack Harry Levy M. Ogden, Striptwist Ltd., London; Federico Pezzotta, Natural History Museum of Milan, Vice Presidents Italy; Jeffrey E. Post, Smithsonian Institution, Washington DC, USA; Andrew H. Rankin, David J. Callaghan, Alan T. Collins, Kingston University, Surrey; George R. Rossman, California Institute of Technology, Noel W. Deeks, E. Alan Jobbins, Pasadena, USA; Karl Schmetzer, Petershausen, Germany; Dietmar Schwarz, AIGS Lab Co. Michael J. O’Donoghue, Ltd., Bangkok, Thailand; Menahem Sevdermish, GemeWizard Ltd., Ramat Gan, Israel; Andrew H. Rankin Guanghai Shi, China University of Geosciences, Beijing; James E. Shigley, Gemological Institute of America, Carlsbad, California; Christopher P. Smith, American Gemological Honorary Fellows Laboratories Inc., New York; Evelyne Stern, London; Elisabeth Strack, Gemmologisches Gaetano Cavalieri, Terrence S. Institut, Hamburg, Germany; Tay Thye Sun, Far East Gemological Laboratory, Singapore; Coldham, Emmanuel Fritsch Pornsawat Wathanakul, Gem and Jewelry Institute of Thailand, Bangkok; Chris M. Welbourn, Reading, Berkshire; Joanna Whalley, Victoria and Albert Museum, London; Honorary Diamond Member Bert Willems, Leica Microsystems, Wetzlar, Germany; Bear Williams, Stone Group Martin Rapaport Laboratories LLC, Jefferson City, Missouri, USA; J.C. (Hanco) Zwaan, National Museum of Natural History ‘Naturalis’, Leiden, The Netherlands. Honorary Life Members Anthony J. Allnutt, Hermann Bank, Content Submission Mary A. Burland, Terence M.J. The Editor-in-Chief is glad to consider original articles, news items, conference/excursion Davidson, Peter R. Dwyer-Hickey, reports, announcements and calendar entries on subjects of gemmological interest for Gwyn M. Green, Roger R. Harding, publication in The Journal of Gemmology. A guide to the preparation of manuscripts John S. Harris, J. Alan W. Hodgkinson, is given at www.gem-a.com/publications/journal-of-gemmology.aspx, or contact the John I. Koivula, Jack M. Ogden, Production Editor. C.M. (Mimi) Ou Yang, Evelyne Stern, Ian Thomson, Vivian P. Watson, Subscriptions Colin H. Winter Gem-A members receive The Journal as part of their membership package, full details of which are given at www.gem-a.com/membership.aspx. Laboratories, libraries, museums Chief Executive Officer and similar institutions may become Direct Subscribers to The Journal (see www.gem-a. James H. Riley com/publications/subscribe.aspx). Council Advertising Mary A. Burland, Jessica M. Cadzow- Enquiries about advertising in The Journal should be directed to the Marketing Consultant. Collins, Paul F. Greer, Alan D. Hart, Nigel B. Israel, Jonathan Lambert, For more information, see www.gem-a.com/publications/journal-of-gemmology/advertising- Richard M. Slater, Miranda E.J. Wells in-the-journal.aspx. Branch Chairmen Copyright and Reprint Permission Midlands – Georgina E. Kettle Abstracting with credit to the source, photocopying isolated articles for noncommercial North East – Mark W. Houghton classroom use, and photocopying by libraries for private use of patrons, are permitted. South East – Veronica Wetten Requests to use images published in The Journal should be directed to the Editor-in- South West – Richard M. Slater Chief. Give the complete reference citation and the page number for the image(s) in question, and please state how and where the image would be used. The Journal of Gemmology is published quarterly by Gem-A, The Gemmological Association of Great Britain. Any opinions expressed in The Journal are understood to be the views of the contributors and not necessarily of the publisher. Printed by DG3 (Europe) Ltd. ™ © 2015 The Gemmological Association of Great Britain Understanding Gems Cert no. TT-COC-002454 ISSN: 1355-4565 ii The Journal of Gemmology, 34(6), 2015 What’s New What’s New INSTRUMENTS AND TECHNIQUES Automated Melee Screening (AMS) Device spectroscopy. The system employs up to six differ- After several years in development, in early 2015 ent UV excitations plus a 405 nm (violet) laser, and The De Beers Group of Companies’ International contains optical components of the highest qual- Institute of Diamond Grading and Research re- ity. It permits the screening of up to 3,000 near- leased their diamond melee screening device to colourless diamonds per hour when used by a the broad diamond trade. The AMS device auto- well-trained technician. (To guarantee best results, matically tests colourless to near-colourless par- the system is non-automated, and the operator will cels. The samples are be able to efficiently