 | | Journal (issue) | | The Cheapside Hoard: An Extraordinary Collection of Jewels Digit Patterns in Opal Agate from Morocco Field...Field Report on Oregon Sunstone Fall 2013 VOLUME 49, No. 3 EDITORIAL 125 Striving for Timeliness...129 138 On the Origin of Digit Patterns in Gem Opal Benjamin Rondeau, Jean-Pierre Gauthier, Francesco...this finger-like feature, mostly found in Ethiopian opal, and proposes a multi-step model for its formation...pg. 162 FIELD REPORT 162 Three Occurrences of Oregon Sunstone Duncan Pay, Robert Weldon, Shane McClure |  | | Journal (article/letter/editorial) | | minerals Article A Review of the Classification of Opal with Reference to Recent New Localities Neville...Abstract: Our examination of over 230 worldwide opal samples shows that X-ray diffraction (XRD) remains...of opal-A, opal-CT and opal-C, though we found that mid-range infra-red spectroscopy provides an acceptable...provenance. The corpus of results indicated that the opal-CT group covers a range of structural states and...At the one end are the opal-CTs that provide a simple XRD pattern (“simple” opal-CT) that includes Ethiopian |  | | Journal (article/letter/editorial) | | minerals Article Silicification of Wood: An Overview George E. Mustoe Geology Department, Western Washington...Washington University, Bellingham, WA 98225, USA; mustoeg@wwu.edu Abstract: For many decades, wood silicification...generalization. Keywords: silicification; fossil wood; opal-A; opal-CT; chalcedony; quartz 1. Introduction Citation:...Citation: Mustoe, G.E. Silicification of Wood: An Overview. Minerals 2023, 13, 206. https://doi.org/ 10...Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and |  | | Journal (issue) | | Feature Articles 490 Green-Luminescing Hyalite Opal from Zacatecas, Mexico By Emmanuel Fritsch, Peter...colour appearance of this rough and cut hyalite opal from Zacatecas, Mexico, is due to its green daylight-induced...Laguna Beach, California, USA. Photo by Orasa Weldon. 532 Conferences Sinkankas Opal Symposium|AGA Las Vegas|Mallorca...Edward Boehm, RareSource, Chattanooga, Tennessee, USA; Alan T. Collins, King’s College London; John L....Emmett, Crystal Chemistry, Brush Prairie, Washington, USA; Emmanuel Fritsch, University of Nantes, France; |  | | Report (issue) | | Contents 4 Map: Notable Opal Localities 50 BY BRUCE PAUL GABER 6 The Opal Enigma: Science, History...and Pins Afire: Play of Color in Opal BY MAX WEIBEL Sparkling Opal in Ancient Bones: Precious Relics...vibrant with opal pattern and color. In this extreme close-up of a Lightning Ridge black opal, the field...approximately 3 mm wide. Opal courtesy Jenni Brammall BY ALEX RITCHIE 52 An Opal Glossary of Terms BY...BY SI AND ANN FRAZIER BY PETER HUBER 64 Opal from Mexico: Unsurpassed Fire BY JURGEN SCHUTZ 18 Perfect |  | | Journal (issue) | | colors of Australian opal come to us through the courtesy of the Opal Spectrum company. For details,...Our Cover feature. And, for a fascinating look at opal mining , plus more pictures, turn to page 8. AND...TX 78745 4 - JANUARY 1977 HOW TO CUT BRAZILIAN OPAL lapidary techniques for a new material by W.L Maison...and Barbara Thomas 32 TIPS ON BUYING AND CUTTING OPAL Advice from the professionals 34 ART NOUVEAU Easy-to-do...Gunther FEATURES 8 COO BER PEDY TODAY A visit to the opal mines by Lee Cross 15 INTERNAL STRUCTURES AND |  | | Journal (article/letter/editorial) | | Article 29 Si Solid-State NMR Analysis of Opal-AG, Opal-AN and Opal-CT: Single Pulse Spectroscopy and Spin-Lattice...A. 29 Si Solid-State NMR Analysis of Opal-AG, Opal-AN and Opal-CT: Single Pulse Spectroscopy and Spin-Lattice...spectroscopy offers an additional method of characterisation of opal-A and opal-CT through spin-lattice...spin-lattice (T1 ) relaxometry. Opal T1 relaxation is characterised by stretched exponential (Weibull) function...of the curve) parameters. Relaxation is at least an order of magnitude faster than for silica glass and |  | | Journal (article/letter/editorial) | | ); Allan.Pring@flinders.edu.au (A.P.) Abstract: An extensive infrared (IR) spectroscopy study using...was undertaken to characterise opal-AG, opalAN (hyalite), opal-CT and opal-C, focussing on the Si-O fingerprint...spectroscopy shows that the three major IR bands of opal are split into transverse optical (TO) and longitudinal...rather than heterogeneity or particle size effects. An alternative use of ATR using unpowdered samples provides...non-destructive delineation of play of colour opals into opal-AG or opal-CT gems. We find that there are no special |  | | Book (edition) | | of meriting the acceptance of this Dictionary as an international reference source for the gemological...against overwhelming odds directed the early growth of an unique institution. As in the educational development...by the definition. For example: “African jade’ is an incorrect term for green grossularite, as stated...The dictionary’s use as a gemological directory. An effort has been made to include the names, descriptions...(ab”a-lo’nee). The mollusc Haliotis, also known as an ormer or ear-shell. From Pacific waters of California |  | | Journal (issue) | | PRICES ARE BASED AT $180.00 per ounce, we will make an adjustment of price on day order is shipped. Prices...rockhounds. Elsewhere in this issue, you will find an article about some of the many uses for this versatile..................... 16 A Method for Using Tecopa Opal by F.W. Seasholtz .................................. 58 Mrs. Joan Pichotta. Secretary 805 Spring Lake. Bedford. TX 76021 M rs. Sandy Dudley. Treasurer...less than 14"x27". The standard Genie comes with an 80 and 220 grit 6"x1~ Galaxy metal-bond diamond grinding |  | Chauviré, Boris, Mollé, Valentin, Guichard, Florine, Rondeau, Benjamin, Thomas, Paul Stephen, Fritsch, Emmanuel (2023) Cracking of Gem Opals. Minerals, 13 (3) 356 doi:10.3390/min13030356 | Journal (article/letter/editorial) | | whitening or cracking. To understand the latter, 26 opal samples were investigated and separated into 2 groups...“water-stored” opal samples, which are stored in water after extraction, and “air-stored” opal samples, which... Citation: Chauviré, B.; Mollé, V.; Keywords: opal; cracking; water; TGA; drying; shrinkage; decrepitation...Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and...studies have shown that “whitening“ is correlated with an increase in porosity and a reorganization of the |  | | Book | | recognized as an authority in the lapidary field. Beginning with a description of agate, he proceeds to an interesting...ties and forms of quartz gems other than agate, opal and its varieties, and petrified wood a great favorite...tell abot1t otl1er Cttiartz varieties st1ch as the opal, jasper, ancl petrified wood; a11d to give l1in1...received, and one al,vays fears that the na111e of an in1portant aclviser may be left out. Ho,vever, in...12 were also const1lted. Nlany other sot1rces in an extensive library on the st1bject were const1lted |  | | Journal (issue) | | Phenomenon | Zircon Inclusions in Emeralds from Lake Manyara, Tanzania | Large Euclase, Reportedly from...Zimbabwe | Chromiumbearing Translucent Green Common Opal | Blue Sapphires Reportedly from Azad Kashmir |...Silica Glass Sold as RockCrystal Balls | An Unusual Pink Synthetic Opal | Quench-Fractured Bicoloured Synthetic...courtesy of The Walters Art Museum 119 172 Hyalite Opal from Erongo, Namibia, Showing Green Daylight Fluorescence...Cambridge, Massachusetts, USA Edward Boehm RareSource, Chattanooga, Tennessee, USA Maggie Campbell Pedersen |  | | Journal (issue) | | SEPTEMBER 2020 38 PENNSYLVANIA’S PEQUEA SILVER MINE 10 Agate Origins and Formation Natural Treasures...Illustrious Opals 28 GOLDEN ANNIVERSARY GOODNESS Lake Havasu Gem & Mineral Society Marks 50 Years By Helen... so I only walked out where he suggested, to get an idea of what’s there. I walked out maybe 75 yards...83642 Show Room Now Open! M-F 7:30-4:00 MST NEW OPAL SHIPMENT IN FROM ETHIOPIA THIS MAY BE THE BRIGHTEST...COLORFUL AA & AAA GRADE OPAL. PLEASE SEE OUR WEBSITE FOR NEW LISTINGS OF THIS OPAL THE VILLAGE SMITHY OPALS | | | Book | | THE BOOK OF yJ An>> aT -v • J[. Illustrated. $9.^5 ISBN 0-8019-0964-3 OF VERMONT ENT OF LIBRARIES...as an authority in the lapidary field. Beginning with a description of agate, he proceeds to an interesting...varieties, with favorite location of quartz agate, opal wood — collectors. The petrified gems throughout... tell about other quartz varieties such as the opal, and petrified wood; and to give him the most complete...received, and one always fears that the name of an important adviser may be left out. However, in the |  | | Journal (issue) | | Porter, Treasurer P.O. Box 96, Burbank, CA 91503 Opal Enthusiasts Hold First Seminar ...................per lb. NEWI Plume Opal is another new discovery in Mexico! This beautiful plume opal is hand-selected...turquoise .from the Little Gem Mine (also known as the Cracker Jack Mine) in Nevada. It comes in two types:...famous old-time Mexican lavender lace agate. The mine producing this has been closed for some time. but...enough to cut these. we will cut them for you. Include an additional cutting fee of $3.00 for each one cut |  | | Journal (issue) | | pyrope-spessartine-grossular garnet • New plastic opal imitation from Kyocera • Natural blister pearl from...“bimineralic” inclusion in diamond • Agate-like banding in opal • Dendritic inclusion in Cambodian sapphire • Green...Australian opal outlook • Indonesian opal • Cultured pearl update • Secondary gem market • Oregon sunstone...Mouawad Campus 5345 Armada Drive Carlsbad, CA 92008 USA © 2018 Gemological Institute of America All rights...samples from GIA’s research database, the authors offer an unrivaled gemological characterization of these remarkable |  | | Journal (issue) | | the U.S.A. 05 0 74470 02033 2 UNM’s HARDING MINE Exploring Plentiful Pegmatite 2 ROCKNGEM.COM ...With WorldWide Popularity 20 NEW MEXICO’S HARDING MINE The Must-See Pegmatite of the West Steve Voynick...received a shipment of High Grade Welo opal from Ethiopia-posting new opal parcels daily. Please call or order...TOURMALINE with ALBITE and QUARTZ Himalaya Mine, San Diego County, CA Watercolor by Frederick C. Wilda©...2020 7 Covington Has Moved! ROYAL PEACOCK OPAL MINE Dig your own Virgin Valley Fire Opals ALL YOU |  | | Book (edition) | | of meriting the acceptance of this Dictionary as an international reference book for the gemological...by the definition. For example: "African jade" is an incorrect term for green grossularite, as stated..."a" alone should be sounded as the "a" in "cat/* An "e" following a vowel indicates a long sound for...emphasis. dictionary's use as a gemological directory. An effort has been made to include in alphabetical order...(ab"a-lo'nee). The mollusc Haliotis, also known as an ormer or ear-shell. From Pacific waters of California |  | | Book (edition) | | gemstone, strikes any boundary of that gemstone at an angle greater than its critical angle. Total reflection...totally reflected until it strikes a boundary at an angle less than the critical angle, in which event...(3rd Edition, Revised 1944) by Robert M. Shipley. An Encyclopedia of Gems (1944) by Henry E. Briggs. Dictionary...of meriting the ac¬ ceptance of this Dictionary as an international reference book for the gemological...by the definition. For example: “African jade” is an incorrect term for green grossularite, as stated |  | Swayze, G. A., Clark, R. N., Goetz, A. F. H., Livo, K. E., Breit, G. N., Kruse, F. A., Sutley, S. J., Snee, L. W., Lowers, H. A., Post, J. L., Stoffregen, R. E., Ashley, R. P. (2014) Mapping Advanced Argillic Alteration at Cuprite, Nevada, Using Imaging Spectroscopy. Economic Geology, 109 (5) 1179-1221 doi:10.2113/econgeo.109.5.1179 | Journal (article/letter/editorial) | | hydrothermal alteration. Partial lichen cover on opal spectrally mimics chalcedony, limiting its detection...Kerr et al., 2011). Spectroscopy is also playing an increasing role in analyses of alteration in drill...near-infrared (VIS-NIR or VNIR-SWIR) 0.4- to 2.5-μm range is an effective tool for evaluating subtle patterns of...Stonewall Mountain Hi 37 o 30' Figure 2 Cuprite o an yo n Inferred caldera margin 266 117 15' ck Pa...north from the Las Vegas area to south central Oregon (Stewart, 1988; inset Fig. 1), which separates |  | | Journal (issue) | | originated from the same crystal. 90 Play-of-Color Opal from Wegel Tena, Wollo Province, Ethiopia Benjamin...Gaillou Describes a major new source of high-quality opal with a mostly white bodycolor. Carat Points NOTES...Turquoise Gagan Choudhary 114 New Occurrence of Fire Opal from Bemia, Madagascar Martina Simoni, Franca Caucia...as a speaker or a poster presenter, please submit an abstract no later than January 10, 2011. Guidelines...time. The original ancestor of the Hope diamond was an approximately 115 ct stone (the Tavernier Blue) that |  | | Journal (issue) | | Anthony R. Kampf Los Angeles, CA Robert E. Kane Lake Tahos, NV John I. Koivula Santa Monica, CA Henry...Lebanon, N{ Ray Page Santa Monica, CA George Rossn~an Pasadena, CA Kenneth Scarratt London, United Kingdom...transparent labradorite feldspar found to date only in Oregon. We applaud this type of dialogue. In gemology...either by control of the new source or by access to an important market segment, can assign a name of their...in the 1970s. We at Gems o)Gemology have supported an author's right to use a term that has a reasonable |  | | Journal (issue) | | kyanite from Tanzania|Green daylight-fluorescent opal from Mexico|‘Trapiche’ quartz with radiating fibres|Yellow...amazonite|News from Myanmar Cover Photo: An 11.38 ct diamond with an asteriated hydrogen cloud is photographed...ARTICLES Feature Articles 306 The Rhodesian Star: An Exceptional Asteriated Diamond By Thomas Hainschwang...Edward Boehm, RareSource, Chattanooga, Tennessee, USA; Alan T. Collins, King’s College London; John L....Emmett, Crystal Chemistry, Brush Prairie, Washington, USA; Emmanuel Fritsch, University of Nantes, France; |  | | Journal (issue) | | Johne FGA, L Joyner PhD FGA, H Kitawaki FGA CGJ, R J Lake FGA DGA, Li Li Ping PhD FGA DGA, M A Medniuk FGA...presence or absence of a bead. Figure 2 provides an overview, illustrating sectioned cultured pearls...Figure 1: The pearl farm in North Bali, an aquacultural business with an ultra-modern approach to oyster production...host animals for the cultured pearls. Both halves of an oyster’s shell have a layer of soft skin. This tissue...purpose of growing a cultured pearl. The body of an oyster selected as a host animal has two sites where |
|
