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| / Volume 34 / No. 6 Columns p. 476 467 What’s New Automated melee screening device|DFI Mid-UV Laser+...Newsletter|Microcrystalline silica online lectures|What’s New in the Mineral World? 470 Practical Gemmology A... 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 |
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| ); 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 |
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| 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 |
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| Electric Opal Geology and Mineralogy of TM Green Daylight-Luminescing Hyalite Opal from Zacatecas,...Figure 1. Green daylightluminescing hyalite opal, Electric Opal 3.2 cm tall, from Zacatecas Mexico. Peter...October 2013, five weathered specimens of botryoidal opal rough showing moderate green daylight luminescence...of Opal Mesa. The little knob in the middle of the view on top of the long flat mesa is the opal location...in ruggedness to the left; this is the margin of an eruption vent on the caldera ring fracture zone. |
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| Nigeria Volume 38 / No. 2 / 2022 COLUMNS What’s New 111 III Conferenza Nazionale Diamante e Gemme di...weight) and 272 pavé diamonds. Courtesy of IVY New York. ARTICLES 138 Spinel from the Pamir Mountains...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 |
 | Gaillou, E., Fritsch, E., Aguilar-Reyes, B., Rondeau, B., Post, J., Barreau, A., Ostroumov, M. (2008) Common gem opal: An investigation of micro- to nano-structure. American Mineralogist, 93 (11) 1865-1873 doi:10.2138/am.2008.2518 | Journal (article/letter/editorial) |
| Volume 93, pages 1865–1873, 2008 Common gem opal: An investigation of micro- to nano-structure EloïsE...The microstructure of nearly 200 common gem opal-A and opal-CT samples from worldwide localities was investigated...market for their intrinsic body color. Common opal-AG and opal-CT are primarily built from nanograins that...~25 nm in diameter. Only opal-AN has a texture similar to that of glass. In opal-AG, nanograins arrange...layers, or in some cases, radial structures. Common opal does not diffract light because its spheres exhibit |
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| 515 Narragansett Park Drive, Pawtucket, RI 02861 USA • 1/8 HP / 22,000 rpm motor • Foot control and handpiece...68 30 26 38 Green Daylight-Fluorescing Hyalite Opal materials by Terri Haag 62 44 Trends: Pearls by...by Eva M. Sherman Screamin’ Green Fluorescent Opal NEW! 54 Wire Wrapped Carnelian Pendant ® p. 38...EDITORIAL DIRECTOR Merle White 4 APRIL 22 IS EARTH DAY, an annual celebration of our planet since 1970, the...Nixon. Both events were outgrowths of concerns about an increasingly powerful human impact on the environment |
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| Mineral and Gem Museum; Dr. Marian Lupulescu, New York State Museum; Dr. George Robinson, Michigan Technological...Adrian College; and Dr. Steven C. Chamberlain, New York State Museum. Sixteen abstracts were submitted...and Environmental Sciences, University of New Orleans, New Orleans, LA 70148. The Alta Stock is one of...absence of iron as a chromophore has resulted in an unusual completely white mineral assemblage. Additionally...formation of ludwigite near the intrusive contact, an uncommon mineral in contact-metamorphic assemblages |
 | Gehlen, M., Beck, L., Calas, G., Flank, A.-M., Van Bennekom, A.J., Van Beusekom, J.E.E. (2002) Unraveling the atomic structure of biogenic silica: evidence of the structural association of Al and Si in diatom frustules. Geochimica et Cosmochimica Acta, 66 (9) 1601-1609 doi:10.1016/s0016-7037(01)00877-8 | Journal (article/letter/editorial) |
| Copyright © 2002 Elsevier Science Ltd Printed in the USA. All rights reserved 0016-7037/02 $22.00 ⫹ .00 Pergamon...consequences for the use of sedimentary biogenic silica as an indicator of past environmental conditions. Copyright...1% (Van Bennekom et al., 1989, 1991), compared to an average diatom Al/Si ratio of 1/1000 (Martin and...there is to date no conclusive evidence for the opal synthesized by diatoms. A straightforward analogy...environment. Cultured diatoms were chosen to provide an end-member of known particle history on which the |
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| hyalite (opal-AN), silica sinters, and synthetic silica gels and silicic acid. Pulse delays of up to an hour...secondary phase in various geological environments. Opal is common in neutral-pH hydrothermal settings, where...reported an additional, smaller peak due to silicons with single attached OH groups (Q3) in some opal-CT samples...The result of such differential relaxation will be an accentuation of the peak areas Q3 and Q2 in spectra...Although the cone itself only occasionally produces new lava flows, it has continuously produced a plume |
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| a series of questions on the gem with answers. Opal: An 8 page brochure consisting of a series of questions...Inc., House of Stoner. 22 W. 48th St., New York, N. Y. NEW YORK eEM DEALER DROWNS MinetaloJical circles...its most popular gem dealers, Stephen vanii of New York City. No one seems to konw how the accident happened...guardrail to fall anto the Hudson River, 30 feet deep. New York harbor police, local officials and the Lackawanna...the Stephen Varni Co., of 580-584 Fifth Ave., New York City, and was well known allover the country due |
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| PrePub Article 2 Near infrared signature of opal and chalcedony as a proxy for their structure and...RONDEAU and NICOLAS MANGOLD 1 4 Abstract: Opal-A, opal-CT and chalcedony develop in various geological...emphasizes that several new spectroscopic criteria distinguish opal-A, opal-CT and chalcedony: the apparent...shape of the molecular-water band, quantified by a new criterion developed here (concavity-ratio criterion...structure (–A or CT). This new method quickly assesses the geological conditions of opal formation (on Earth |
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| Australian Opal Symposium & Updates Padparadscha Coloration Pantone's Color of the Year Latest Auction...Winter 2019 InColorMagazine.com; Gemstone.org NEW LOCATION LAS VEGAS CONVENTION CENTER WE’LL GET YOU...Busy Year for ICA Editor’s Note The Bridge to the New Year ICA Report 26 Activities of ICA Members Around...01-carat gem black opal recently mined at Lightning Ridge. (Photo and stone courtesy of Cody Opal Australia)...Industry InColor Special Opal Issue The 9th Annual National Opal Symposium Opal Classification: The Best |
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| excellence in the trade. Sign up now and receive our NEW fully illustrated Diamond Diploma course notes —...Volume 34 / No. 4 COLUMNS p. 35 279 What’s New GemmoFtir|GSJ abstracts| Historical facet designs|ICGL...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 |
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| Printed in Great Britain CONTRIBUTIONS OF FOREST OPAL AND ASSOCIATED CR YST ALLINE PHASES TO FINE SILT...(SEM) is useful in the identification of biogenic opal. Opaline spheres, cups, and scrolled or convoluted...aggregate e~tinction. Between 2/ 3 and 3/4 of the total opal isola te from deciduous tree leaves was solubilized...species. Biogenic opal of forest origin was about 10-15 times more soluble than grass opal, which probably...higher specific surface of the former. INTRODUCTION Opal is commonly considered a hydrated amorphous silicate |
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| Publications P.O. Box 13384 Los Angeles, CA 90013-0384 USA (Include a self-addressed, stamped envelope with...Price Factors in a Nutshell 9 Why the 4 C’s is Not an Adequate Pricing System Price Factors Explained 10...Malachite 47 Moonstone & Some Other Feldspars 47 Opal 49 Peridot 53 Ruby & Sapphire 54 Spinel 57 Tanzanite...Debit Cards 111 When Problems Arise 112 14. Choosing an Appraiser 115 How to Find a Qualified Independent...necessarily indicative of a deal. Why the 4 C’s is Not an Adequate Pricing System You may be surprised that |
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| Abstract: The formation of ordered particle arrays plays an essential role in nanotechnology, biological systems...reveals that particle morphologies trace the flow of opal-forming colloidal suspensions and document syn-...replacement of non-silicate minerals proceeds via an interface-coupled dissolution precipitation process...clastic sediments. Keywords: silica; opal-A; common opal; precious opal; silica colloid; photonic crystal;...microscopy shows that nanosphere-based amorphous silica (opal-A) in central Australia consists of subparticles |
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| Thessaloniki Bahrain Greece Ian Graham The University of New South Wales Australia Editorial Office MDPI St. Alban-Anlage...in Adamello Massif, Central Southern Alps, Italy: An Investigation of Its Mineralogy, Crystallography...A Review of the Classification of Opal with Reference to Recent New Localities Reprinted from: Minerals...refereed journals, is the co-author of 4 IMA-approved new mineral species, and has co-authored three books...International Mineralogical Association has adopted a new mineral name in his honor (Voudourisite). Stefanos |
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| Mineral New The Mineral Collector's Vol. 24 No. 4 April 2008 Newsletter $3.00 Tucson 2008 Never to...historic pieces from assorted localities in the USA. Pieces selected from the American Philosophical...(Continues on page 3 Opal Claudeen Chisholm & Bill Shelton laeliason@msn.com The Name. Opal, at least the word...necessarily was used to refer to the gem we know today as opal. The first use in English is attributed to Philemon...■ Opale French ■ Opal English History. One source indicates several very early opal discoveries including |
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| Collector's View of NEW ZEALAND MARK C. B L A Z E K New Mexico Tech Socorro, New Mexico 87801 Introduction...minerals would you ex pect to find in a country like New Zealand? Dia monds, rubies, emeralds, and opals...might associate that everelusive mineral, gold, with New Zealand. The point is simply this: the average American...general location and variety of minerals found in New Zealand. It is not intended to be detailed and exhaustive...countries. When I read of a New Zealand rockhound who wanted to corres pond with an American rockhound, I |
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| 3749/canmin.46.1.139 THE FORMATION OF PRECIOUS OPAL: CLUES FROM THE OPALIZATION OF BONE Benjamath PEWKLIANG...analyses show that the opalized bones are composed of opal-AG and quartz. Major- and minor-element XRF analyses... The opal is depleted in all trace elements relative to PAAS. During the formation of the opal, the coarser...enlarged and filled with chalcedony, which postdates opal formation. These chemical and microstructural features...the opal forming first as a gel in the small cavities left by the osteons, and the individual opal spheres |
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| Sterling Jewelry 62 West 47th Street, Suite 905, New York, NY 10036 Tel: 212.391.5649 Fax: 917.595.5312...Rings in white gold and diamonds with Ethiopian opal center stones by Van Cleef & Arpels. (Photo: Van...Dear Readers, T 36 West 44th Street, Suite 914 New York, NY 10036 Tel: 1-212-620-0900, Fax: 1-212-352-9054... ISSN: 1158934X To Subscribe to InColor, send an email to: ica@gemstone.org www.gemstone.org he...tremendous growth in their local markets. While the USA, Japan, and Europe have mainly seen declining consumption |
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| mmigration Ol ice. Opal Mines, Wbite Cllifs, New South Wales. Oourte8JI Special Opal Nuinber Granite and...magazine• .'-============================ r ROCH. S an d MINERALS A NON-TECHNICAL MAGAZINE --'ON-MINI...1Iuseum. B y 1rilli<1m F. Foshag The Geology of Opal. By, Oilb rrt Hart.. . . . . . . . . . . . . . ...Quest of the Opal. B!I If. T. Strnng.. . ....................... . . ('(}Jor Play in Opal. B.11, Il. E... . . . . . . . . . . . . . . . . . . . . . 'fbe Opal. JJy E11,qe11e Jr. B1"11k..................... |
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| . ARTHUR CHAMBERLAIN , Editor . Member of the New York heralogical Club and of the Brooklyn Institute...sciences , NO . 4 - JUNE , 1898 . CONTENTS AsbestUS , OPAL FIELDS OF AUSTRALIA , HALITE FACT AND FANCY , GEORGE...26 JOHN ST . , NEW YORK THE MINERAL COLLECTOR . CROCOITE . A rare species from a new locality . Magnificent...: tainty of your approval . Send for descriptive New Arrival List . " OS DO The Complete Mineral Catalogue...and form of all known species and varieties , with an up - to - date supplement . A Metallic Classification |
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| are un-fossiliferous. tho!\e found actually in the opal-bearing beds are harder. rounuer and more water...bowlders also contain proof of the deposition of opal during a very extended period, as 1 have obtained...among them sOllie which show that they have had opal introduced into them while in a state of considemble...together by opal, the portions of the bowlder having in some cases shifted a quarter of an inch or so...of the period of opal deposition. I may men tion that fully 95 pel' cent. of the opal obtained on the |
