Volume 36/ No. 5/ 2019
Total Page：16
File Type：pdf, Size：1020Kb
Load more
Recommended publications
-
Finish, Culet Size, and Girdle Thickness: Categories of the GIA Diamond Cut Grading System
Finish, Culet Size, and Girdle Thickness: Categories of the GIA Diamond Cut Grading System This booklet summarizes the relationship of Finish, Culet Size, and Girdle Thickness to the GIA Cut Grading System for round brilliant diamonds. It is intended to help members of the jewelry trade better understand the attributes of diamond appearance, and how those attributes are evaluated within the GIA Cut Grading System. Finish—Polish and Symmetry In the GIA Cut Grading System for standard round brilliant To determine the relationship between finish and overall diamonds, finish (for Polish and Symmetry features) is cut quality, GIA conducted extensive observation testing factored into the final overall cut grade as follows: of numerous diamonds using standardized lighting and viewing conditions. Observations of diamonds with • To qualify for an Excellent cut grade, polish and comparable proportions, but differing in their polish and symmetry must be Very Good or Excellent. symmetry categories, were analyzed to determine the effects of finish on overall cut appearance. In this way, • To qualify for a Very Good cut grade, both polish GIA found that a one grade difference between the other and symmetry must be at least Good. aspects of a diamond’s cut grade and its polish and • To qualify for a Good cut grade, both polish and symmetry assessments did not significantly lower a symmetry must be at least Fair. trained observer’s assessment of face-up appearance, and could not be discerned reliably with the unaided eye— • To qualify for a Fair cut grade, both polish and e.g., polish and/or symmetry descriptions of Very Good symmetry must be at least Fair. -
Raman Investigations to Identify Corallium Rubrum in Iron Age Jewelry and Ornaments
minerals Article Raman Investigations to Identify Corallium rubrum in Iron Age Jewelry and Ornaments Sebastian Fürst 1,†, Katharina Müller 2,†, Liliana Gianni 2,†, Céline Paris 3,†, Ludovic Bellot-Gurlet 3,†, Christopher F.E. Pare 1,† and Ina Reiche 2,4,†,* 1 Vor- und Frühgeschichtliche Archäologie, Institut für Altertumswissenschaften, Johannes Gutenberg-Universität Mainz, Schillerstraße 11, Mainz 55116, Germany; [email protected] (S.F.); [email protected] (C.F.E.P.) 2 Sorbonne Universités, UPMC Université Paris 06, CNRS, UMR 8220, Laboratoire d‘archéologie moléculaire et structurale (LAMS), 4 Place Jussieu, 75005 Paris, France; [email protected] (K.M.); [email protected] (L.G.) 3 Sorbonne Universités, UPMC Université Paris 06, CNRS, UMR 8233, De la molécule au nano-objets: réactivité, interactions et spectroscopies (MONARIS), 4 Place Jussieu, 75005 Paris, France; [email protected] (C.P.); [email protected] (L.B.-G.) 4 Rathgen-Forschungslabor, Staatliche Museen zu Berlin-Preußischer Kulturbesitz, Schloßstraße 1 a, Berlin 14059, Germany * Correspondence: [email protected] or [email protected]; Tel.: +49-30-2664-27101 † These authors contributed equally to this work. Academic Editor: Steve Weiner Received: 31 December 2015; Accepted: 1 June 2016; Published: 15 June 2016 Abstract: During the Central European Iron Age, more specifically between 600 and 100 BC, red precious corals (Corallium rubrum) became very popular in many regions, often associated with the so-called (early) Celts. Red corals are ideally suited to investigate several key questions of Iron Age research, like trade patterns or social and economic structures. While it is fairly easy to distinguish modern C. -
Rhodochrosite Gems Unstable Colouration of Padparadscha-Like
Volume 36 / No. 4 / 2018 Effect of Blue Fluorescence on the Colour Appearance of Diamonds Rhodochrosite Gems The Hope Diamond Unstable Colouration of in London Padparadscha-like Sapphires Volume 36 / No. 4 / 2018 Cover photo: Rhodochrosite is prized as both mineral specimens and faceted stones, which are represented here by ‘The Snail’ (5.5 × 8.6 cm, COLUMNS from N’Chwaning, South Africa) and a 40.14 ct square-cut gemstone from the Sweet Home mine, Colorado, USA. For more on rhodochrosite, see What’s New 275 the article on pp. 332–345 of this issue. Specimens courtesy of Bill Larson J-Smart | SciAps Handheld (Pala International/The Collector, Fallbrook, California, USA); photo by LIBS Unit | SYNTHdetect XL | Ben DeCamp. Bursztynisko, The Amber Magazine | CIBJO 2018 Special Reports | De Beers Diamond ARTICLES Insight Report 2018 | Diamonds — Source to Use 2018 The Effect of Blue Fluorescence on the Colour 298 Proceedings | Gem Testing Appearance of Round-Brilliant-Cut Diamonds Laboratory (Jaipur, India) By Marleen Bouman, Ans Anthonis, John Chapman, Newsletter | IMA List of Gem Stefan Smans and Katrien De Corte Materials Updated | Journal of Jewellery Research | ‘The Curse Out of the Blue: The Hope Diamond in London 316 of the Hope Diamond’ Podcast | By Jack M. Ogden New Diamond Museum in Antwerp Rhodochrosite Gems: Properties and Provenance 332 278 By J. C. (Hanco) Zwaan, Regina Mertz-Kraus, Nathan D. Renfro, Shane F. McClure and Brendan M. Laurs Unstable Colouration of Padparadscha-like Sapphires 346 By Michael S. Krzemnicki, Alexander Klumb and Judith Braun 323 333 © DIVA, Antwerp Home of Diamonds Gem Notes 280 W. -
Pearls and Organic Gemstones
Pearls and Organic Gemstones INTRODUCTION Pearls were probably the first discovered gems of significance. Because they need no cutting or treatment to enhance their beauty and are rare natural occurrences, they have most likely always been highly esteemed. Organic gemstones are anything created by living processes. We have looked at amber in the past, but bone, teeth (such as ivory), and shells all have some value and are used today as gemstones. Pearls in General A pearl is grown by a mollusk (a bivalve such as a clam, oyster, or mussel or snail [single shell = valve]) in response to an irritant. Bivalves (two shelled mollusks) that secrete pearls live in both fresh‐ and saltwater. The irritant in most cases is a parasite (though it could be a grain of sand or other object). The parasite, a worm or other creature, is walled off by a secretion of calcium carbonate and protein. The calcium carbonate is the same as the inorganic material that makes stalactites in caves, and the protein is called conchiolin. The combination of these two substances (calcium carbonate and protein) makes the pearl's nacre (Nacre is also called mother of pearl). The nacre is a lustrous deposit around the irritant and forms concentric layers (overlapping circles). Many concentric layers of nacre build up over a period of a few years creating a pearl. The internal pattern is much like that seen in a jawbreaker. The layers create a sheen or luster that has iridescence and is described as both pearly luster and if colors of the rainbow are present, the pearl's orient. -
Palomar Gem & Mineral Club Newsletter
Palomar Gem & Mineral Club Newsletter August 2016 Volume 57 Issue 07 PGMC Annual Picnic We had our annual summer picnic last month at Jesmond Dene Park. As always Moni did a fine job of coordinating the event which included great food brought by everyone as well as a good time of comparing the fine rocks and gems we have found. We had a great slab swap between our members and everyone seemed to have a good time. As summer ends and we get ready to ramp up again, we hope everyone had a safe and productive summer. August is usually a down month for PGMC so that any specialty classes can take place at the shop and folks can go on vacation. We look forward to seeing everyone at the September meeting. Check out the rest of the newsletter for more information about September’s meeting as well as upcoming class schedules. We begin classes this week! 1 Textured Metal Class Come and join in the fun, learning to texture metal and make one-of-kind earrings (3 to 4 pairs) or a bracelet). They are great gifts. You may also learn how to make your own ear wires. Instructors: Diane Hall & Annie Heffner Location: Club Shop Dates: November 20, 2016 Time: 10am-4pm Fee: $35 plus supply cost (club membership required - $25 fee for single membership). You will need about 1 ounce of silver or copper sheet, which we will purchase for every one who is signed up by November 11th. Sign ups after that will need to provide their own material. -
The Wittelsbach-Graff and Hope Diamonds: Not Cut from the Same Rough
THE WITTELSBACH-GRAFF AND HOPE DIAMONDS: NOT CUT FROM THE SAME ROUGH Eloïse Gaillou, Wuyi Wang, Jeffrey E. Post, John M. King, James E. Butler, Alan T. Collins, and Thomas M. Moses Two historic blue diamonds, the Hope and the Wittelsbach-Graff, appeared together for the first time at the Smithsonian Institution in 2010. Both diamonds were apparently purchased in India in the 17th century and later belonged to European royalty. In addition to the parallels in their histo- ries, their comparable color and bright, long-lasting orange-red phosphorescence have led to speculation that these two diamonds might have come from the same piece of rough. Although the diamonds are similar spectroscopically, their dislocation patterns observed with the DiamondView differ in scale and texture, and they do not show the same internal strain features. The results indicate that the two diamonds did not originate from the same crystal, though they likely experienced similar geologic histories. he earliest records of the famous Hope and Adornment (Toison d’Or de la Parure de Couleur) in Wittelsbach-Graff diamonds (figure 1) show 1749, but was stolen in 1792 during the French T them in the possession of prominent Revolution. Twenty years later, a 45.52 ct blue dia- European royal families in the mid-17th century. mond appeared for sale in London and eventually They were undoubtedly mined in India, the world’s became part of the collection of Henry Philip Hope. only commercial source of diamonds at that time. Recent computer modeling studies have established The original ancestor of the Hope diamond was that the Hope diamond was cut from the French an approximately 115 ct stone (the Tavernier Blue) Blue, presumably to disguise its identity after the that Jean-Baptiste Tavernier sold to Louis XIV of theft (Attaway, 2005; Farges et al., 2009; Sucher et France in 1668. -
Painite, Cazrblllro,Rl: Its Crystal Structure and Relation To
American Mineralogist, Volume 61, pages 88-94, 1976 Painite, CaZrBlLlrO,rl: Its crystalstructure and relationto jeremejevite,Bu[[rAl6(OH)sO1r], and fluoborite, Br[Mgr(F, OH)rOr] Plur- BRre,uMooRE r.No TnreHnnu AnerI Department of the Geophysical Sciences, The Uniuersity of Chicago Chicago, Illinois 60637 Abstract Painite-CazrB[Al,O,s], hexagonalP6s, a :8.715(2), c : 8.472(2)A,Z : 2-possessesa rigid and dense [AlrO,r]'- octahedralframework, topologically identical to those found in jeremejevite, B'[IBAI6(OH)aO,,] and fluoborite, B,[Mg,(F,OH),O,]. R : 0.071 for l6l8 independent reflections. The octahedralframework is linked to [BOr]3 trianglesand [ZrOu]8-trigonal prismsatlf z and a largepipe at 0 0 z is cloggedwith compressed[CaO"]'0- octahedra. Average interatomic distancesareCa-O=2.398,2r-O:2.126,8-O:1.380,A1(l)-O: l.9l5,Al(2)-O: 1.918, and Al(3)-O : l.9l4A. The octahedral framework in painite, resistantto attack by acids and bases,suggests a highly refractoryphase and the possibilityof other equally resistantcompounds, hypothetical examplesbeing NaNbs+B[Alrors] and llUutB[Al"O,"]. ln the latter, thepipewould be lree from obstructions. Introduction Three-dimensionalsingle-crystal X-ray diffraction intensitiesabout the a2-rotation axis were collected Painite is a curious mineral species,first reported on a PnILnrn semi-automateddiffractometer with by Claringbull, Hey and Payne(1957) from the ruby graphite monochromatized MoKa, (tr : 0.70926A) minesof Mogok, Burma. It was found as a garnet-red radiation. With 2d-^* : 69.5", data were gathered 1.7 gram singlehexagonal crystal of hardness8. They through the k -- 0- to ll-levels. -
Download Lot Listing
IMPORTANT JEWELRY Wednesday, December 16, 2020 DOYLE.COM Lot 26 IMPORTANT JEWELRY AUCTION Wednesday, December 16, 2020 at 12pm Eastern VIEWINGS BY APPOINTMENT Please contact Laura Chambers to schedule your appointment: [email protected] Safety protocols will be in place with limited capacity. Please maintain social distance during your visit. LOCATION Doyle Auctioneers & Appraisers 175 East 87th Street New York, NY 10128 212-427-2730 DOYLE.COM Sale Info View Lots and Place Bids The journey of the Wilson family from the deep became intimate with “Old New York Society,” summering antebellum South to the pinnacle of New York with their new peers in Newport and traveling to Gilded Age society began with the marriage in 1852 London and Paris. Highlighting the December 16 of the enterprising Georgia-born Richard Thornton auction is an antique natural pearl and diamond tiara Wilson, the son of a tanner and shoemaker, to with provenance of Melissa Clementine Johnston Melissa Clementine Johnston, the daughter of a Wilson (lot 111). She is seen wearing the tiara in a prosperous Tennessee merchant and planter. With an portrait painted by French artist Léon Bonnat initial investment from his new father-in-law, Wilson’s (1833-1922). early business ventures flourished. During the Civil War, Wilson served in important roles in the office of The couple’s five children all made brilliant marriages, the Commissary-General of the Confederacy, traveling to aligning the Wilsons with the some of the most elite London to broker the Southern cotton crop. families of New York and Great Britain and earning Emerging from the war $500,000 richer, he began them the moniker, “The Marrying Wilsons.” buying up defunct railroads. -
Taaffeite, a New Beryllium Mineral, Found As a Cut Gem- Stone.I
765 Taaffeite, a new beryllium mineral, found as a cut gem- stone.I By B. W. ANDERSON,B.Sc., F.C.S., C. J. PAYNE, B.Sc. Laboratory of the Diamond, Pearl, and Precious Stone Trade Section of the London Chamber of Commerce. and G. F. CLARINGBULL,B.Sc., Ph.D., F.G.S. With microchemical analysis by M. H. HEY, M.A., D.Sc. Department of Mineralogy, British Museum. [Read June 7, 1951.] ------ N October 1945 Count Taaffe,2 a brilliant if unorthodox Dublin I gemmologist, in the course of examining a motley collection of gem- stones, came across a small mauve stone which puzzled him greatly. The stone had the appearance, and most of the characters, of spinel, but afforded clear evidence of double refraction. As recounted below, this stone was later found to belong to an entirely new mineral species-the only c~se hitherto known where a mineral has been first encountered as a faceted gem. Since the precise circumstances of such a discovery have both human and technical interest, it seemed best to obtain from Count Taaffe his own account of the event. This is accordingly given below before pro- ceeding to the more formal presentation of the data on the new mineral, which has been named taaffeite in honour of its discoverer. On one of my rounds in search of gems I came to Mr. Robert Dobbie, watchmaker and working jeweller in Fleet Street, Dublin; he allowed me in his genial way to go through all his boxes in which he kept stones, to pick out any that were real-most of them were glass-and to make him an offer for them. -
The New IMA List of Gem Materials – a Work in Progress – Updated: July 2018
The New IMA List of Gem Materials – A Work in Progress – Updated: July 2018 In the following pages of this document a comprehensive list of gem materials is presented. The list is distributed (for terms and conditions see below) via the web site of the Commission on Gem Materials of the International Mineralogical Association. The list will be updated on a regular basis. Mineral names and formulae are from the IMA List of Minerals: http://nrmima.nrm.se//IMA_Master_List_%282016-07%29.pdf. Where there is a discrepancy the IMA List of Minerals will take precedence. Explanation of column headings: IMA status: A = approved (it applies to minerals approved after the establishment of the IMA in 1958); G = grandfathered (it applies to minerals discovered before the birth of IMA, and generally considered as valid species); Rd = redefined (it applies to existing minerals which were redefined during the IMA era); Rn = renamed (it applies to existing minerals which were renamed during the IMA era); Q = questionable (it applies to poorly characterized minerals, whose validity could be doubtful). Gem material name: minerals are normal text; non-minerals are bold; rocks are all caps; organics and glasses are italicized. Caveat (IMPORTANT): inevitably there will be mistakes in a list of this type. We will be grateful to all those who will point out errors of any kind, including typos. Please email your corrections to [email protected]. Acknowledgments: The following persons, listed in alphabetic order, gave their contribution to the building and the update of the IMA List of Minerals: Vladimir Bermanec, Emmanuel Fritsch, Lee A. -
This Dissertation Has Been 62—2136 M Icrofilm Ed Exactly As Received GIELISSE, Peter Jacob M., 1934- INVESTIGATION of PHASE EQ
This dissertation has been 62—2136 microfilmed exactly as received GIELISSE, Peter Jacob M., 1934- INVESTIGATION OF PHASE EQUILIBRIA IN THE SYSTEM ALUMINA-BORON OXIDE-SILICA. The Ohio State University, Ph.D., 1961 M ineralogy University Microfilms, Inc., Ann Arbor, Michigan INVESTIGATION OP PHASE EQUILIBRIA IN THE SYSTEM ALUMINA-BORON OXIDE-SILICA DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of the Ohio State University By Peter Jacob M. Gielisse, M. S. The Ohio State University 1961 Approved by Adviser Department of Mineralogy ACKNOWLEDGMENTS The writer wishes to extend his sincere thanks to the many people without whose help the preparation of this dissertation would have been impossible. He is indebted in particular to his adviser, Dr. Wilfrid R. Foster, for his invaluable aid, advice and many kindnesses; to the other members of the faculty of the Department of Mineral ogy, Drs. Ernest G. Ehlers, Henry E. Wenden, and Rodney T Tettenhorst; and to his friend and colleague, Thomas J. Rockett. Acknowledgment is also made for financial support re ceived under contract No. AF 33(616)-3189, sponsored by Aeronautical Research Laboratories, Air Force Research Division, Wright Patterson Air Force Base, Ohio; as well as for aid received through a Mershon National Graduate Fellowship awarded to the writer by the Mershon Committee on Education in National Security for 1960-‘61'. It goes without saying that he is also most grate ful to his wife, Anna, for her excellent help and encour agement over the years. TABLE OF CONTENTS Page INTRODUCTION ...................................... -
1469 Vol 43#5 Art 03.Indd
1469 The Canadian Mineralogist Vol. 43, pp. 1469-1487 (2005) BORATE MINERALS OF THE PENOBSQUIS AND MILLSTREAM DEPOSITS, SOUTHERN NEW BRUNSWICK, CANADA JOEL D. GRICE§, ROBERT A. GAULT AND JERRY VAN VELTHUIZEN† Research Division, Canadian Museum of Nature, P.O. Box 3443, Station D, Ottawa, Ontario K1P 6P4, Canada ABSTRACT The borate minerals found in two potash deposits, at Penobsquis and Millstream, Kings County, New Brunswick, are described in detail. These deposits are located in the Moncton Subbasin, which forms the eastern portion of the extensive Maritimes Basin. These marine evaporites consist of an early carbonate unit, followed by a sulfate, and fi nally, a salt unit. The borate assemblages occur in specifi c beds of halite and sylvite that were the last units to form in the evaporite sequence. Species identifi ed from drill-core sections include: boracite, brianroulstonite, chambersite, colemanite, congolite, danburite, hilgardite, howlite, hydroboracite, kurgantaite, penobsquisite, pringleite, ruitenbergite, strontioginorite, szaibélyite, trembathite, veatchite, volkovskite and walkerite. In addition, 41 non-borate species have been identifi ed, including magnesite, monohydrocalcite, sellaite, kieserite and fl uorite. The borate assemblages in the two deposits differ, and in each deposit, they vary stratigraphically. At Millstream, boracite is the most common borate in the sylvite + carnallite beds, with hilgardite in the lower halite strata. At Penobsquis, there is an upper unit of hilgardite + volkovskite + trembathite in halite and a lower unit of hydroboracite + volkov- skite + trembathite–congolite in halite–sylvite. At both deposits, values of the ratio of B isotopes [␦11B] range from 21.5 to 37.8‰ [21 analyses] and are consistent with a seawater source, without any need for a more exotic interpretation.