Ecological Comparison of Synthetic Versus Mined Diamonds
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ASX Market Announcements Australian Securities Exchange SYDNEY NSW 2000 13 September 2012 Dear Sir, Attached Is a Presentati
120 Collins Street Melbourne 3000 Australia Postal Address: GPO Box 384D Melbourne 3001 Australia T +61 (0) 3 9283 3333 F +61 (0) 3 9283 3707 ASX Market Announcements Australian Securities Exchange SYDNEY NSW 2000 13 September 2012 Dear Sir, Attached is a presentation given by Alan Davies, Chief executive, Rio Tinto Diamonds & Minerals, Bruce Cox, Managing director, Rio Tinto Diamonds, Jean-Francois Turgeon, Managing director, Rio Tinto Iron & Titanium and Xiaoling Liu, President and Chief executive, Rio Tinto Minerals, as part of a financial community visit in Montreal, Canada. Yours faithfully, Stephen Consedine Company Secretary Registered in Australia Rio Tinto Limited 120 Collins Street Melbourne 3000 Australia ABN 96 004 458 404 Rio Tinto Diamonds & Minerals Fuelling consumer-driven economic growth Alan Davies Chief executive 12 September 2012 Cautionary statement This presentation has been prepared by Rio Tinto plc and Rio Tinto Limited (“Rio Tinto”) and consisting of the slides for a presentation concerning Rio Tinto. By reviewing/attending this presentation you agree to be bound by the following conditions. Forward-looking statements This presentation includes forward-looking statements. All statements other than statements of historical facts included in this presentation, including, without limitation, those regarding Rio Tinto’s financial position, business strategy, plans and objectives of management for future operations (including development plans and objectives relating to Rio Tinto’s products, production forecasts and reserve and resource positions), are forward-looking statements. Such forward-looking statements involve known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements of Rio Tinto, or industry results, to be materially different from any future results, performance or achievements expressed or implied by such forward- looking statements. -
Spring 1998 Gems & Gemology
VOLUME 34 NO. 1 SPRING 1998 TABLE OF CONTENTS EDITORIAL 1 The Dr. Edward J. Gübelin Most Valuable Article Award FEATURE ARTICLE 4 The Rise to pProminence of the Modern Diamond Cutting Industry in India Menahem Sevdermish, Alan R. Miciak, and Alfred A. Levinson pg. 7 NOTES AND NEW TECHNIQUES 24 Leigha: The Creation of a Three-Dimensional Intarsia Sculpture Arthur Lee Anderson 34 Russian Synthetic Pink Quartz Vladimir S. Balitsky, Irina B. Makhina, Vadim I. Prygov, Anatolii A. Mar’in, Alexandr G. Emel’chenko, Emmanuel Fritsch, Shane F. McClure, Lu Taijing, Dino DeGhionno, John I. Koivula, and James E. Shigley REGULAR FEATURES pg. 30 44 Gem Trade Lab Notes 50 Gem News 64 Gems & Gemology Challenge 66 Book Reviews 68 Gemological Abstracts ABOUT THE COVER: Over the past 30 years, India has emerged as the dominant sup- plier of small cut diamonds for the world market. Today, nearly 70% by weight of the diamonds polished worldwide come from India. The feature article in this issue discuss- es India’s near-monopoly of the cut diamond industry, and reviews India’s impact on the worldwide diamond trade. The availability of an enormous amount of small, low-cost pg. 42 Indian diamonds has recently spawned a growing jewelry manufacturing sector in India. However, the Indian diamond jewelery–making tradition has been around much longer, pg. 46 as shown by the 19th century necklace (39.0 cm long), pendant (4.5 cm high), and bracelet (17.5 cm long) on the cover. The necklace contains 31 table-cut diamond panels, with enamels and freshwater pearls. -
Global Rough Diamond Production Since 1870
GLOBAL ROUGH DIAMOND PRODUCTION SINCE 1870 A. J. A. (Bram) Janse Data for global annual rough diamond production (both carat weight and value) from 1870 to 2005 were compiled and analyzed. Production statistics over this period are given for 27 dia- mond-producing countries, 24 major diamond mines, and eight advanced projects. Historically, global production has seen numerous rises—as new mines were opened—and falls—as wars, political upheavals, and financial crises interfered with mining or drove down demand. Production from Africa (first South Africa, later joined by South-West Africa [Namibia], then West Africa and the Congo) was dominant until the middle of the 20th century. Not until the 1960s did production from non-African sources (first the Soviet Union, then Australia, and now Canada) become impor- tant. Distinctions between carat weight and value affect relative importance to a significant degree. The total global production from antiquity to 2005 is estimated to be 4.5 billion carats valued at US$300 billion, with an average value per carat of $67. For the 1870–2005 period, South Africa ranks first in value and fourth in carat weight, mainly due to its long history of production. Botswana ranks second in value and fifth in carat weight, although its history dates only from 1970. Global production for 2001–2005 is approximately 840 million carats with a total value of $55 billion, for an average value per carat of $65. For this period, USSR/Russia ranks first in weight and second in value, but Botswana is first in value and third in weight, just behind Australia. -
Graphene – Diamond Nanomaterials: a Status Quo Review
Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 29 July 2021 doi:10.20944/preprints202107.0647.v1 Article Graphene – diamond nanomaterials: a status quo review 1 Jana Vejpravová ,* 1 Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2, Czech Republic. * Correspondence: JV, [email protected] Abstract: Carbon nanomaterials with a different character of the chemical bond – graphene (sp2) and nanodiamond (sp3) are the building bricks for a new class of all-carbon hybrid nanomaterials, where the two different carbon networks with the sp3 and sp2 hybridization coexist, interact and even transform into one another. The unique electronic, mechanical, and chemical properties of the two border nanoallotropes of carbon ensure the immense application potential and versatility of these all-carbon graphene – diamond nanomaterials. The review gives an overview of the current state of the art of graphene – diamond nanomaterials, including their composites, heterojunctions, and other hybrids for sensing, electronic, energy storage, and other applications. Also, the graphene- to-diamond and diamond-to-graphene transformations at the nanoscale, essential for innovative fabrication, and stability and chemical reactivity assessment are discussed based on extensive theo- retical, computational, and experimental studies. Keywords: graphene; diamond; nanodiamond; diamane; graphene-diamond nanomaterials; all car- bon materials; electrochemistry; mechanochemistry; sensor; supercapacitor; -
X-Ray Topographic Investigation of Diamond Anvils for High Pressure Generation - Correlation Between Defects and Early Failure
X-ray topographic investigation of diamond anvils for high pressure generation - Correlation between defects and early failure Dewaele A. and Loubeyre P. CEA/DPTA, BP12, 91680 Bruyères le Châtel The diamond anvil cell technique revolutionized high pressure physics some 25 years ago. This device takes advantage of the unusual mechanical properties of the diamond. A metallic gasket with a hole in it to confine the sample is compressed between two diamond anvils. This device allows the generation of pressures that reach 300 GPa (3 millions times atmospheric pressure), pressure at which the diamond exhibits large elastic strain [1]. The pressure reached in diamond anvil cells is very often limited by the failure of a diamond anvil. In order to prevent this phenomenon, anvils are selected on the basis of their chemical purity, and their internal strains. However, the chemical purity does not guarantee the resistance of diamond anvils under high pressure operation. In particular, when the diamonds are used in contact with H2 or Helium samples, species which diffuse in diamond. Unfortunately, helium is known to be the best pressure transmitting medium, and is often loaded for that use in diamonds anvil cells [2]. A better understanding of early breakdown of diamond anvils and an a priori diagnostic of their resistance would thus constitute a major improvement for high pressure techniques. X-ray topography helps to establish this anvils quality diagnostic, because this method evidences intrinsic crystallographic defects of the anvils. These defects are likely to influence the mechanical properties of the anvil [3]. However, the liability of x-ray topography diagnostic had to be proven. -
OF SYNTHETIC DIAMONDS. Introduction
PI ^ AU9817130 IONOLUMINESCENCE (IL) OF SYNTHETIC DIAMONDS. A. A. Bettiol, K. W. Nugent, D. N. Jamieson and S. Prawer School of Physics, Microanalytical Research Centre, University of Melbourne, Parkville, 3052, AUSTRALIA. Introduction The optical properties of natural and synthetic diamonds have been extensively characterized in the past by absorption and luminescence. The use of such techniques as cathodoluminescence, photoluminescence, photoluminescence excitation and electron spin and paramagnetic resonance has resulted in the identification of many impurity and defect related optical centres in diamond [1-2]. Of the impurities found in diamond, nitrogen is by far the most abundant and hence responsible for most of the optical properties [3]. The development of diamond synthesis methods has resulted in the discovery of a number of a new optically active impurities and defects which are introduced during the growth process. These include Si, O, Ni and B [1-2]. In this study we identify a number of defect and impurity related centres in two commercially produced synthetic diamond samples by using the novel technique of ionoluminescence (IL) [4]. The first sample characterized is a Norton polycrystalline diamond detector. Signal produced in any charged particle detector is degraded if recombination of the electrons and holes occurs before the charge can be swept out by the electric field in the detector. In diamonds where the radiative recombination cross-section can be quite high, signal degradation can occur depending on the optical centres present and their lifetimes. Recombination centres with lifetimes much longer than the sweep out time will potentially saturate hence only cause a degradation of signal. -
DIAMOND Natural Colorless Type Iab Diamond with Silicon-Vacancy
Editors Thomas M. Moses | Shane F. McClure DIAMOND logical and spectroscopic features con- Natural Colorless Type IaB firmed the diamond’s natural origin, – Diamond with Silicon-Vacancy despite the occurrence of [Si-V] emis- Defect Center sions. No treatment was detected. Examination of this stone indicated The silicon-vacancy defect, or [Si-V]–, that the [Si-V]– defect can occur, albeit is one of the most important features rarely, in multiple types of natural dia- in identifying CVD synthetic dia- monds. Therefore, all properties should monds. It can be effectively detected be carefully examined in reaching a using laser photoluminescence tech- conclusion when [Si-V]– is present. nology to reveal sharp doublet emis- sions at 736.6 and 736.9 nm. This Carmen “Wai Kar” Lo defect is extremely rare in natural dia- monds (C.M. Breeding and W. Wang, “Occurrence of the Si-V defect center Figure 1. Emissions from the Screening of Small Yellow Melee for in natural colorless gem diamonds,” silicon-vacancy defect at 736.6 and Treatment and Synthetics Diamond and Related Materials, Vol. 736.9 nm were detected in this Diamond treatment and synthesis 17, No. 7–10, pp. 1335–1344) and has 0.40 ct type IaB natural diamond. have undergone significant develop- been detected in very few natural type ments in the last decade. During this IIa and IaAB diamonds over the past showed blue fluorescence with natural time, the trade has grown increasingly several years. diamond growth patterns. These gemo- concerned about the mixing of treated Recently, a 0.40 ct round brilliant diamond with D color and VS2 clarity (figure 1) was submitted to the Hong Figure 2. -
The World of Pink Diamonds and Identifying Them
GEMOLOGY GEMOLOGY as to what dealers can do to spot them using standard, geologists from Ashton Joint Venture found certain indicator The World of Pink Diamonds inexpensive instruments. The commercial signifcance of minerals (such as ilmenite, chromite, chrome diopside, the various types will also be touched on. and pyrope garnet) in stream-gravel concentrates which indicated the presence of diamond-bearing host rocks. and Identifying Them Impact of Auction Sales Lamproites are special ultrapotassic magnesium-rich In the late 1980s, the public perception surrounding fancy- mantle-derived volcanic rocks with low CaO, Al2O3, Na2O colored diamonds began to change when the 0.95-carat and high K2O. Leucite, glass, K-richterite, K-feldspar and Cr- By Branko Deljanin, Dr Adolf Peretti, ‘Hancock Red’ from Brazil was sold for almost $1 million per spinel are unique to lamproites and are not associated with and Matthias Alessandri carat at a Christie’s auction. This stone was studied by one kimberlites. The diamonds in lamproites are considered to be of the authors (Dr. Adolf Peretti) at that time. Since then, xenocrysts and derived from parts of the lithospheric mantle Dr. Peretti has documented the extreme impact this one that lies above the regions of lamproite genesis. Kimberlites sale has had on subsequent prices and the corresponding are also magmatic rocks but have a different composition recognition of fancy diamonds as a desirable asset class. The and could contain non-Argyle origin pink diamonds. demand for rare colors increased and the media began to play a more active role in showcasing new and previously Impact of Mining Activities unknown such stones. -
De Beers Natural Versus Synthetic Diamond Verification Instruments
DE BEERSNATURAL VERSUS By Christopher M.Welbourn, Martin Cooper, and Paul M,Spear Twoinstruments have been developed at he subject of cuttable-quality synthetic diamonds De Beers DTC Research Centre, has been receiving much attention in the gem trade Maidenhead, to distinguish synthetic dia- recently. Yellow to yellow-brown synthetic diamonds grown monds from natural diamonds. The in Russia have been offered for sde at a number of recent DiainondSureTMenables the rapid exami- gem and jewelry trade shows (Shor and Weldon, 1996; nation of large numbers of polished dia- monds, both loose and set in jewehy. Reinitz, 1996; Johnson and Koivula, 1996))and a small num- Automatically and with high sensitivity, ber of synthetic diamonds have been submitted to gem grad- this instrument detects the presence of the ing laboratories for identification reports (Fryer, 1987; 415 nm optical absorption line, which is Reinitz, 1996; Moses et al., 1993a and b; Emms, 1994; found in the vast majority of natural dia- Kammerling et al., 1993, 1995; Kammerling and McClure, monds but not in synthetic diamonds. 1995). Particular concern was expressed following recent Those stones in which this line is detected announcements of the production and planned marketing of are "passed" by the instrument, and those near-colorless synthetic diamonds (Koivula et al., 1994; in which it is not detected are "referredfor "Upfront," 1995). further tests." The DiamondViewTRfpro- Synthetic diamonds of cuttable size and quality, and the duces a fluorescence image of the surface of technology to produce them, are not new. In 1971, researchers a polished diamond, from which the growth structure of the stone may be deter- at the General Electric Company published the results of mined. -
Large Man-Made Diamond Single Crystals: Manufacture, Properties and Application
Large man-made diamond single crystals: manufacture, properties and application Dr. Sergey A.Terentjev , the head of Department of Single Crystal Growth. Technological Institute for Superhard and Novel Carbon Materials ( ТISN СМ ) E-mail: Diamond is a material possessing a unique complex of physical and chemical properties which potentially allow using it, besides traditional application in the processing industry, in Hi- Tech branches also. Such use of diamond restrains by insufficient quantity of natural perfect raw material of so-called "device" quality. Single crystals of diamond grown up in laboratory conditions differ from natural, first of all, in high reproducibility of physical properties (impurities level, an optical transparency, heat conductivity, specific electric resistance, etc.). Creation of technologies for cultivation a high purity «nitrogen free» (IIa type) and semi- conductor (IIb type) large diamond single crystals, which are extremely rare among natural diamonds and very expensive, is of the great interest and simultaneously of the greatest difficulty. Technologies for manufacture of both IIa and IIb diamond single crystals 0.5 to 5.0 carat in weight (characteristic size 3÷8 mm) from solvent/catalyst melt of transitive metals at high static pressures and temperatures (based on a temperature gradient growth technique) have been developed by Dr. Terentiev’s research team some years ago and successfully introduced in industrial department of ТISN СМ . Man-made IIa type single crystals are characterized by an optical transparency in a less than 25 µm wave lengths region and have fundamental absorption edge at 225 nanometers. Their thermal conductivity reaches 2000 Wt/m• К. Nitrogen concentration (a basic impurity element) level does not exceed 2 рр m (usually less than 1 рр m). -
Method of Making Synthetic Diamond Film
Europaisches Patentamt European Patent Office © Publication number: 0 597 445 A2 Office europeen des brevets EUROPEAN PATENT APPLICATION © Application number: 93118150.7 int. Ci.5; C23C 16/00, C23C 16/26 @ Date of filing: 09.11.93 ® Priority: 10.11.92 US 973994 32 Cornell Street Arlington, MA 02174(US) @ Date of publication of application: Inventor: Frey, Robert M. 18.05.94 Bulletin 94/20 77 Santa Isabel Nr.2-14 Laguna Vista, Texas 78578(US) © Designated Contracting States: DE FR GB 0 Representative: Diehl, Hermann, Dr. © Applicant: NORTON COMPANY Dipl.-Phys. et al 1 New Bond Street DIEHL, GLASER, HILTL & PARTNER Worcester, MA 01615-0008(US) Patentanwalte Fluggenstrasse 13 @ Inventor: Simpson, Matthew D-80639 Munchen (DE) © Method of making synthetic diamond film. © The invention describes a method for making a free-standing synthetic diamond film of desired thickness, comprising the steps of: no SELECT TARGET providing a substrate; X THICKNESS OF DIAMOND selecting a target thickness of diamond to be TO BE PRODUCED produced, said target thickness being in the range 200 urn to 1000 urn; finishing a surface of the substrate to a rough- 1 20 finish surface of ness, RA that is a function of the target thickness, substrate to prescribed said roughness being determined from ra Roughness 0.38t/600 urn ^ Ra = 0.50 urn 200 urn < t ^ 600 urn 0.38 urn ^ Ra = 0.50 urn 600 urn < t < 1000 1 30, urn DEPOSIT INTERLAYER where t is the target thickness; said the inter- CM depositing an interlayer on substrate, layer having a thickness in the range 1 to 20 urn; depositing synthetic diamond on said interlayer, by I40. -
CVD Synthetic Diamond Identifed in the GIT-GTL
Lab Update CVD Synthetic Diamond Identified in the GIT-GTL Supparat Promwongnan, Thanong Leelawatanasuk, Thanapong Lhuaamporn of the GIT-Gem Testing Laboratory Keywords: CVD, HPHT, Synthetic, Diamond, Color enhancement, spectroscopy, treatment Figure 1. A total of 27 faceted slightly tinted yellow CVD-grown synthetic diamonds were sent to the GIT-GTL for diamond grading reports, as of natural origin. The samples selected have an average weight of 0.40 ct. Photo by S. Promwongnan. Introduction – infrared absorption spectra showing the of these samples ranged from VVS2 to SI1. During the past decade, a large number of presence of trace amounts of nitrogen The colour grade of the diamonds is slightly gem-quality synthetic diamonds have entered defect at 1344 cm−1; tinted yellow. All samples were further the diamond industry with a wide range of – photoluminescence spectra showing strong tested with the D-Screen which is a portable quality in terms of size, colour and clarity. emissions from N-V centres and distinct diamond screening device. The internal Consequently, there have been reports of cases doublet peaks at 736.6 nm and 736.9 nm, features were observed under a gemmologi- of fraud in the diamond business, for example: related to the Si-related defect; cal microscope. Furthermore between crossed intentionally selling synthetic diamond as – the lamellar growth patterns seen with the polarizers, strain patterns and interference natural diamond or intentionally mixing a DiamondView imaging system. colours could be seen. All photomicrographs were collected by a Canon EOS 7D Photo- natural diamond parcel with a synthetic one. All these characteristics can be used to sepa- microscope.