Winter 2003 Gems & Gemology
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The Dependence of the Sio Bond Length on Structural Parameters in Coesite, the Silica Polymorphs, and the Clathrasils
American Mineralogist, Volume 75, pages 748-754, 1990 The dependence of the SiO bond length on structural parameters in coesite, the silica polymorphs, and the clathrasils M. B. BOISEN, JR. Department of Mathematics, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, U.S.A. G. V. GIBBS, R. T. DOWNS Department of Geological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, U.S.A. PHILIPPE D' ARCO Laboratoire de Geologie, Ecole Normale Superieure, 75230 Paris Cedex OS, France ABSTRACT Stepwise multiple regression analyses of the apparent R(SiO) bond lengths were com- pleted for coesite and for the silica polymorphs together with the clathrasils as a function of the variables};(O), P (pressure), f,(Si), B(O), and B(Si). The analysis of 94 bond-length data recorded for coesite at a variety of pressures and temperatures indicates that all five of these variables make a significant contribution to the regression sum of squares with an R2 value of 0.84. A similar analysis of 245 R(SiO) data recorded for silica polymorphs and clathrasils indicate that only three of the variables (B(O), };(O), and P) make a signif- icant contribution to the regression with an R2 value of 0.90. The distribution of B(O) shows a wide range of values from 0.25 to 10.0 A2 with nearly 80% of the observations clustered between 0.25 and 3.0 A2 and the remaining values spread uniformly between 4.5 and 10.0 A2. A regression analysis carried out for these two populations separately indicates, for the data set with B(O) values less than three, that };(O) B(O), P, and };(Si) are all significant with an R2 value of 0.62. -
Crystalline Silica, Cristobalite (CAS No
Crystalline Silica, Quartz (CAS No. 14808-60-7) Crystalline Silica, Cristobalite (CAS No. 14464-46-1) Crystalline Silica, Tridymite (CAS No. 15468-32-3) Diatomaceous earth (CAS No. 61790-53-2) This dossier on crystalline silica, quartz, cristobalite and tridymite and diatomaceous earth presents the most critical studies pertinent to the risk assessment of these substances in their use in drilling muds and cement additives. This dossier does not represent an exhaustive or critical review of all available data. The majority of information presented in this dossier was obtained from the ECHA database that provides information on chemicals that have been registered under the EU REACH (ECHA). Where possible, study quality was evaluated using the Klimisch scoring system (Klimisch et al., 1997). For the purpose of this dossier, crystalline silica, quartz (CAS No. 14808-60-7) has been reviewed as representative of crystalline silica cristobalite and tridymite. Crystalline silica, quartz is also considered representative of diatomaceous earth, as they both consist mainly of silicon dioxide. Screening Assessment Conclusion – Crystalline silica, quartz, cristobalite and tridymite and diatomaceous earth are classified as tier 1 chemicals and require a hazard assessment only. 1 BACKGROUND Crystalline silica is a common mineral found in the earth's crust. Materials like sand, stone, concrete and mortar contain crystalline silica. It is also used to make products such as glass, pottery, ceramics, bricks and artificial stone. Silica, in the form of sand, is used as the main ingredient in sand casting for the manufacture of metallic components in engineering and other applications. The high melting point of silica enables it to be used in such applications. -
Pezzottaite from Ambatovita, Madagascar: a New Gem Mineral
PEZZOTTAITE FROM AMBATOVITA, MADAGASCAR: A NEW GEM MINERAL Brendan M. Laurs, William B. (Skip) Simmons, George R. Rossman, Elizabeth P. Quinn, Shane F. McClure, Adi Peretti, Thomas Armbruster, Frank C. Hawthorne, Alexander U. Falster, Detlef Günther, Mark A. Cooper, and Bernard Grobéty Pezzottaite, ideally Cs(Be2Li)Al2Si6O18, is a new gem mineral that is the Cs,Li–rich member of the beryl group. It was discovered in November 2002 in a granitic pegmatite near Ambatovita in cen- tral Madagascar. Only a few dozen kilograms of gem rough were mined, and the deposit appears nearly exhausted. The limited number of transparent faceted stones and cat’s-eye cabochons that have been cut usually show a deep purplish pink color. Pezzottaite is distinguished from beryl by its higher refractive indices (typically no=1.615–1.619 and ne=1.607–1.610) and specific gravity values (typically 3.09–3.11). In addition, the new mineral’s infrared and Raman spectra, as well as its X-ray diffraction pattern, are distinctive, while the visible spectrum recorded with the spec- trophotometer is similar to that of morganite. The color is probably caused by radiation-induced color centers involving Mn3+. eginning with the 2003 Tucson gem shows, (Be3Sc2Si6O18; Armbruster et al., 1995), and stoppaniite cesium-rich “beryl” from Ambatovita, (Be3Fe2Si6O18; Ferraris et al., 1998; Della Ventura et Madagascar, created excitement among gem al., 2000). Pezzottaite, which is rhombohedral, is Bcollectors and connoisseurs due to its deep purplish not a Cs-rich beryl but rather a new mineral species pink color (figure 1) and the attractive chatoyancy that is closely related to beryl. -
Thermal Behavior of Afghanite, an ABABACAC Member of the Cancrinite Group
American Mineralogist, Volume 97, pages 630–640, 2012 Thermal behavior of afghanite, an ABABACAC member of the cancrinite group PAOLO BALLIRANO1,2,* AND FERDINANDO BOSI1,3 1Dipartimento di Scienze della Terra, Sapienza Università di Roma, P.le Aldo Moro 5, I-00185, Roma, Italy 2CNR-IGAG, Istituto di Geologia Ambientale e Geoingegneria, Sede di Roma, Via Bolognola 7, I-00138 Roma, Italy 3CNR-IGG Istituto di Geoscienze e Georisorse, Sede di Roma, P.le A. Moro, 5, I-00185 Roma, Italy ABSTRACT Thermal behavior of afghanite, (Na15K5Ca11)Σ31[Si24Al24O96](SO4)6Cl6, P31c, a = 12.7961(7) Å, c = 21.4094(13) Å, an eight-layer member of the cancrinite group, has been investigated by combined electron microprobe analysis, X-ray single-crystal diffraction, and high-temperature X-ray powder diffraction. Non-ambient X-ray powder diffraction data were collected in the 323–1223 K thermal range on a specimen from Case Collina, Latium, Italy. Structural refinement and site assignment based on the bond-valence analysis, performed on room-temperature single-crystal X-ray diffraction data, provided more accurate site allocation of cations than the available model in the literature. The results show that the cancrinite cages alternating with the liottite cages are more compressed along the c-axis than the remaining ones. As a result the chlorine atom, located at the center of the cages, is driven off-axis to release the steric strain due to the cage compression. Thermal expansion shows a discontinuity at 448 K for both a and c unit-cell parameters, a feature previously reported for other cancrinite-like minerals. -
The Red Emerald
The Red Emerald Black Album Words by Seth William Rozendaal Photos by David Rozendaal This work is for the enjoyment of gemstone aficionados around the world and throughout time, and dedicated to the divine muse who inspires everything. This book celebrates the Red Emerald’s public debut at the 2017 Tucson Gem and Mineral Show. Graphics taken from the Mineralogical Record Volume 47 Number 1: Colombian Emeralds where noted. The two photos of the Heart matrix specimen on the top of the page in Section VI were taken by Wayne Schrimp. Seth Rozendaal is responsible for the landscape photo in Section II, the beveled heart in Section VI and Office Suite Graphics. The Suite Treasure necklace photo in Section XIII was taken at the Brent Isenberger Studio. Cover and all other interior photos in this album were taken by David Rozendaal. Without his tireless dedication, this publication would not have been possible. For additional information, please contact: Seth William Rozendaal (515) 868-7207 [email protected] Index I - Red Beryl IS Red Emerald II - Formation III - Matrix Specimens IV - Wafers V - Prisms VI - Twins VII - Clusters VIII - Bixbyite Combinations IX - Topaz Combinations X - Hourglass Patterning XI - The Scarlet Spectrum XII - Facet-Grade Red Emerald XIII - The Red Emerald Suite Treasure I ~ Red Beryl IS Red Emerald The human infatuation with Emeralds runs so deep, and our desire for them traces so far back… It's one of the only gemstones found in rank-signifying Neolithic headdresses. Yeah, you heard me: Caveman Crowns. Aja Raden - Author, Historian and Scientist Diamonds may be forever, but only Emeralds are eternal; our appreciation of Emeralds stretches from the beginning of human civilization to the very end. -
Washington State Minerals Checklist
Division of Geology and Earth Resources MS 47007; Olympia, WA 98504-7007 Washington State 360-902-1450; 360-902-1785 fax E-mail: [email protected] Website: http://www.dnr.wa.gov/geology Minerals Checklist Note: Mineral names in parentheses are the preferred species names. Compiled by Raymond Lasmanis o Acanthite o Arsenopalladinite o Bustamite o Clinohumite o Enstatite o Harmotome o Actinolite o Arsenopyrite o Bytownite o Clinoptilolite o Epidesmine (Stilbite) o Hastingsite o Adularia o Arsenosulvanite (Plagioclase) o Clinozoisite o Epidote o Hausmannite (Orthoclase) o Arsenpolybasite o Cairngorm (Quartz) o Cobaltite o Epistilbite o Hedenbergite o Aegirine o Astrophyllite o Calamine o Cochromite o Epsomite o Hedleyite o Aenigmatite o Atacamite (Hemimorphite) o Coffinite o Erionite o Hematite o Aeschynite o Atokite o Calaverite o Columbite o Erythrite o Hemimorphite o Agardite-Y o Augite o Calciohilairite (Ferrocolumbite) o Euchroite o Hercynite o Agate (Quartz) o Aurostibite o Calcite, see also o Conichalcite o Euxenite o Hessite o Aguilarite o Austinite Manganocalcite o Connellite o Euxenite-Y o Heulandite o Aktashite o Onyx o Copiapite o o Autunite o Fairchildite Hexahydrite o Alabandite o Caledonite o Copper o o Awaruite o Famatinite Hibschite o Albite o Cancrinite o Copper-zinc o o Axinite group o Fayalite Hillebrandite o Algodonite o Carnelian (Quartz) o Coquandite o o Azurite o Feldspar group Hisingerite o Allanite o Cassiterite o Cordierite o o Barite o Ferberite Hongshiite o Allanite-Ce o Catapleiite o Corrensite o o Bastnäsite -
Mineral Processing
Mineral Processing Foundations of theory and practice of minerallurgy 1st English edition JAN DRZYMALA, C. Eng., Ph.D., D.Sc. Member of the Polish Mineral Processing Society Wroclaw University of Technology 2007 Translation: J. Drzymala, A. Swatek Reviewer: A. Luszczkiewicz Published as supplied by the author ©Copyright by Jan Drzymala, Wroclaw 2007 Computer typesetting: Danuta Szyszka Cover design: Danuta Szyszka Cover photo: Sebastian Bożek Oficyna Wydawnicza Politechniki Wrocławskiej Wybrzeze Wyspianskiego 27 50-370 Wroclaw Any part of this publication can be used in any form by any means provided that the usage is acknowledged by the citation: Drzymala, J., Mineral Processing, Foundations of theory and practice of minerallurgy, Oficyna Wydawnicza PWr., 2007, www.ig.pwr.wroc.pl/minproc ISBN 978-83-7493-362-9 Contents Introduction ....................................................................................................................9 Part I Introduction to mineral processing .....................................................................13 1. From the Big Bang to mineral processing................................................................14 1.1. The formation of matter ...................................................................................14 1.2. Elementary particles.........................................................................................16 1.3. Molecules .........................................................................................................18 1.4. Solids................................................................................................................19 -
Minnesota's Mineral Resources
CHAPTER • 9 Minnesota's Mineral Resources IN MINNESOTA the production of iron ore is far more valuable economically than the total of all other mineral products, but im portant industries are based on Minnesota's other geological forma tions as well. Architectural, monumental, and structural stone are produced from granite, limestone, dolomite, and other Minnesota rocks. Gravel and sand are excavated and processed, and clay is used for many ceramic products. :Manganese in important amounts occurs in the iron ores of the Cuyuna district. Finally, although they are often not thought of as mineral products, two of our most im portant mineral resources are water and soil. The iron ores and mining operations of the Mesabi, Vermilion, and Cuyuna iron-bearing districts and of the southeastern lYlinnesota counties will be discussed in detail in later chapters, but a few sta tistics on Minnesota's iron ore industry may remind us how impor tant this geological heritage is. The following is an estimate of Min nesota's iron ore reserves, made on lYlay 1, 1961: Gross Tons Mesabi Range 500,799,179 Vermilion Range 9,755,974 Cuyuna Range 36,530,000 Fillmore County 'il,860,337 Total iron ore 549,945,490 172 MI NESOTA'S MINERAL RESOURCES The total production of iron ore in Minne ota to January 1, 1962, was 2,529,737,553 tons. Total taxes paid on iron ore to January 1, 1961 , were approximately $1,257,448,400, a very important source of funds for the state government. Slightly over 60 per cent of the total iron ore produced in the United States has come from l\1inne- ota. -
Marinellite, a New Feldspathoid of the Cancrinite-Sodalite Group
Eur. J. Mineral. 2003, 15, 1019–1027 Marinellite, a new feldspathoid of the cancrinite-sodalite group ELENA BONACCORSI* and PAOLO ORLANDI Dipartimento di Scienze della Terra, Universita` di Pisa, Via S. Maria 53, I-56126 Pisa, Italy * Corresponding author, e-mail: [email protected] Abstract: Marinellite, [(Na,K)42Ca6](Si36Al36O144)(SO4)8Cl2·6H2O, cell parameters a = 12.880(2) Å, c = 31.761(6) Å, is a new feldspathoid belonging to the cancrinite-sodalite group. The crystal structure of a twinned crystal was preliminary refined in space group P31c, but space group P62c could also be possible. It was found near Sacrofano, Latium, Italy, associated with giuseppettite, sanidine, nepheline, haüyne, biotite, and kalsilite. It is anhedral, transparent, colourless with vitreous lustre, white streak and Mohs’ hardness of 5.5. The mineral does not fluoresce, is brittle, has conchoidal fracture, and presents poor cleavage on {001}. Dmeas is 3 3 2.405(5) g/cm , Dcalc is 2.40 g/cm . Optically, marinellite is uniaxial positive, non-pleochroic, = 1.495(1), = 1.497(1). The strongest five reflections in the X-ray powder diffraction pattern are [d in Å (I) (hkl)]: 3.725 (100) (214), 3.513 (80) (215), 4.20 (42) (210), 3.089 (40) (217), 2.150 (40) (330). The electron microprobe analysis gives K2O 7.94, Na2O 14.95, CaO 5.14, Al2O3 27.80, SiO2 32.73, SO3 9.84, Cl 0.87, (H2O 0.93), sum 100.20 wt %, less O = Cl 0.20, (total 100.00 wt %); H2O calculated by difference. The corresponding empirical formula, based on 72 (Si + Al), is (Na31.86K11.13Ca6.06) =49.05(Si35.98Al36.02)S=72O144.60(SO4)8.12Cl1.62·3.41H2O. -
Scandiobabingtonite, a New Mineral from the Baveno Pegmatite
American Mineralogist, Volume 83, pages 1330-1334, 1998 Scandiobabingtonite,a new mineral from the Bavenopegmatite, Piedmont, Italy Ploro ORl.tNnIrr'* Ma,nco PasERorr and GrovlNNa Vn,zzllrNr2 rDipartimento di Scienzedella Terra, Universitd di Pisa, Via S. Maria 53,1-56126 Pisa, Italy '?Dipartimento di Scienzedella Terra, Universitd di Modena, Via S Eufemia 19, I-41 100 Modena, Italy Ansrntcr Scandiobabingtonite,ideally Ca,(Fe,*,Mn)ScSi,O,o(OH) is the scandium analogue of babingtonite; it was found in a pegmatitic cavity of the Baveno granite associatedwith orthoclase, albite, muscovite, stilbite, and fluorite. Its optics are biaxial (+) with 2V : : ^v: 64(2)",ct 1.686(2),P: 1.694(3), 1.709(2).D-"." : 3.24(5)slcm3, D.",.:3.24 sl cm3, and Z : 2. Scandiobabingtoniteis colorless or pale gray-green, transparent,with vitreous luster. It occurs as submillimeter sized, short, tabular crystals, slightly elongated on [001],and characterizedby the associationof forms {010}, {001}, {110}, {110}, and {101}. It occurs also as a thin rim encrustingsmall crystals of babingtonite.The strongest lines in the X-ray powder pauern are at2.969 (S), 2.895 (S), 3.14 (mS), and 2.755 (mS) 4. fn" mineralis triclinic, ipu.. g.oup PT, with a : 7.536(2),b : 1L734(2),c : 6.t48(Z) A, : 91.10(2), : 93.86(2), : lO+.S:(2)'. Scandiobabingtoniteis isostructural " B r with babingtonite, with Sc replacing Fe3* in sixfold coordination, but no substitution of Fer* by Sc takes place. Due to the lack of a suitably large crystal of the new species, such a replacementhas been confirmed by refining the crystal structure of a Sc-rich babingtonite (final R : O.O47)using single-crystal X-ray diffraction (XRD) data. -
26 May 2021 Aperto
AperTO - Archivio Istituzionale Open Access dell'Università di Torino The crystal structure of sacrofanite, the 74 Å phase of the cancrinite–sodalite supergroup This is the author's manuscript Original Citation: Availability: This version is available http://hdl.handle.net/2318/90838 since Published version: DOI:10.1016/j.micromeso.2011.06.033 Terms of use: Open Access Anyone can freely access the full text of works made available as "Open Access". Works made available under a Creative Commons license can be used according to the terms and conditions of said license. Use of all other works requires consent of the right holder (author or publisher) if not exempted from copyright protection by the applicable law. (Article begins on next page) 05 October 2021 This Accepted Author Manuscript (AAM) is copyrighted and published by Elsevier. It is posted here by agreement between Elsevier and the University of Turin. Changes resulting from the publishing process - such as editing, corrections, structural formatting, and other quality control mechanisms - may not be reflected in this version of the text. The definitive version of the text was subsequently published in MICROPOROUS AND MESOPOROUS MATERIALS, 147, 2012, 10.1016/j.micromeso.2011.06.033. You may download, copy and otherwise use the AAM for non-commercial purposes provided that your license is limited by the following restrictions: (1) You may use this AAM for non-commercial purposes only under the terms of the CC-BY-NC-ND license. (2) The integrity of the work and identification of the author, copyright owner, and publisher must be preserved in any copy. -
INCLUSIONS in AQUAMARINE from AMBATOFOTSIKELY, MADAGASCAR Fabrice Danet, Marie Schoor, Jean-Claude Boulliard, Daniel R
NEW Danet G&G Fall 2012_Layout 1 9/27/12 11:31 AM Page 205 RAPID COMMUNICATIONS INCLUSIONS IN AQUAMARINE FROM AMBATOFOTSIKELY, MADAGASCAR Fabrice Danet, Marie Schoor, Jean-Claude Boulliard, Daniel R. Neuville, Olivier Beyssac, and Vincent Bourgoin grams of translucent to transparent beryl were pro- duced, as well as several tonnes of opaque material In January 2012, aquamarine crystals containing for industrial use. While only a very small percentage interesting inclusions were extracted from the Am- was suitable for faceting, several hundred aqua- batofotsikely area northwest of Antsirabe, Mada- marines in the 1–35 ct range have been cut. In April gascar. These specimens displayed various types 2012, one of the authors (FD) traveled to the locality of eye-visible and microscopic inclusions, and and obtained representative samples. some had an unusual form. Raman microspec- troscopy identified reddish brown plate lets as Location and Geologic Setting. The workings are lo- hematite, while ilmenite was found as black cated less than 1 km north of Ambatofotsikely (a village platelets, black needles, and distinctive dark gray now locally known as Ambatofotsy Carole), 22 km dendrites. Similar inclusions are known in beryl north-northwest of Ankazomiriotra, and 74 km north- from Brazil, India, Mozambique, and Sri Lanka. west of Antsirabe. The deposit is centered at coordinates 19°27.662¢S, 46°27.450¢E, at an elevation of 1,010 m. The site is accessed by a paved road (RN 34) from ining activity near the central Malagasy village Antsirabe to a point 16 km west of Ankazomiriotra. of Ambatofotsikely was first documented nearly From there, a trail extends 15 km to Ambatofotsikely.