Gemstones in Metal Clay
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Preliminary Investigation of Purple Garnet from a New Deposit in Mozambique
GIT GEMSTONE UPDATE Preliminary Investigation of Purple Garnet from a New Deposit in Mozambique By GIT-Gem testing laboratory 11 May 2016 Introduction In March 2016, a group of Thai gem dealer led by Mr. Pichit Nilprapaporn paid a visit to the GIT and informed us about a new garnet deposit in Mozambique, that was discovered near the western border with Zimbabwe. They also displayed a large parcel of rough and a few cut stones claimed to be the material found in this new deposit (Figure 1). According to the stone’s owner, these garnet specimens were unearthed from an unconsolidated sediment layer, just a few meters below ground surface. This brief report is our preliminary investigation on the interesting vivid purple garnet from the new deposit in Mozambique. Figure 1: Mr. Pichit Nilprapaporn (center), the stone’s owner, showing a large parcel of purple gar- net roughs claimed to be from a new deposit in Mozambique to the GIT director (left). The Gem and Jewelry Institute of Thailand (Public Organization) 140, 140/1-3, 140/5 ITF-Tower Building. 1st - 4th and 6th Floor,Silom Road, Suriyawong, Bangrak, Bangkok 10500 Thailand Tel: +66 2634 4999 Fax: +66 2634 4970; Web: http://www.git.or.th; E-mail: [email protected] 11 May, 2016 Preliminary Investigation of Purple Garnet from a New Deposit in Mozambique 2 Samples and Testing Procedure The stone’s owners donated some specimens (one 6.10 ct oval-facetted stone and 13 rough samples weighing from 3.83 to 9.43 cts) to the GIT Gem Testing Laboratory for studying. -
Garnet Cigdem Lule, Phd., FGA, GG (GIA)
Market Trends Garnet Cigdem Lule, PhD., FGA, GG (GIA) he Tucson 2015 Gem Show demonstrated that there are considerably more options than just the big three (Truby, sapphire and emerald) for buyers seeking fine quality gemstones. The availability of bigger and higher Figure 1. Tsavorite garnet quality garnets in a range of colors, including color- 6.00cts. Courtesy change was notable. Gem professionals know only too of Mayer & Watt, well that, although red garnets are common, it is no easy photo by Geoffrey task to locate a fine quality rhodolite or spessartine of Watt. 10cts or larger. Dealers with fine red garnets in these sizes reported that the issue isn’t with demand; it is with trying to replace the stone after it’s sold. Similarly, in the Rhodolite 3 carats Commercial Good Fine Extra Fine 2005 4-18 18-35 35-50 50-60 2010 4-18 18-35 35-60 60-70 2015 4-22 30-50 60-95 120-140 Tsavorite 3 carats Commercial Good Fine Extra Fine 2005 225 & up 675-1,000 1,000-1,300 1,300-2,000 2010 240 & up 800-1,400 1,400-1,900 1,900-2,850 2015 240-450 1,150-1,725 2,000-2,400 3,000-3,500 Note. Current price tables have 10 categories but for representation here, categories are combined to show only the four main quality grades. orange category, fine grade mandarin garnets are also their own merit. The per carat price, one of the highest once again achieving greater popularity, and prices are for any garnet, is proof enough of that. -
History of the Gems Found in North Carolina
'I F \1111111:1111'11\\' .'·f .1 (;,,..r'j, >'IJ·I .. , I· I,.t 'I I ,~ /'t\1 t(l~'F-" (-- , ,'. ,',' I.~ .()U~lr., , l' _,\ .... +'" .... (.Jf'J.:"') i ~ j' ~" . ..... ," - (" , .. - "'r' .. BARVARD UNIVERSITY LIBRARY OF THE MINERALOGICAL LABORATORY UNIVERSITY MUSEUM Transferred to CABOT SCIENCE LIBRARY June 2005 I ~/~_ . Digitized by Google • HISTORY OF THE GEMS FOUND IN NORTH CAROLINA H GIIORGB lI'RBDBRICE KUNZ, PH.D. Digitized by Google NORTH CAROLINA GEOLOGICAL lAND ECONOMIC SURVEY JOSEPH HYDE PRATT, STATE GEOLOGIST BULLETIN NO. 12 HISTORY OF THE GEMS FOUND IN NORTH CAROLINA BY GEORGE FREDERICK KUNZ, PH.D. RALEIGH E. M. UZZELL .t Co., PUBLIO PaINTEB8 AND BINDD8 1907 Digitized byGQogle BOARD GovJm.NOB R. B. GLDN," of/lClo Olaoirm.cm •.....•••••••••••.• Raleigh. BuBy FBD:8. • • • . • • • • . .. • • • • . • • • .. • • .. • •••.••• Wlnlton·Salem. s.wrrr. ... ....... , .... " ...... • ... Asheville. HUGH MAoR.&l: ... ..................................•....... Wllmlngton. lI'Iu.NK WOOD .•.................................•.......... llIdenton. GeologiBt. '" .... .. .. Chapel .' Digitized LETTER OF TRANSMITTAL CHAPEL HILL, N. C., November 15, 1906. To Bil E:Z;C6lZency, HON. R. B. GLENN, G01J6mof' of N orl.h Ocwolina. B1,r.-I have the honor to submit for publication as Bulletin No. 12 of the Geological and Economic Survey, the report of Dr. George Frederick Kunz on the History of the Gems found in North Carolina. Yours obediently, JOSEPH HYDE PUTT, 8tate Geologist. Digitized by Google CONTENTS P.GJC PBD.CJC "............................................................. Ill: Ilft'aODUCTIOK .......................... .. • .. .. .. • • • .. • • • .. • • .. .. • .. • • %1 ClU.Pl'EB I.-HISTOBIc.&L 8KJCTCB: 01' GJCK xmmG m NOBTH C.aoLIK.. • • • 1 II.-DL\J(OKDB • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 5 III.-COBUNDl1J( GJCK8 ••••••••••••••••••••••••••••••••••••••• 10 IV.-GBK HINEB.&L8 01' THJC ne-.'l'1'1'JC Dm.. • • . • • • • . • • • • . • • 25 The feldspars •....•...•...•••••••••••••••••..••••••• J7 Orthoclase . -
Mineral Collecting Sites in North Carolina by W
.'.' .., Mineral Collecting Sites in North Carolina By W. F. Wilson and B. J. McKenzie RUTILE GUMMITE IN GARNET RUBY CORUNDUM GOLD TORBERNITE GARNET IN MICA ANATASE RUTILE AJTUNITE AND TORBERNITE THULITE AND PYRITE MONAZITE EMERALD CUPRITE SMOKY QUARTZ ZIRCON TORBERNITE ~/ UBRAR'l USE ONLV ,~O NOT REMOVE. fROM LIBRARY N. C. GEOLOGICAL SUHVEY Information Circular 24 Mineral Collecting Sites in North Carolina By W. F. Wilson and B. J. McKenzie Raleigh 1978 Second Printing 1980. Additional copies of this publication may be obtained from: North CarOlina Department of Natural Resources and Community Development Geological Survey Section P. O. Box 27687 ~ Raleigh. N. C. 27611 1823 --~- GEOLOGICAL SURVEY SECTION The Geological Survey Section shall, by law"...make such exami nation, survey, and mapping of the geology, mineralogy, and topo graphy of the state, including their industrial and economic utilization as it may consider necessary." In carrying out its duties under this law, the section promotes the wise conservation and use of mineral resources by industry, commerce, agriculture, and other governmental agencies for the general welfare of the citizens of North Carolina. The Section conducts a number of basic and applied research projects in environmental resource planning, mineral resource explora tion, mineral statistics, and systematic geologic mapping. Services constitute a major portion ofthe Sections's activities and include identi fying rock and mineral samples submitted by the citizens of the state and providing consulting services and specially prepared reports to other agencies that require geological information. The Geological Survey Section publishes results of research in a series of Bulletins, Economic Papers, Information Circulars, Educa tional Series, Geologic Maps, and Special Publications. -
Gem Wealth of Tanzania GEMS & GEMOLOGY Summer 1992 Fipe 1
By Dona M.Dirlarn, Elise B. Misiorowski, Rosemaiy Tozer, Karen B. Stark, and Allen M.Bassett The East African nation of Tanzania has he United Republic of Tanzania, the largest of the East great gem wealth. First known by Western- 1African countries, is composed of mainland Tanzania and ers for its diamonds, Tanzania emerged in the island of Zanzibar. 1t is regarded by many as the birthplace the 1960s as a producer of a great variety of of the earliest ancestors of Homo sapiens. To the gem indus- other gems such as tanzanite, ruby, fancy- try, however, Tanzania is one of the most promising fron- colored sapphire, garnet, and tourmaline; to date, more than 50 gem species and vari- tiers, with 50 gem species and varieties identified, to date, eties have been produced. As the 1990s from more than 200 occurrences. begin, De Beers has reinstated diamond "Modem" mining started in the gold fields of Tanzania in exploration in Tanzania, new gem materials the late 1890s (Ngunangwa, 19821, but modem diamond min- such as transparent green zoisite have ing did not start until 1925, and nearly all mining of colored appeared on the market, and there is stones has taken place since 1950. Even so, only a few of the increasing interest in Tanzania's lesser- gem materials identified have been exploited to any significant known gems such as scapolite, spinel, and extent: diamond, ruby, sapphire, purplish blue zoisite (tan- zircon. This overview describes the main zanite; figure l),and green grossular [tsavorite)and other gar- gems and gem resources of Tanzania, and nets. -
Reflective Index Reference Chart
REFLECTIVE INDEX REFERENCE CHART FOR PRESIDIUM DUO TESTER (PDT) Reflective Index Refractive Reflective Index Refractive Reflective Index Refractive Gemstone on PDT/PRM Index Gemstone on PDT/PRM Index Gemstone on PDT/PRM Index Fluorite 16 - 18 1.434 - 1.434 Emerald 26 - 29 1.580 - 1.580 Corundum 34 - 43 1.762 - 1.770 Opal 17 - 19 1.450 - 1.450 Verdite 26 - 29 1.580 - 1.580 Idocrase 35 - 39 1.713 - 1.718 ? Glass 17 - 54 1.440 - 1.900 Brazilianite 27 - 32 1.602 - 1.621 Spinel 36 - 39 1.718 - 1.718 How does your Presidium tester Plastic 18 - 38 1.460 - 1.700 Rhodochrosite 27 - 48 1.597 - 1.817 TL Grossularite Garnet 36 - 40 1.720 - 1.720 Sodalite 19 - 21 1.483 - 1.483 Actinolite 28 - 33 1.614 - 1.642 Kyanite 36 - 41 1.716 - 1.731 work to get R.I. values? Lapis-lazuli 20 - 23 1.500 - 1.500 Nephrite 28 - 33 1.606 - 1.632 Rhodonite 37 - 41 1.730 - 1.740 Reflective indices developed by Presidium can Moldavite 20 - 23 1.500 - 1.500 Turquoise 28 - 34 1.610 - 1.650 TP Grossularite Garnet (Hessonite) 37 - 41 1.740 - 1.740 be matched in this table to the corresponding Obsidian 20 - 23 1.500 - 1.500 Topaz (Blue, White) 29 - 32 1.619 - 1.627 Chrysoberyl (Alexandrite) 38 - 42 1.746 - 1.755 common Refractive Index values to get the Calcite 20 - 35 1.486 - 1.658 Danburite 29 - 33 1.630 - 1.636 Pyrope Garnet 38 - 42 1.746 - 1.746 R.I value of the gemstone. -
Spring 1995 Gems & Gemology
TABLE CONTENTS FEATURE ARTICLES 2 Rubies from Mong Hsu Adolf Pelsetti, I(ar7 Schmetzer, Heinz-Jiirgen Bernhardt, and Fred Mouawad " 28 The Yogo Sapphire Deposit Keith A. ~~chaluk NOTES AND NEW TECHNIQUES 42 Meerschaum from Eskisehir Province, Turkey I<adir Sariiz and Islcender Isilc REGULAR FEATURES 52 Gem Trade Lab Notes Gem News Most Valuable Article Award Gems ed Gemology Challenge Book Reviews Gemological Abstracts Guidelines for Authors ABOUT THE COVER: One of the most important ruby localities of the 1990s cov- ers a broad orea near the town of Mong Hsu, in northeastern Myann~ar(B~lrrna). The distinctive gemological features of these rubies are detailed in this issue's lead article. The suite of fine jewelry illustraled here contains 36 Mong Hsu rubies with a total weigh1 of 65.90 ct; the two rubies in the ring total 5.23 ct. jewelry courtesy of Mouawad jewellers. Photo by Opass Sultsumboon-Opass Suksuniboon Studio, Bangltolz, Thailand. Typesetting for Gerrls eS Gemology is by Graphix Express, Santa Monica, CA. Color separations are by Effective Graphics, Compton, CA. Printing is by Cadmus lournal Services, Easton, MD. 0 1995 Gemological Institute of America All rights reserved ISSN 0016-626X - Editor-in-Chief Editor Editors, Gem Trade Lab Notes Richard T. Lidtlicoat Alicc S. I<cller Robcrt C. I<ammerling 1660 Stewart St. C. W. Fryer Associate Editors Smta Mon~ca,CA 90404 William E. Boyajian Editors, Gem News (800)421-7250 ~251 Robcrt C. Kamn~erling Rohcrt C. I<ammerling e-mail: altellcrBclass.org D. Vincent Manson John I. Koivula John Sinltanltas Sr~bscriptions Enirnanuel Fritsch Jln Ll~n Editors, Book llevielvs Technical Editor (800) 421-7250 x201 Susan B. -
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American Mineralogist, Volume 63, pages 664_676, l97g Multisyste_msanalysis of beryiliumminerar stabilities: the systemBeO-A[rOa_SiO2_H2O DoNer.n M. Bunr Department of Geology, Arizona State (Jniuersitv Tempe,Arizona8528I Abstract seven commonly associatedminerals in the systemBeo-Alror-Sior-Hro includechry- soberyl,phenakite, euclase,bertrandite, beryl, kaolinite,and qiuit . The phaserule implies that not more than six of theseminerals can coexistat an invariantpoint, and, with the addition of an aqueousphase, the associationconstitutes an (n * 4; ptrase(negative two d-egreesof freedom)multisystem. The apparentincompatibility of taotinite with phenakite allowsthe splitting of this unwieldymultisystem into two smaller(n + 3) phasemultisystems, which may belabeled (Kao) and (phe).Moiar volumedata, compuier program RrlcrroN, and naturalassemblages can then be usedto derivethe presumablystabie cJnfiguration of these multisystemson p"-minus an isothermal pHro diagram. n, p-r diagramprojected through theaqueous phase shouldhave the sametopology, and cansimilarlf be drawn. on the resultingdiagrams, three . invariant-butpoinis rabeled tchrl, tBr;;, and [etz] arestable in the.multisystem (Kao), and threedistinct identically-fuU"i.Opoint, u.. stablein rhe multisystem(Phe). An implicationof this topologyvia ihe "r.tu.tubl"-rtable correspon- dence,"is that the assemblagephenakite + euclase* beryl(* aqueousphase) has a finite i'I;ix, ii,l'J.?lT"t' ::ff,,,j :r;: :":.T' ? ts why" euclase is muchrarer than bertrandite. and its stabilityfield, especially -
Winter 1998 Gems & Gemology
WINTER 1998 VOLUME 34 NO. 4 TABLE OF CONTENTS 243 LETTERS FEATURE ARTICLES 246 Characterizing Natural-Color Type IIb Blue Diamonds John M. King, Thomas M. Moses, James E. Shigley, Christopher M. Welbourn, Simon C. Lawson, and Martin Cooper pg. 247 270 Fingerprinting of Two Diamonds Cut from the Same Rough Ichiro Sunagawa, Toshikazu Yasuda, and Hideaki Fukushima NOTES AND NEW TECHNIQUES 281 Barite Inclusions in Fluorite John I. Koivula and Shane Elen pg. 271 REGULAR FEATURES 284 Gem Trade Lab Notes 290 Gem News 303 Book Reviews 306 Gemological Abstracts 314 1998 Index pg. 281 pg. 298 ABOUT THE COVER: Blue diamonds are among the rarest and most highly valued of gemstones. The lead article in this issue examines the history, sources, and gemological characteristics of these diamonds, as well as their distinctive color appearance. Rela- tionships between their color, clarity, and other properties were derived from hundreds of samples—including such famous blue diamonds as the Hope and the Blue Heart (or Unzue Blue)—that were studied at the GIA Gem Trade Laboratory over the past several years. The diamonds shown here range from 0.69 to 2.03 ct. Photo © Harold & Erica Van Pelt––Photographers, Los Angeles, California. Color separations for Gems & Gemology are by Pacific Color, Carlsbad, California. Printing is by Fry Communications, Inc., Mechanicsburg, Pennsylvania. © 1998 Gemological Institute of America All rights reserved. ISSN 0016-626X GIA “Cut” Report Flawed? The long-awaited GIA report on the ray-tracing analysis of round brilliant diamonds appeared in the Fall 1998 Gems & Gemology (“Modeling the Appearance of the Round Brilliant Cut Diamond: An Analysis of Brilliance,” by T. -
Weight of Production of Emeralds, Rubies, Sapphires, and Tanzanite from 1995 Through 2005
Weight of Production of Emeralds, Rubies, Sapphires, and Tanzanite from 1995 Through 2005 By Thomas R. Yager, W. David Menzie, and Donald W. Olson Open-File Report 2008–1013 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior DIRK KEMPTHORNE, Secretary U.S. Geological Survey Mark D. Myers, Director U.S. Geological Survey, Reston, Virginia: 2008 For product and ordering information: World Wide Web: http://www.usgs.gov/pubprod Telephone: 1-888-ASK-USGS For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment: World Wide Web: http://www.usgs.gov Telephone: 1-888-ASK-USGS Suggested citation: Yager, T.R., Menzie, W.D., and Olson, D. W., 2008, Weight of production of emeralds, rubies, sapphires, and tanzanite from 1995 through 2005: U.S. Geological Survey Open-File Report 2008-1013, 9 p., available only online, http://pubs.usgs.gov/of/2008/1013. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted material contained within this report. ii Contents Introduction ...................................................................................................................................1 Emeralds.......................................................................................................................................2 -
A PROPOSED NEW CLASSIFICATION for GEM-QUALITY GARNETS by Carol M
A PROPOSED NEW CLASSIFICATION FOR GEM-QUALITY GARNETS By Carol M. Stockton and D. Vincent Manson Existing methods of classifying garnets ver the past two decades, the discovery of new types have proved to be inadequate to deal with 0 of garnets in East Africa has led to a realization that some new types of garnets discovered garnet classification systems based on the early work of recently. A new classification system based gemologists such as B. W. Anderson are no longer entirely on the chemical analysis of more than 500 satisfactory. This article proposes a new system of classifi- gem garnets is proposed for use in gemology. cation, derived from chemical data on a large collection of Chemical, optical, and physical data for a transparent gem-quality garnets, that requires only representative collection of 202 transparent gemquality stones are summarized. Eight determination of refractive index, color, and spectral fea- garnet species arc defined-gross~~lar, tures to classify a given garnet. Thus, the jeweler- andradite, pyrope, pyrope-almandine, gemologist familiar with standard gem-testing techniques almandine~almandine-spessartine, can readily and correctly characterize virtually any garnet spessartine, and pyrope-spessartine-and he or she may encounter, and place it within one of eight methods of identification are described. rigorously defined gem species: grossular, andradite, Properties that can be determined with pyrope, pyrope-almandine, almandine, almandine-spes- standard gem-testing equipment sartine, spessartine, and pyrope-spessartine. Several varie- (specifically, refractive index, color, and tal categories (e.g., tsavorite, chrome pyrope, rhodolite, absorption spectrum) can be used to and malaia*) are also defined. -
Early Diamond Jewelry See Inside Cover
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