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. Johnson Carol M. Stockton Fax: j310) 453-4478 Jana E. ~Miyahira Assistant Editor Contributing Editor Editor, Gemological Abstracts Irv Dierdorff John I. Koivula C. W. Fryer PRODUCHO~ Art Director Production Assistant Word Processor STAFF Lisa Jolto-Cleeson Gail Young Ruth Patchiclc EDITORIN. G. Robert Crowningshield C. S. Hurlbl~t,Jr. Henry 0. A. Meyer REI'IEW BOARD New York, IVY Com briclge, A4A West Lofayefte, IN Alan T. Colli~ls Alan jobbins Kurt Nassau Loi~rlon,United l<ingclom Catcl.hai?l, United 1Zingdorn I'.O. Lebonon, NI Dennis Foltz Anthony R. I<ampf George Rossrnail Snnto Monica, CA Los Angcles, CA I'r~sadenn. CA Ernmanuel Fritsch Robcrt E. I<ane I<cnneth Scarratt Santa Monicc~,CA Helenn, MT Bnngkok, Thailnncl C. W. Fryer john I. I<oivula Sontn Monica, CA Snl~taMonica, CA Henry A. HSmli A. A. Lcvinson James E. Shigley Basel, Switzerlorid Calgorj7, Alberta, Canodn Santrr ~Monico.CA SUBScRlITlONS Subscriptions in thc U.S.A. alc pricctl as follows: S59.95 for onc year (4 ~ssues),$149.95 for ~lirceycars (I2 issucs). Subscriptions sent elscwhere are $70.00 for one year, S180.00 for three ycars. 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Pleasc sce tlic Suggestions for Authors in this issuc of tlic iournal, or contact the editor for a copy. Lclters on articles p~~hlisiietlIn Gems cd Gelnology and other rclcvant rnattcrs are also wclcomc. Abstracting is pcrmittcd with credit to the source. Librarics are permitted to photocopy hcyond the li~n~tsoi U.S. copyright law for privatc use of patrons. Instructors arc permi[tetl to photocopy isolated articlcs for noncommercial classroom use withoi~tfee. Copying of thc photographs by any mcnns other than trad~tionnlplintocopy~ng tcch- nirloes (Xerox, etc.) is prohibited without tlic exprcss pcr~nissionof the photographer (where listed) or author of the ;ir~iclein which the photo appears (wherc no photographer is listcd). For other copying, rcprint, or repubIic:it~on pcr- mission pIease contact thc editor. Gems d Gelllology is published quarterly by thc Gemological Inst~tutcof America, a nonprofit educational organi- zation for the iewclry industry, 1660 Stewart Street, Santa Monica, CA 90404. Postmastcr: Rcti~rnilndelivcrahlc copics of Gems eJ Ge117olo~yto 1660 Stewart Strcet, Santa Monica, CA 90404. Any opinions expressed in s~gneda~ticlcs are understooil to be the opinions of the authors ant1 not of the pi~blislicrs. LETTERS KUDOS FOR "COLOR GRADING SAPPHIRE-BEARING ALKALI OF COLORED DIAMONDS" BASALTS IN NIGERIA Congratulations to the authors of the report With grcat interest I read the article "Gem "Colored Grading of Colored Diamonds in the Corundunl in Allcali Basalt: Origin and GIA Genl Trade Laboratory," by Icing, Moscs, Occurrence," by Drs. Levinson and Cook, in the Shigley, and Liu, which appeared in the Winter Winter 1994 issue (pp. 253-262). However, I '94 issue of Gems & Geniology (pp. 220-2421, It would like to updatc the inforination in onc is a superb achievement. I am so impressed that I remarlc, on page 256: "Significantly, all reported feel coinment is appropriate. economic, and potentially economic, secoildary I was very concerned when I first learned occurrences of basaltic corundurn are spatially that the GIA was preparing an article on their associated with the alkali typc of basalt. (Coen- color-grading system for colored diamonds. The raads et al., 1990, illention two possiblc excep- measureinent of color for paints and other tions, in Nigeria and Southcrn China, but these opaque surfaces is a quite routine matter, but are not well documented.)" transparent substances present complicatio~~s. In the Iournal of Gemmology, 1990, Vol. 22, There are additional problems that arise with the No. 4 (pp. 195-2021, J. Icanis and R. R. Harding ineasurenlent of color in facetcd gemstones, published an article titled "Gemstone Prospects including the variations of color with 01-ienta- in Central Nigeria," in which we described thc tion, across the stonc, face up versus face down, occurrence of sapphircs and zircons of the Jemaa and so on. Much nonsense has been written on district, in central Nigeria. We coinpared the this subject. Jenlaa alkali basalts with thc occurrcnccs in I need not have worried; publication of this Australia, Thailand, and Kampuchea. article has put all illy concerns to rcst. The Froin our description, it is evident that the authors (as well as the ~nallyothers within GIA vast sapphire deposits in central Nigeria are not who helped) are to be congratulated on an excel- "a possible exception," but definitely belong to lent solution to a difficult taslc. They appear to thc alkali type of coruildum occurrencc. have covered all the problems that could arise in JAN KANIS, Ph.D. normal practice. I bclieve the terlninology grid, Veitsrodt, Germany which they based on the time-tested Munsell and ISCC-NCS approaches, is also lilcely to sur- vive the test of time. Their technique is extreme- Reply and Erratum ly well presented in the article; no doubt the edi- We regret that we imissed the paper by I<anis and tors also deserve some credit for this. Harding in our literature search, and wc thanlc I hope that the GIA will continue to publish Dr. Kanis for bringing this to our attention. details on their grading system as inore informa- We would like to talce this opportunity to tion becomes available in the future. correct an error in the caption to figure 6 (p. 260) So again: Congratulations! in our paper: the longest corundum crystal is 1.3 KURT NASSAU, Ph.D. cin (about 0.5 inches), not 13 cm (about 5 inches). Nassou Cons~ll~ants A. A. Levinson, Ph.D. and Fred Cook, Ph.D. Lebanon, New lersey Calgary, Alberta, Canadn GEIMS W GEMOLOGY By Adof Pesetti, Karl Schmetzes, Heinz-Jiirgen Bernhadt, and Fred Mouawad Large quantities of rubies-both rough and ince 1992, Mong Hsu has been a primary source of ruby faceted-fron~ a con~merciollyimportant available in Thailand (figure 1).Mong Hsu is a small town new source in Myanmar (Buirn~n)hmve been Ssituated in northeastern Myanmar (formerly Burma) in avaiIcrble on the Bangltolt inarltet since 1992. Shall State, which borders Thailand, Laos, and China. The nzby crystrrls from the Mong Hsu marble Untreated samples from this new source typically consist of deposit have clipymmidnl to barrel-shaped bicolored corundum, with dark violet to almost black sap- hobils and reverrl dark violet to almost black phire cores and ruby rims (figure 2). With heat treatment, "cores" 017d red "rims." With heat treatment, which removes their blue color componer~t, the violet cores can be converted to red. Large quantities of the cores become intense red. The rubies grew untreated corundum crystals are brought into Thailand at umder varying conditions in complex growth Mae Sai and, to a lesser extent, at Mae Hong Son (see figure sequences. The color distribution between 3). In 1993, about 200 buyers from Chantaburi (Thailand) cores and rims is related to a different incor- were spending several million U.S. dollars a month on poration of chrorniun~andlor titanium during Mong Hsu rough in Mae Sai ("Special report: Mong Hsu .