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WINTER 1989 Volume 25 No. 4

TABLE OF CONTENTS

EDITORIAL Reflections on the 1980s Richard T Liddicoat

FEATURE and Treasures of the Spanish Galleon ARTICLES Nuestra Seiiora de Atocha Robert E. IZane, Robert C. IZammerling, Rhyna Moldes, John I. Koivula, Shane E McClure, and Christopher P. Smith from the Harts Range, Northern Territory, Australia Maxwell J Faulkner and lames E. Shigley Blue from the Dominican Republic Robert E. Woodr~lf/and Emmanuel Fritsch

NOTES Reflectance Infrared Spectroscopy in AND NEW E Martin, H. Merigoux, and P. Zecchini TECHNIQUES Mildly Radioactive Rhinestones and Synthetic -and-Glass Triplets Knit Nassau and Edward A, Lewand

REGULAR Gem Trade Lab Notes FEATURES Gem News Book Reviews Gemological Abstracts Annual Index

ABOUT THE COVER: During the 1600s the Spanish conquerors of the New Worldshipped tons of gold, , and back to their mother country. They also sent back thousands of carats of rough and jewel-set . This rosary was one of the many emerald treasurers b~oughtup from the sunken Nuestra Senora de Atocha during the past decade. It had been in its underwater tomb for over 350 years. Staff at the GIA Gem Trade Laboratory and their colleagues have examined several of the emerald and gold treasures recovered from the shipwreck; they report their gemological discoveries and observations on the goldwork in this issue. Photo by Shane i? McClure, CIA Gem Trade Laboratory, Santa Monica, CA. Typesetting for Gems & Gemology is by Scientific Composition, Los Angeles, CA. Color separations are by Effective Graphics, Compton, CA. Printing is by Waverly Press, Easton, MD.

0 1990 Gemological Institute of America All rights reserved ISSN 001 6-626X EDITORIAL Editor-in-Chief Editor Editor, Gem Trade Lab Notes STAFF Richard T. Liddicoat Alice S. Keller C. W. Fryer Associate Editors 1660 Stewart St. Editor, Gemological Abstracts Willian~E. Boyajian Santa Monica, CA 90404 Dona M. Dirlam Peter C. Kcller Telephone: (8001 421-7250 x25 1 D. Vincent Manson Subscriptions Editors, Book Reviews John Sinlzankas Bruce Tucker, Manager Elisc B. Misiorowslzi Technical Editor Telephone: (800)421-7250 x201 Loretta B. Loeb Fax: (213) 828-0247 Carol M. Stockton Editors, Gem News Editorial Assistant Contributing Editor John I. Koivula Nancy K. Hays John I. Koivula Robert C. Kammerling

PRODUCTION Art Director Graphics Supervisor Word Processor STAFF Lisa Joko Robert Cultrera Ruth Patchick

EDITORIAL Robert Crowningshield Robert C. Kammerling Sallie Morton REVIEW BOARD New York, LVY Santa Monica, CA Sun lose, CA Alan T Collins Anthony I<. Kampf Kurt Nassau London, United Kingdom Los Angeles, CA PO. Lebanon, N[ Dennis Foltz Robert E. Kanc Ray Pagc Santa Monica, CA Santa Monica, CA Santa Monica, CA Emmanuel Fritsch John 1. Koivula George Rossman Santa Monica, CA Santa Monica, CA Pasadena, CA C. W. Fryer Henry 0. A. Meyer Karl Schmetzer Santa Monica, CA West Lafayette, IN Heidelberg, W. Germany C. S. Hurlbut, Jr. James E. Shigley Cambridge, MA Santa Monica, CA

SUBSCRIPTIONS Subscriptions in the U.S.A. are priced as follows: S39.95 for one year (4 issues), $94.95 for three years (12 issues). Subscriptions sent elsewhere are $49.00 for one year, S124.00 for thice years. Special annual subscription rates arc available for all students actively involved in a CIA program: $32.95 U.S.A., $42.00 elsewhere. Your student number must be listed at the time your subscription is entered. Single issues may be purchased for $10.00 in the U.S.A., $13.00 elsewhere. Discounts are given for bulk orders of 10 or more of any one issue. A limited number of back issues of G&G are also available for purchase. Please address all inquiries regarding subscriptions and the purchase of single copies or back issues to the Subs criptions Manager. For subscriptions and back issues in Italy, please contact Istituto Geinmologico ~Mcditerraneo,Via Marn~olaia#14, 1-38033, Cavalese TN, Italy. To obtain a Japanese translation of Gems el Gemology, contact the Association of Japan Gem Trust, Okachimachi Cy Bldg, 5-15-14 Ueno, Taito-ku, Tokyo 110, Japan. MANUSCRIPT Gems a) Gemology welcon~esthe submission of articles on all aspects of the field. Please see the Suggestions for SUBMISSIONS Authors in the Spring 1989 issue of the journal, or contact the editor for a copy. Letters on articles published in Gems sl Gemology and other rclcvant matters are also welcomc. COPYRIGHT Abstracting is permitted with credit to the source. Libraries are permitted to photocopy beyond the limits of U.S. AND REPRINT copyright law for private use of patrons. Instructors are permitted to photocopy isolated articles for noncon~mercial PERMISSIONS classroom use without fee. Copying of the photographs by any means other than traditional photocopying techniques (Xerox, etc.) is prohibited without the express permission of the photographer (where listed) or author of the article in which the photo appears (where no photographer is listed). For other copying, reprint, or republication pern~ission, please contact the editor. Gems d) Gen~ologyis published quarterly by the Ccn~ologicalInstitute of America, a nonprofit educational organization for the jewelry industry, 1660 Stewart St., Santa Monica, CA 90404. Postn~aster:Return imdeliverable copies of Gems a) Gemology to 1660 Stewart St., Santa Monica, CA 90404. An'y opinions exprcssed in signed articles are understood to bc the views of the authors and not of the publishers Reflections on the 1980s

he past decade has been one of significant changes in the and colored Tstone industry with a potential impact that is perhaps unparalleled in modern gemology. We began this decade with major upheavals in the diamond market and are ending it with that market stronger than ever. We have seen colored stones reach new heights in availability and consumer awareness. New localities have been found, as have several unusual varieties of old favorites (witness the new Paraiba ). Perhaps most challenging of all have been the technological advances: The broader use of heat treatment and irradiation, the application of a process that actually fills cleavages in diamond, the appearance of new synthetic emeralds and corundum, and the unprecedented commercial availability of gem- quality synthetic have brought new demands in gem identification and evaluation. They have also spurred the introduction of new techniques (infrared spectroscopy for one) into the gemology laboratory. t ' W; at Gems s? Gemology are proud to have published the first in-depth reports on many of these new localities, new treatments, new synthetics, and new identifica- tion techniques. The 1980s also marked the introduction of the larger format, full- color GdG, with a mandate to supply the most thorough and current gemological information to the international gem community. To close the 1980s and look forward to the final decade of the second millenium, we have asked a number of prominent gemologists and researchers to summarize the key developments of the last 10 years in gem localities, treatments, synthetics, technology and jewelry manufacturing and design, as well as provide a preview of the '90s. These articles will be presented in a special, expanded Spring 1990 issue and will serve as the springboard with which we plan to "face the future" at the June 1991 International Gemological Symposium, In the future, as we have in the past, Gems es) Gemology will continue to keep you informed of the latest and most significant events in this exciting field.

Richard T. Liddicoat Editor-in-Chief

Editorial GEMS &. GEMOLOGY Winter 1989 195 EMERALD AND GOLD TREASURES OF THE SPANISH GALLEON NUESTRA SENORA DE ATOCHA

By Robert E. Kane, Robert C. Kammerling, Rhyna Moldes, John I. Koivula, Shane F. McClure, and Christopher l? Smith

During the 1970s and 1980s, treasure uring the Spanish conquest of the New World in the hunters discovered the centuries-old re- D 1500s, conquistadores discovered vast amounts of mains of the sunken Spanish galleons valuable commodities such as gold, silver, copper, indigo, Nuestra Senora de Atocha and Santa Mar- , and emeralds. The last of these, emeralds, was one of garita. Not only did they find massive the rarest items-with only the exhausted Egyptian de- amounts of silver and gold in coins, bars, posits then lznown to the Western world. Gold and silver and chains, but they also uncovered a number of rough emeralds and several were mined in Upper Peru (now Bolivia), Mexico, and the pieces of emerald-set jewelry. Recently, area that was eventually lznown as New Granada (Colom- some of the treasures recovered from the bia, parts of Venezuela, Ecuador, and Panama). In 1537, Atocha were examined at the Santa Gonzalo Jimenez de Quesada was pursuing his conquest of Monica office of the GIA Gem Trade Lab- the interior of Colombia when his men located emerald oratory. Gemological testing of the emer- deposits in an area then called and later named alds revealed inclusions typical of stones . Subsequently, emerald deposits were also found at mined in Colombia as well as possible ev- , with its even larger (and, many consider, finer) idence of extended submersion in sew- crystals. The Spaniards quickly enslaved the local tribes ter. Study of the jewelry revealed a high- and forced them to work the mines, as they had done karat gold content and fine workmanship elsewhere (Keller, 1981). Many emeralds, both set in that represented methods typical of the era. jewelry and as rough crystals (figure l),were subsequently sent to Spain. Spain set up a sophisticated system of delivery and piclz- up to and from the New World and Asia using fleets of cargo vessels guarded by warships (Lyon, 1982; Mathew- ABOUT THE AUTHORS son, 1987). On September 4, 1622, the cargo vessels and Mr. Kane is a supervisor of gem identification in the galleons of the Tierra Firme fleet set sail from Havana, GIA Gem Trade Laboratory, Inc., Santa Monica, Cuba, carrying many noblemen and their families, as well California. Mr. Kammerling is general manager of technical development, GIA, Santa Monica. Ms. as soldiers, slaves, and priests. Besides the personal effects Moldes is a graduate gemologist and president of the passengers, the cargo of the heavily armed rear of International Eximgems, Miami, Florida, Mr. galleon Nuestra Senora deAtocha included 901 silver bars, Koivula is chief gemologist, GIA. Mr. McClure is a senior staff gemologist, and Mr. Smith is a staff 161 gold bars or disks, and about 255,000 silver coins (Lyon, gemologist, in the GIA Gem Trade Laboratory, 19761, along with copper ingots and, although not entered Inc., Santa Monica. into its manifest, emeralds. Soon after leaving port, a Acknowledgments: The authors thank Mr. Me1 Fisher and Mr. R. D. LeClair for providing informa- tion and the opportunity to examine the materials Figure 1. These rough emeralds and emerald-set and gold for this investigation. jewelry, found in the main body of the wrecked 17th-century Gems & Gemology, Vol. 25, No. 4, pp. 196-206 Spanish warship Nuestra Senora de Atocha, are the subject of 0 7990 Gemological Institute of America this investigation. Photo by Shane F. McClure.

196 Treasures of the Atocha GEMS & GEMOLOGY Winter 1989 ferocious hurricane ravaged the convoy; the At- nons very near the "Bank of Spain"; later, the crew ocha and another galleon, the Santa Margarita, found four more cannons close to the first group. also heavy with cargo, were two of eight ships Some of these bore recognizable marks, which dashed against the reefs of the Florida Keys (figure matched those indicated in the Atocha's docu- 2). Over the next few years, Spanish salvors en- ments. Only a few days later, though, diving came listed the help of local native divers, with to a tragic halt after Dirk, his wife, and another their rudimentary diving techniques, to search for member of the crew perished when their vessel the ships and recover their cargo (Christie's, 1988); sank. they had some success with the Santa Margarita, The search eventually resumed and a variety of but very little with the Atocha (Lyon, 1976, 1982). artifacts were recovered over the next five years, In all, only 380 silver ingots, 67,000 silver coins, but not the actual hulls with the bulk of the cargo. and eight cannons were recovered (Mathew- "Mailboxes" (huge metal conduits designed by son, 1986). Eventually, the remains of the ships Fisher to pump clear water to the bottom of the were swept farther out to sea and forgotten. ocean to increase visibility and remove sand from the wreck site) aided their efforts. Finally, in June MODERN RECOVERY 1980, the searchers located six silver ingots, copper OF THE TREASURES ingots, and thousands of silver coins surrounded In the early 1960~~almost 350 years after the by ballast and shipwreck debris. From the mani- sinking of the galleons, treasure hunter fest, the crew determined that they had found the and a group of collaborators arrived in Florida hull of the Santa Margarita. During the next two determined to find Spanish shipwrecks in the seas years they recovered 43 gold chains with a total off the peninsula. After considerable success with length of 180 feet and a concentration of gold bars other recoveries, the group decided in the late worth an estimated $40 million (Mathewson, 1960s to search for the Atocha and the Santa 1987). Yet the treasures of the Atocha remained Margarita. R. Duncan Mathewson, the operation's elusive. archaeologist, detailed the recovery efforts exten- In 1985, however, two divers came across what sively in his book, Treasure of the Atocha (1987). they thought was a reef; it turned out to be While studying the history of Spanish Florida in silver bars and coins. Then they noticed the Spain's Archives of the Indies, Dr. Eugene Lyon wooden beams in the area: They had finally found came across Francisco Nunez Meli5n's 17th-cen- the main hull of the Atocha. The searchers eventu- tury account of the salvage of the Santa Margarita ally brought up seven chests filled with 2,000 (Lyon, 1976). This document specified that the silver pieces each and an eighth filled with gold ships had gone down near the Cayos del Marquez bars [Starr et al., 1985).An added bonus, not on the (Keys of the Marquis), a group of islands situated manifest, were hundreds of rough emeralds-over between Key West and Dry Tortugas. Recovery 2,300 according to a 1986 article in the Los Angeles efforts started in earnest. Times. In June 1971, divers found the anchor of the Many gold artifacts and jewels set with gems, Atocha and a lead m~isketball(Lyon, 1976, 1982). including emeralds, also were found in the wreck Days later, professional underwater photographer (figure 3).One emerald , an engraved piece that Don Kincaid discovered a gold chain 8Vz feet (259 still retains part of the black enameling in the cm) long. Not until 1973, however, did the Fisher shank, was sold at Christie's New York in June group recover any significant treasure: approx- 1988 for $79,200. Many of the emeralds and other imately 4,000 silver coins and other objects (inclu- artifacts are on exhibit at the museum of the Me1 ding swords, some gold coins, and a rare navigation Fisher Maritime Heritage Society in Key West, instrument known as an astrolabe) found in an Florida. area called the "Bank of Spain" (Mathewson, 1986). They still didnot know if they had found either the THE EMERALDS AND Atocha or the Santa Margarita; only when they GOLD TREASURES STUDIED encountered the main hulls and compared their Several of the items recovered from the Atocha contents with those listed in the ships' manifests were recently submitted to the GIA Gem Trade would they be able to establish proof of the source. Laboratory for examination. These included In July 1975, Fisher's son Dirk found five can- (again, see figure I): seven rough emerald crystals

198 Treasures of the Atocha GEMS & GEMOLOGY Winter 1989 Figure 2. The 28 ships of the Tierra Firme fleet were laden with goods obtained on the summer trade circuit through the Caribbean colonies as well as those brought from Manila. Weeks behind schedule, they left Havana during hurricane season, and were caught in a violent storm on only the second day out of port. The Santa Margarita and the Atocha went down in sight of each other, with six other ships lost over a course of 50 miles (Lyon, 1982). Painting by Richard Schlecht; by Julian Waters; compiled by John R. Treiber; courtesy of the National Geographic Arl division.

ranging from 3.69 to 64.46 ct; one gold rosary and was an engraved gold spoon with minor remaining crucifix set with nine cabochon emeralds (the (figure 4). largest is an 8.9-mm round cabochon); two gold rings each set with a single emerald (6.7 x 7.3 mm GEMOLOGICAL DESCRIPTION and 8.6 x 8.9 mm, respectively); one gold OF THE EMERALDS set with a large (9.9 x 14.9 mm)rectangular step- A gemological investigation of all the emeralds, cut emerald; and one gold chain. Also examined both rough and fashioned, was carried out in order

Treasures of the Atocha GEMS & GEMOLOGY Winter 1989 199 prisms, the most common form of crystalli- zation (Sinlzanlzas, 1981). Five were terminated at one end with pinacoidal faces; one displayed pin- acoidal terminations at both ends, with only a small broken surface where it had been attached to the matrix; and one exhibited only hexagonal prism faces, with both ends broken. Most of the emeralds set in jewelry, with the exception of two cabochons suspended from the crucifix, were bezel set in closed-back mountings, limiting visual examination. The two step- cut stones mounted in gold rings were both moder- ately included, with one a medium green and the other a medium-dark green. The nine cabochons set in the crucifix were very well matched for color and transparency: medium to medium-dark green and lightly to moderately included. Six of these cabochons had small polished concave surfaces on their exposed areas. The largest faceted stone (9.9 x 14.9 mm) was set in a brooch (figure 6). The stone revealed no inclusions to the unaided eye and appeared to be very dark green (almost black) with virtually no brilliance. The reasons for the exceptional dark- ness and lack of internal reflection were discovered during the microscopic examination (see below],

Refractive Indices and . We obtained R.I.'s using a Duplex I1 refractometer in conjunc- tion with white light for the rough crystals and the cabochons and a -equivalent light source for the faceted stones. Because of irregularities on the unpolished surfaces, including surface , Figure 3. The crucifix depicted on the cover of we could only obtain a very vague shadow reading this issue and in figure 1 was recovered by of 1.58 on the seven crystals. Clearer spot readings divers in 1986, approximately 100 feet (35 m) of 1.57 or 1.58 were obtained on all nine of the from the main wreck site of the Atocha. Photo cabochons set in the crucifix. The faceted emerald 0 Don Kincaid. in the brooch and the larger ring-set emerald were determined to have refractive indices of e = 1.570 to document the properties of these historically and to = 1.578, with a birefringence of 0.008. The significant stones as well as to determine if there faceted stone in the other ring read slightly higher, was any evidence of their long submersion in the e = 1.572 and to = 1.580. These refractive indices sea. are consistent with those reported in the literature for emeralds originating in Colombia (Sinlzankas, Visual Appearance. The seven emerald crystals 19811. While the birefringence determined for the ranged from transparent to translucent and from three faceted stones is higher than that reported for medium to dark tones of green to slightly bluish , in the authors' experience green (figure 5). We observed scattered white this value is in fact quite common for stones from patches on the surfaces of most of the crystals; this country. Although birefringence could not be these were especially prominent on the 30.34-ct determined on the rough crystals or the cabochons, and 64.46-ct pieces. their doubly refractive nature was confirmed with The crystals were all first-order hexagonal a polariscope and/or dichroscope.

200 Treasures of the Atocha GEMS & GEMOLOGY Winter 1989 Figure 4. These emerald crystals from the Atocha are sitting in a large gold spoon that was also among the items recovered from the galleon. The ornate handle still shows remnants of some type of inlay. Photo by Shane E McClure.

Pleochroism. Using a calcite dichroscope, we ob- Chelsea Filter Reaction. When viewed through a served dichroism in strongly distinct colors of Chelsea filter, all seven crystals displayed a spec- bluish green parallel to the c-axis and yellowish tacular saturated dark red, a reaction consistent green perpendicular to the c-axis in all seven with that described in the literature for Colombian crystals. T^bkse results are typical of many natural emeralds (Webster, 1983). The mounted emeralds emeralds (Webster, 1983). exhibited a red reaction of varying intensity.

Figure 5. The seven emerald crystals examined (3.69-64.46 ct) ranged from transparent to translucent and from green to slightly bluish green. The chain surrounding the crystals is one of many from the Atocha wreck site. It has been suggested that the chains were worn as jewelry to try to escape taxation; individual links could be removed and used as coinage (Lyon, 1982). Note the draw lines on the links, evidence of the relatively crude technique used. Photo by Shane F. McClure.

Treasures of the Atocha GEMS & GEMOLOGY Winter 1989 201 Reaction to Ultraviolet Radiation. The crystals themselves appeared inert to long-wave U.V radia- tion. However, there was an extremely wealz to mod- erate challzy yellow-green fluorescence in some surface-reaching fractures and cavities. All but one of the crystals had a similar, but much wealzer, reaction to short-wave U.V The exception, the largest crystal (64.46 ct), fluoresced an extremely wealz, patchy orange, possibly due to the presence of carbonaceous inclusions. Looking down the c-axis of all of the crystals while they were exposed to long-wave U.V radiation, we also noted that the weak fluorescence seemed to be confined to less than 1 mrn of the periphery of the crystals. All of the fashioned stones were essentially inert to both long- and short-wave U.V radiation, al- though a few exhibited a very weak challzy yellow- green fluorescence to long-wave U.V in small surface-reaching fractures. Furthermore, the large faceted emerald in the appeared to fluo- Figure 6. This brooch contained the largest resce a weak challzy yellow-green from within, faceted stone examined, measuring 9.9 x 14.9 rather than from irregularities in the exposed mm. The dark appearance of this otherwise fine surfaces. emerald is caused by the combination of a The chalky yellow-green fluorescence in some of relatively shallow pavilion, seawater trapped in the fractures was surprising, since it is usually the setting, and corroded remnants of the associated with emeralds that have had surface- back~ng.Photo by Shane F. McClnre. breaking fractures oiled to make them less appar- ent. Microscopic examination showed that there Absorption Spectra. The visible-light absorption was no liquid of any kind in most of the fractures. spectra of the seven crystals, examined with a Beck While two of the rough crystals did exhibit some prism spectroscope, appeared to be essentially the form of liquid in a few fractures (figure 71, subse- same as those for emeralds described by Liddicoat (1989, p. 135).When looking down the optic axis direction, we observed a vague general absorption Figure 7. This system in one of the from 400 nm to approximately 480 nm, a sharp line emerald crystals contained a liquid that did at 477 nm, a broad band of absorption between 580 not react like the oils commonly used to treat emeralds today. Photon~icrographby lohn 1. and 615 nm, and lines in the red at 637, 646, 662, Koivula: darkfield illumination, magnified 10 x . 680, and 683 nm. We observed a similar spectrum perpendicular to the optic axis, but the sharp line at 477 nm was absent. The saturated color and thickness of some of the crystals caused a very strong dark, nearly black absorption in many areas of the visible-light spectrum, which tended to mask the 477-nm line even when the spectrum was viewed parallel to the c-axis. The same basic absorption pattern, although weaker, was observed in all of the mounted emer- alds. Limitations imposed by the mountings made it impossible to examine the stones both parallel and perpendicular to the c-axis. Using a polarizing filter, however, we did observe the 477-nm line associated with the ordinary ray.

202 Treasures of the Atocha GEMS & GEMOLOGY Winter 1989 quent testing indicated that it was not an oil like those commonly used to treat emeralds. Specifi- cally, when a thermal reaction tester (hot point), was applied the liquid flowed more rapidly within the fractures than do the typical oils. The liquid also did not "sweat out" of the fractures and up on the surface, as will oils used in emerald treatment; it did "sweat out" but most of it then quickly evaporated. It is possibile that the fluorescence reaction was caused by the residue from an oil that had seeped out and/or had been flushed out by the action of water during the approximately 350 years the pieces sat on the ocean floor. Another alternative is that the crystals were stored in oil after recovery. Or the reaction might be due to something natu- rally present in the seawater environment. A Figure 8. High magnification (200X) revealed number of additional observations supported this minute fluid inclusions in the solid phase of last theory. this three-phase inclusion in one of the Atocha emeralds. Photomicrograph by John I. Koivula; According to expedition diver D. LeClaire, a R. transmitted light. number of the emeralds that appeared very trans- parent when found underwater and when first faceted stone in the brooch exhibited a red trans- brought to the surface subsequently became much mission luminescence; the reaction was very less transparent. This observation would be con- strong. sistent with water-filled fractures drying out on extended exposure to air. In addition, as mentioned Specific Gravity. Using a Mettler AM100 elec- above, the weak challzy yellow-green fluorescence tronic scale equipped with the appropriate attach- of the brooch-set emerald appeared to come from ments, we made at least three hydrostatic weigh- within and not from the exposed upper surfaces. ings for each of the crystals. Specific gravity values Microscopic examination (covered in more detail of 2.67 to 2.71 were determined. We attributed the below) revealed a liquid (seawater?)trapped be- relatively low values for several of the crystals to neath the emerald within the bezel setting. Exam- bubbles trapped in large surface-breaking cavities ination of this stone with magnification and while as well as to gaseous phases in multi-phase fluid exposed to long-wave U.V radiation revealed that inclusions within these stones (see the Micro- this trapped liquid fluoresced a challzy yellow- scopic Examination section below). Significant green; the fluorescence could actually be made to quantities of trapped gaseous inclusions can de- "flow" as the pendant was rocked back and forth, crease specific gravity in emeralds just as, for allowing the gas bubble to move. example, pyrite inclusions (S.G. 4.95 to 5.10) can The authors feel that the challzy yellow-green significantly increase it. The S.G. range deter- fluorescence exhibited in areas of some of the mined is consistent with that reported in the emeralds is probably due to some fine precipitate literature for Colombian emeralds (Sinlzankas, of seawater that has entered surface breaks. 1981). Luminescence to Visible Light. Some gems appear Microscopic Examination. All of the emeralds red when illuminated with intense transmitted exhibited classic three-phase inclusions of the type light. This reaction is typical of many - associated with Colombian localities. These inclu- colored materials, including various synthetic em- sions ranged from less than 0.1 mm to slightly over eralds. It is also seen, infrequently, in some natural 1 mm in the long direction. All had a jagged outline emeralds, such as fine-quality stones from Chivor and contained a gas bubble and one or more cubic and some medium- to light-toned emeralds from crystals (figure 8). In addition, all were oriented another Colombian locality, Gachala (Kane and parallel to the prism faces, indicating that they Liddicoat, 1985). Of the study group, only the were primary (i.e., they did not result from the

Treasures of the Atocha GEMS & GEMOLOGY Winter 1989 203 Figure 10. Surface etching was noted on all of the emerald crystals examined. Photo- micrograph by John I. Koivula; oblique illumination, magnified 6 x .

hydrothermally grown natural crystals, frequently shows surface etching caused by dissolution (Sin- lzanlzas, 1981). One of the most interesting discoveries during the microscopic examination was the cause of the very dark, dull appearance of the faceted brooch- set emerald. We knew that the relatively shallow pavilion would create a "window" effect, the result of unplanned light leakage, that would seriously Figure 9. Dolomite crystals were exposed on the diminish brilliance. However, closer examination fracture surface of this 15.12-ct Atocha emerald revealed that the fairly large space between the crystal. Photomicrograph by Robert E. IZane; pavilion facets of the stone and the back of the oblique illumination, magnified lox. mounting contained a liquid (thought to be seawa- ter) that had probably been forced in by the healing of fractures).In some instances, relatively pressure exerted on the piece during burial at sea high magnification (200 x ) revealed primary fluid over three and a half centuries. This liquid, which inclusions within the solid phases of the three- contained a large movable air bubble (figure 11), phase inclusions (again, see figure 8). caused a partial immersion effect that undoubt- Several translucent crystals were exposed on a edly contributed significantly to the stone's lack of fracture surface of the 15.12-ct crystal (figure 9). brilliance. Finally, what appeared to be the re- These were first tested with a minute drop of mains of a reflective backing were trapped in the dilute (10%)hydrochloric acid solution which space and floated about as the liquid was agitated. produced an effervescence characteristic of carbo- The authors speculate that this backing may have nate . X-ray diffraction analysis showed been silver that corroded over time, further con- an exact match with dolomite. tributing to the dark appearance of the emerald. All of the rough crystals showed surface etching (figure 10). Some, most notably the two largest, SOME OBSERVATIONS showed a considerable amount of what appeared to ON THE GOLD WORK be very deep etching on the prism faces. Micros- Most of the jewelry we examined appeared to be copy revealed that this was caused by superficial cast, except for the two chains and some compo- etching that had broken into near-surface fluid nents of the brooch and rosary. The process inclusions which apparently subsequently was probably an early form of the modern-day lost- drained. Even on those faces that appeared rela- wax casting technique, which uses a wax carving tively smooth to the unaided eye, magnification encased in a thick, porous clay mixed with revealed very fine etch figures. Emerald, like other coarsely ground charcoal (Mitchell, 1985). Al-

204 Treasures of the Atocha GEMS & GEMOLOGY Winter 1989 Figure 11. Close examination of the brooch revealed liquid and a large gas bubble between the pavilion facets of the emerald and the back of the bezel setting. The black residue trapped between the emerald and the mounting in the pendant may have been the remains of a silver coating on either the pavilion facets of the stone or on the inner surface of the bezel itself. Slight movement of the brooch caused the bubble and the residue to move freely. Photomicrograph by Robert E. Kane; oblique illumination, magnified 10 X. - though sand casting (i.e., casting from a negative also been soldered to opposite sides of the backing, impression made in sand; Hayward, 1976)was also probably so that the piece could be used with a pin. popular in Europe at this time, the detail on the The rosary presented an intriguing jewelry examined makes it unlikely that this mystery: All of the beads were missing, with only coarser technique was used. a series of opposing bell caps remaining (figure 1). The metal was soft and appeared to be of high Although one theory is that the beads might have karat gold. Thornton Mann, of the GIA Jewelry been pearls (M. Fisher, pers. comm., 1989), this is Manufacturing Arts Department, performed an unlilzely given the relatively large size of the acid test aha portion of the rosary and determined spaces and the fact that no remnants remained. it to be slightly less than 24K. All of the pieces were Although badly corroded, recognizable pearls were a deep yellow color except for one gold chain (46in. recovered from the wreckage of the Atocha (Math- long, 15.8 troy oz.) that was slightly greener and ewson, 1987). It is more likely that these were less saturated. XRF analysis of this piece by the wooden beads, which were commonly used in GIA Research Department determined the pri- rosaries, and which would have deteriorated rap- mary elements to be gold, , silver, and idly in seawater (D. Kincaid, pers. comm., 1989). , with trace amounts of iron and copper. The emerald-set crucifix hanging from the neclz- As would be expected of a chain from this era, the was ornately carved. It is typical of those worn surface of the metal was very uneven, with fea- by high church officials and European nobility tures characteristic of a rudimentary drawing during this era (Muller, 1972). The several bezels process (see figure 5). were actually cast as a single piece, not as individ- The emerald brooch was a particularly fine ual bezels soldered together. They were firmly example of New World goldsmithing (figure6). The attached to the main body of the crucifix by several bezel setting was burnished with such accuracy raised metal pegs, with no solder present. that the stone was held by pressure applied at the The gold spoon (11.3 cm long, 1.9 1 troy oz.) girdle, with very little metal actually extending consisted of a large basin and an intricately carved onto the ; in fact, at one corner a small handle (figure4). These were held together by only portion of the upper girdle was exposed, with two crimped pegs; again, no solder was used. The the gold bezel firmly against the girdle edge. The pegs appear to have worn with time, so that there is metal folded onto the crown was burnished to a now movement between the two pieces and the thin edge for a perfectly flush seal. This was joint is very fragile. carried out with such precision that magnification Both the back of the crucifix and the handle and revealed tiny gold remnants pressed into shallow baclz of the spoon were intricately engraved (figure abrasions in the emerald where the bezel and facet 121, with deep figures and channels that were met, leaving the metal at a relief no higher than rough in texture, typical of used for that of the facet. The plate on the baclz of the enameling (C. Weber, pers. comm., 1989). David emerald was initially held in place by a series of Callaghan, of the Gemmological Association of raised pegs that were subsequently soldered for a Great Britain, suggested to the authors that niello, more permanent seal. A pair of square arches had another material also popular during this period,

Treasures of the Atocha GEMS & GEMOLOGY Winter 1989 205 Figure 12. Note the intricate engraving on the back of the spoon and the crucifix. The rough nature of the engraving suggests that it was all inlaid at one time. Photo by Shane F. McCl~~re.

may have been used instead of enamel. Niello is an ter - birds - is more compatible with colors possi- opaque dark gray to black metallic mixture of ble only with enamel. sulphur, silver, copper, and lead that is ground into small grains, no; powdered; enamel is a seini- SUMMARY transparent to opaque glass of varying composi- The gemological properties of the emeralds exam- tion that is ground to a fine powder (Ashbee, 1967). ined for this article are consistent with those Both materials are applied and finished by similar reported in the literature and noted in the experi- techniques. The delicate artistry on the back of the ence of the authors for emeralds from Colombia. cross suggests that enameling was probably used Some features could be attributed to the immer- here to better display the engraver's workmanship sion of the stones in seawater for an extended while adding color to the intricate scenes depicted. period of time. Channels on the handle of the spoon, however, still The jewelry represents superb craftsmanship, contained severely etched, slightly granular re- using several techniques popular in the early 17th- mains of what could have been the coarser niello. century. These include early forms of lost-wax The crudeness of the engraving on the back of the casting and chain drawing, as well as examples of spoon basin suggests the use of either niello or a stone setting and engraving that rival any seen more opaque enamel, although the subject mat- today.

REFERENCES ed., 2nd revised printing. Gemological Institute of Amer- Ashbee C.R., Transl. (19671The Treatises of Benvenuto Cellini ica, Santa Monica, CA. on Coldsmitlzing and . Dover Publications, New Lyon E. (1976)The trouble with treasure. National Geographic, York. Vol. 149, No. 6, pp. 786-809. Christie's (1988) Cold and Silver of the Atocha and the Santa Lyon E. (1982) Treasure from the ghost galleon. National Margarita (catalog].Auction June 14-15, 1988, New York, Geographic, Vol. 161, No. 2, pp. 228-243.

N- Y.-. Mathewson R.D. Ill (1986)Treasure of the Atocha. Pisces Books, Haywarcl J.F. (1976) Virtuoso . Rizzoli International New York, NY. Publications and Sotheby Parlze Bernet Publications, New Muller PE. (1972)Jewels in Spain, 1500-1800. Hispanic Society Jersey and New York, of America, New York. Jones J,, Ed. (1985) The Art of Precoliimbian Cold: The fan Sinlzanlzas J. (1981) Emerald and Otl~erBeryls. Chilton Book Mitchell Collection. Little, Brown & Co., Boston. Co., Radnor, PA. Kane R.E., Liddicoat R.T. Jr. (1985) The Biron hydrothermal Starr M., Morequ R., Friday C. (1985)Treasure hunt: Wrecks to synthetic emerald. Gems Gemology, Vol. 21, No. 3, pp. riches. Newsweek, August 5, pp. 18-20, 23. 156-1 70. Webster R. (1983) Gems, Their Sources, Descriptions and Keller EC. ( 19811 Emeralds from Colombia. Gems &> Cen~ology, Identification, 4th ed. Butterworths, London. Vol. 17, NO. 2, pp. 80-92. 2,300 emeralds salvaged from Spanish shipwreck (1986) Los Liddicoat R.T. (1989) Handbook of Gem Identification, 12th Angeles Times, May 30.

206 Treasures of the Atocha GEMS & GEMOLOGY Winter 1989 ZIRCON FROM THE HARTS RANGE, NORTHERN TERRITORY, AUSTRALIA By Maxwell Faulkner and Tames E. Shigley

Gem-quality zircon from a relatively un- long-known but underdeveloped locality in Austra- derdeveloped locality in the Harts Range A lia's Harts Range is now producing some magnificent of central Australia is described. While gem in an attractive variety of yellow, brown, pink, exhibiting many properties of other gem and purple colors (figure 1) in sizes typically of several zircons, this material is unusual in its carats. Occasionally, even near-colorless crystals are almost total lack of radioactive trace ele- found. Of particular significance is the fact that these inents. Thus, there is little or no radia- tion-relatedstructural damage as is the zircons contain little or no detectable amounts of radioac- case with softie other gem zircons. The tive trace elements. Thus they display no evidence of the Harts Rmge material occurs in a size, structural damage that is common in some gem zircons quality, and color range suitable for from other localities. This article briefly describes the faceting. geologic occurrence and gemological properties of these interesting zircons.

WHAT IS ZIRCON? Zircon is a widely distributed accessory in ig- neous rocks, particularly granites and syenites (Deer et al., 1982; Webster, 1983).It is a fairly common detrital mineral in some sediments due to its resistance to chemical attack. Zircon also occurs in certain metamorphic rocks such as , gneisses, and schists. While often found as small, ABOUT THE AUTHORS rounded grains, zircon can occur as large, well-formed Mr. Faulkner is a gem cutter from New South prismatic crystals. Because of its relatively high refractive Wales, Australia. Dr. Shigley is director of re- index, , and hardness, zircon has long been used search at the Gemological Institute of America, as a . Santa Monica, Calilornia. Chemically zircon is zirconium silicate (ZrSi04);how- Acknowledgments The authors thank Dr Elton L ever, there is always a small amount (usually about l %)of McCawley of Portland, Oregon, for his contnbu- lions to this study Waldo Winterburn, of Stanford the element hafnium present (Deer et al., 1982).A number University carried out the XRF and XRD analyses of trace elements can also occur in zircon, including John Kotvula of GIA documented the gemological uranium and thorium. When present, these two trace properties and took the photomicrographs Dr Emmanuel Fntsch of GIA assisted in the inter- elements undergo radioactive decay, thereby giving off pretation of the absorption spectra Bill Hagan of energetic alpha particles that can cause extensive struc- Rubyvale, Queensland, provided information on tural damage. As a result of this internal radiation bom- heat treatment Microprobe analyses were per- formed by Paul F HIava of Sandia National Labo- bardment, the initially crystalline zircon (referred to as rafones high zircon) progressively changes into an amorphous, Gems & Gemology, Vol. 25, No. 4, pp. 207-215 noncrystalline (ormetamict) state (lowzircon;see Holland 0 1990 Gemological Institute of America and Gottfried, 1955).Transition to the metamict condition

Zircon from Harts Range GEMS & GEMOLOGY Winter 1989 207 Figure 1. These faceted zir- cons from the Harts Range illustrate some of the at- tractive colors in which this material occurs. They range up to 5 ct in wei* Photo by Robert Weldon.

is accompanied by changes in physical and chemi- damage. Like most gem zircons, stones from the cal properties (such as a decrease in density, Harts Range belong to the high type. , and transparency, and an increase in water content). Thus, gemological properties LOCATION AND ACCESS such as refractive index or specific gravity can lie The Harts Range lies in the south-central portion anywhere between the values for high and low of the Northern Territory, toward the center of zircons (see table 1). Australia (see figure 2). The zircon occurs at a site While crystalline zircons occur in a range of aptly called Zircon Hill, which can be reached colors, metamict zircons are typically green or from the town of Alice Springs by driving 69 lzm brown. Some low and intermediate zircons can be (43 mi.)north on Stuart Highway, and then 77 lzm transformed back into high zircons by heating them (48 mi.) east on Plenty Highway. The turnoff from to 1450° for six hours (Chuboda and Stackelberg, Plenty Highway to the zircon deposit is marked by 1936))which heals the radiation-induced structural a large windmill and several concrete storage containers at a livestock watering station called Mud Tank Bore. From this turnoff, the last 9 km TABLE 1. The three types of zircon.3 (5.6 mi.) south to Zircon Hill is a gravel road, suitable for passenger cars. The digging area for Property Normal (High) Intermediate Metamict (Low) zircons is in open savannah country crossed by a Color Colorless, Brownish Green, orange, few dry stream beds. brown, green, green, brown yellow, red- brownish GEOLOGY brown, orange, red blue (heat The low-lying hills of the Harts Range extend east- treatment) west for approximately 150 lzm (93 mi.). They are Structural Crystalline, Slightly Amorphous, composed of schists, gneisses, and other strongly state undamaged damaged damaged metamorphosed sediments and volcanic rocks Refractive which have been intruded by occasional peg- indices 0 matite~(for details of the local geology, see Jolzlilz, â 1955).The area has long been known as a source of Birefringence mica, but it also contains numerous separate small Specific deposits of gem minerals such as , aqua- gravity marine, , and that have been Radioactivity Low Medium High mined sporadically in the past (see McColl and Warren, 1980). In addition, gem-quality iolite, "Properties compiled from Anderson (1941), Webster (1983), Liddicoal (1987). epidote, feldspar (called "rainbow lat- tice" sunstone in the trade), as well as kornerupine

208 Zircon from Harts Range GEMS & GEMOLOGY Winter 1989 Plenty Hwy. Figure 2. Zircon Hill is lo- cated in the Northern Terri- Mud Tank Bore tory of Australia, approx- imately 155 km by road northeast of Alice Springs. Neighboring Specimen Hill also produces zircons, but few are of gem quality Art- work by Jan Newell. \ L

and sapphirine (McColl and Warren, 1984) are phlogopite, magnetite altered to martite, and apa- found in small amounts. A guidebook to localities tite are present. in this area has been published by the Northern While there are many sites in Australia where Territory Department of Mines and Energy sediments rich in fine-grained zircons occur, the (Thompson, 1984). area around Zircon Hill produces the mineral in Brown et al. (1989) briefly describe the gem- large crystals. Zircons up to 2.5 kg (5.5 lbs.) have quality zircons that are found at Zircon Hill both been recovered from the decomposed carbonatite. as large crystals and crystal fragments. The entire Although these large crystals are invariably crest of the hill, a slight, brush-covered promi- cracked and flawed, they may contain small areas nence that rises some 50 m above the surrounding of material suitable for faceting. Much more com- plateau (which is 1,500 m above sea level), is mon are crystals or crystal fragments that range up covered by small diggings (figure 3).Zircon is also to several carats in weight. Only recently has the found at a nearby location called Specimen Hill, gem potential of this material begun to be recog- but these crystals, although better developed than nized (Brown et al., 19891. those from Zircon Hill, are generally unsuitable for faceting because of internal fracturing. Both MINING locations have been known by local miners and According to guidelines issued by the Department mineral collectors for about 40 years. of Mines and Energy, digging at these deposits can At these two localities, the zircon occurs in only be done with hand , and only after one carbonatite, a carbonate-rich magmatic igneous has obtained a prospecting license. Use of explo- rock that intruded the country rock to form a sives or mechanical equipment is prohibited. series of low hills. The carbonatite is late Pro- Hence, there has not been any large-scale mining terozoic, and has been age-dated between 1.50 and in this area. 1.78 billion years. In addition to calcite and zircon, On Zircon Hill and along a nearby creek bed,

Zircon from Harts Range GEMS & GEMOLOGY Winter 1989 209 zircon from other mineral and rock frogmen ts stands in the center of the photo- graph.

crystals and fragments are recovered by hand Some of this material may be enhanced by heat digging and dry sieving of the weathered soil that treatment. No accurate figures are available for the covers the carbonatite. Because of zircon's subada- quantity of zircon that has been recovered from mantine luster, the glistening but often highly this deposit thus far, nor has any estimate been fractured crystals and fragments are easily recog- made of possible reserves. However, the potential nized. After six hours of easy digging, about 0.5 kg seems quite good. (1 lb.) of mine-run zircons can usually be recov- ered. Pick-and-shovel mining of the underlying CHARACTERIZATION OF weathered but still intact carbonatite can yield HARTS RANGE ZIRCON zircon matrix specimens. For this study, we examined eight rough zircons As is usual for many gem mineral deposits, less and two faceted stones. The rough pieces weighed than 5% of the mine-run material is facet grade. between 6.6 and 37.1 ct (figure 4). With the exception of the largest sample, the rough pieces were rounded crystals or fragments. The largest Figure 4. These four of the eight rough zircons sample exhibited some crystal faces and a recog- examined for this study are representative of nizable tetragonal habit. Most of these specimens the material found at the Harts Range. The are light brownish purple, but orange-brown, yellow- largest specimen shown here weighs 19.1 ct. brown, and near-colorless zircons are also repre- Photo by Robert Weldon. sented. In the authors' experience, purple zircons are the most sought after from this locality (figure 5).The two cut stones examined for this study, one near colorless and the other a light orangy brown, weighed 8.03 and 4.44 ct, respectively (figure 6). Both the rough and faceted near-colorless samples had been heat treated. The gemological properties of these 10 samples are summarized in table 2 and discussed below (for comparison to gem zircons from other localities, see Webster, 1983, and Lid- dicoat, 1987).

Physical Properties. Using immersion oils and the Beclze line method, we found the refractive index to be above 1.81, a value consistent with that of intermediate or high zircons.

210 Zircon from Harts Range GEMS &. GEMOLOGY Winter 1989 Figure 5. This brownish purple zircon from the Figure 6. The study also included these two fac- Harts Range represents some of the best mate- eted zircons, which weigh 8.93 and 4.44 ct, re- rial from this area. The 35-ct stone was faceted spectively The near-colorless stone has been by Jennifer Try. Photo by Robert Weldon. heat treated. Photo by Robert Weldon.

Hydrostatic measurement of the specific gravity pie zircon are illustrated in figure 7. These two of four of the zircons yielded values between 4.62 spectra, recorded in orientations both parallel and and 4.72, which are also typical for high zircon. perpendicular to the optic axis, can be considered Brown et al. (1989) report the hardness of the as having four cofiponents: material to -be 7-7'12.

Absorption Spectrum. Many gem zircons exhibit a characteristic absorption spectrum that consists of numerous sharp bands of varying intensity. TABLE 2. Gemological properties of Harts Range zircon. Anderson (1956)lists more than 40 bands observed in high-type gem zircons, noting that the number, Color Pink, purple, yellow-brown, orangy intensity, and sharpness of the bands decreases in brown, near colorless, (produced by heating in a reducing atmosphere) the spectra of low-type zircons (see also Webster, Transparency Transparent 1983, pp. 155-156). Refractive index Above 1.81 (m= 1.923, e= 1.982; see When viewed with a hand-held spectroscope, Brown et al., 1989) the Harts Range zircons exhibited a relatively Specific gravity 4.62-4.72; average 4.65 small number of sharp absorption bands (all of Absorption spectrum Increasing absorption below 500 nm; (as seen with a possibly a weak, broad band at 535 which, however, are included in Anderson's list). hand spectroscope) nm; a weak but sharp band at 590 The 653-nm band was the most prominent, but nm; a strong, sharp band at 653 nm additional weak bands were seen at 535, 590, 657, (or a broad band from 650 to 653 and 689 nm in one or more of the samples. We nrn); and weak, sharp bands at 657 and 689 nrn found that the intensity of all these bands was U.V. fluorescence greater in zircons of lighter color, and greatest in Long wave Yellowish, brownish yellow, yellowish the near-colorless, heat-treated material. This con- orange; weak to strong in intensity; cloudy appearance; no firms the observations by Brown et al. (1989). phosphorescence We recorded room-temperature absorption spec- Short wave Yellow, brownish yellow, yellowish tra for all the zircons using a Pye-Unicam 8800 orange, often with zones that are UVIVIS spectrophotometer. There was little varia- bluish white; moderate to very strong in intensity; cloudy appearance; no tion among spectra except for the relative inten- phosphorescence sities of the features that can be correlated quali- Inclusions Tiny pinpoint inclusions; needle-like tatively with the depth of the body color and size of inclusions of an unknown mineral; partially healed fractures and the specimen. occasional cleavages Representative spectra of a light brownish pur-

Zircon from Harts Range GEMS & GEMOLOGY Winter 1989 211 1. Increasing absorption toward the ultraviolet, only in the spectrum recorded parallel to the giving rise to the brown component of the color, optic axis. which we believe results from a color center Spectra (recorded in a random optical orienta- that produces a very broad absorption band in tion) of the darker purple, yellow, brown, and near- the ultraviolet with an absorption "tail" that colorless zircons exhibited various combinations extends into the visible. of these same features. The weak sharp bands 2. A broad region of absorption centered at about attributed to uranium were present in each spec- 540 nm, giving rise to the pink-to-purple colora- trum but with slight variations in intensity. In an tion, and which we believe is due to a radiation- orange-brown sample, only the broad band in the induced color center, possibly involving rare- ultraviolet was present; the absence of the purple earth elements. The shape of this broad band is color coincided with the absence of the 540-nm different in the spectrum taken parallel to the broad band. A yellow zircon also displayed the optic axis as compared to the one taken perpen- broad band in the ultraviolet, but was missing the dicular to it, which is consistent with the slight 540-nm broad band. Finally, a near-colorless sam- brownish purple to purple dichroism observed ple had a very flat spectrum that nonetheless in this sample. exhibit a few of the same sharp bands caused by uranium. 3. A series of weak but sharp bands that have no influence on the color (sincethey are found even Ultraviolet Fluorescence. Zircon is known to vary in near-colorless samples), and are attributed to widely in both the color and intensity of its trace amounts of uranium (as U4+). Fielding reaction to U.V radiation (Webster, 1983). This is (1970)illustrated a spectrum with these same also the case for the Harts Range material. The sharp bands for a synthetic zircon doped only purple samples fluoresced a weak to moderate with about 10 ppm U4+. brownish yellow to both long- and short-wave U.V 4. A weak broad band centered at 760 nm present radiation; the yellow-brown, orange-brown, and

Figure 7. These absorp- tion spectra were re- corded both perpendicii- lar (top) and parallel (bottom) to the optic axis of a 37.1-ct brown- ish purple zircon crystal from the Harts Range.

I I I I I b 400 500 600 700 800 WAVELENGTH (nm)

212 Zircon from Harts Range GEMS & GEMOLOGY Winter 1989 TABLE 3. Microprobe chemical analyses of eight Harts Range zircons.a

Light Near Light Light Orangy Light Light purple Yellow colorless purple purple brown purple purple

33.03 32.41 32.45 32.57 32.56 32.36 0.01 0.01 0.01 0.01 0.01 0.02 66.70 66.58 66,29 66.45 66.58 66.14 0.10 ND 0.01 0.03 0.05 0.03 0.10 BDL ND ND 0.04 BDL ND 0.06 ND 0.02 0.03 BDL 1.31 1.48 1.50 1.44 1.37 1.49 101.25 100.55 100.26 100.52 100.64 100.04

'Figures based on an average of live point analyses ND = Not detected BDL = Measurement obtained at or below the reliable detection limits (approximately 10 ppm) of the equipment and operating conditions. Cameca MBX microprobe run a1 15 KeV and about 40 nanoamps; 100 second counting time; standards-Si, Zr (zircon), rare-earth elements (Drake Weill REE glass), Fe (), Ca (wollastonile), U (davidite), Th (Tho,), Ce (CeO,), Gd (gadolinium gallium garnet), Y (yttrium aluminum garnet), HI (pure metal) Complete analyses and further details of operating conditions are available on request to the authors. Analyst: Paul F. HIava "Other elements measured: Fe, Y, La, Ce, Th, U = ND -BDL, Pr S 100 ppm, Nd S 200 ppm, Sm 5 350 ppm, Eu 5 200 ppm, Gd < 250 ppm, Tb <. 200 ppm, Dy <. 250 ppm, Ho -5 150 ppm, Pb 5 100 ppm.

near-colorless zircons fluoresced a more intense sured reflections (for the brownish purple zircon yellow or yellowish orange color. No phosphores- that produced the absorption spectra shown in cence was noted for either long- or short-wave figure 7) yielded unit-cell dimensions of a = conditions. In all cases, the fluorescence was 6.603(4)A and c =' 5.983(5)A. These valuesare cloudy. In 'addition, zones (sometimes very con- nearly identical to those for an idealized zircon spicuous) of blue-to-white fluorescence could be (see Deer et al., 1982). seen in several of the samples during exposure to short-wave U.V radiation. Documentation of Radiation Level. Some gem zircons can be slightly radioactive due to their Chemical and X-ray Data. Qualitative chemical contents of uranium and thorium. Using a portable analyses using wavelength-dispersive X-ray fluo- Geiger-Muller detector (Technical Associates rescence were performed on samples of each color. Model 6A) attached to a scalerlcounter, we The presence of zirconium, hafnium, and iron was checked the radiation levels of each of the eight indicated, while the following elements were rough samples. To isolate the samples from back- checked for but not detected: uranium, thorium, ground radiation in the surrounding environment, yttrium, tin, arsenic, gallium, technetium, lead, we positioned both the sample and the detector niobium, and tantalum. inside a container of lead bricks. In each instance, The samples were also analyzed quantitatively the measured level was identical to the level of using a Cameca MBX electron microprobe (table3). natural background radiation. Under these same These results confirm the almost complete ab- testing conditions, several gem zircons from the sence of uranium and thorium. The concentration GIA collection display radiation levels slightly levels of uranium, which is indicated by the above background. Our results further substanti- presence of sharp U4^--relatedabsorption bands in ate the very low uranium and thorium contents of the spectrum, are too low to be detected by these zircons. microprobe analysis. It is interesting that no iron was detected during this analysis, which contrasts with the X-ray fluorescence data. Microscopy. The zircon samples we examined An X-ray diffraction pattern was prepared for were transparent with no hint of cloudiness except samples of each of the four colors using a Rigaku for a few local areas that contained small inclu- powder diffractometer. The resulting patterns are sions. In each sample, the color of the material consistent with the pattern of zircon illustrated in appeared to be evenly distributed. the 1986 JCPDS Powder Diffraction (pattern The two faceted stones did contain planes of tiny no. 6266). Least-squares refinement of 20 mea- inclusions along partially rehealed fractures (fig-

Zircon from Harts Range GEMS & GEMOLOGY Winter 1989 213 FACETING OF HARTS RANGE ZIRCON

To take best advantage of the optical properties of and in free wheel (if a standard brilliant or a zircon, the style and method of faceting is impor- round stone) proceeds to cut the outside to the tant. For the initial dopping, the senior author desired diameter. The table is cut and polished uses a wax developed by Heath Sabadina that is at 0Âor at 45' using a 45' dop. both tough and allows time for accurate center- All cutting is done first on a 1200-grit, then a ing. Sabadina wax is made by mixing green 3000-grit, lap; all polish is with either a ceramic Samson or Jewelers' Special wax with an equal or a tin lap. After the table is polished, the volume of flake orange shellac, heating the mix- protractor is set to a 40' angle to cut the eight ture to just below the boiling point, and then main facets of the crown; then the eight star pouring it into a large volume of cold water. The facets are cut at 24¡ The author rechecks the stone is usually oriented on the dop for maxi- accuracy of the main and star facets before mum weight recovery, since the pleochroism of proceeding to cut the 16 girdle facets. These these zircons is weak. However, some cutters do facets are then polished and the stone transferred orient it on an optic axis of the crystal to to a second dop using epoxy putty as an adhesive. minimize the double images of the pavilion facet After the epoxy putty is set hard (approximately junctions caused by birefringence. 20 minutes in sunlight), the first dop is removed The senior author roughly shapes the zircons either by heating the wax with an alcohol by hand on a 180-grit diamond-bonded lap (all of lamp or by means of blacksmith's pincers. his laps are either Crystalite Maja or glass). Then The author then proceeds to facet the pavilion he dops the stone with the Sabadina wax and with the common zircon-cut facets, making the locks the dop in the chuck of his Gemax faceting main facets 43O. After the crown has been com- machine. After setting the protractor angle to pleted, he sets the protractor to 88' and in free 90°he lowers the dopped stone to a 260-grit lap wheel polishes the area needed for the girdle.

ure 8). One of these stones also displayed a small Effects of Heating. Heat treatment has long been needle-like solid inclusion of unknown identity. used to transform reddish brown zircon into more Finally, when the faceted stones were examined marketable colorless, blue, or red material (for with magnification, the expected doubling of facet further details, see Webster, 1983, pp. 156-158; junctions was characteristically quite pro- Nassau, 1984, pp. 172-173; Brown et al., 1989). nounced. Brown et al. (1989) also reported (and Experiments performed over the last several years illustrated) small needle-like crystals thought to to study the reaction of Harts Range zircons to heat be apatite, brownish lath-like crystals of an un- treatment have demonstrated that these zircons known mineral, and rounded unknown crystals can be decolorized by heating to several hundred surrounded by a halo of tiny cracks. degrees Celsius in a reducing atmosphere for several hours. In fact, heat treatment of the Harts Range material can only produce near-colorless stones. The color in all Harts Range zircons can be Figure 8. At 5 x magnification, small inclusions were observed lying along partially rehealed restored by radiation treatment. Unless exposed to fractures in the faceted zircons studied. Photo- radiation, the near-colorless material produced by micrograph by John I. Koivula. heat treatment is stable. CONCLUSION An area of the Harts Range, Australia, is producing gem zircons in a range of attractive colors. Perhaps the most unusual feature of these zircons is that they contain very low quantities of radioactive trace elements. Thus, they exhibit no evidence of being or becoming metamict and, more impor- tantly, are not detectably radioactive. This locality is likely to be a commercial source of gem zircon as well as other gem materials in the future.

214 Zircon from Harts Range GEMS & GEMOLOGY Winter 1989 REFERENCES Anderson B.W 11941)The three zircons. The Gemmologist, Vol. Range, Central Australia. Bureau of Mineral Resources of 10, pp. 56-67. Australia Bulletin, Vol. 26. ~ndersonB.W (1956) The spectroscope and its application to Kremkow C. (1988) Cool zircon deposit found in Australia. gemmolorn part 32. The absorption spectrum of zircon. News Asia, No. 46, p. 32. The Gemmologist, Vol. 25, No. 297, pp. 61-66. Liddicoat R.T ]r. (19871 Handbook of Gem Identification, 12th Brown G., Bracewell H., Snow 1. (1989) Gems of the Mud Tank ed. Gemological Institute of America, Santa Monica, CA. carbonatites. Australian Gemmologist, Vol. 17, No. 2, pp. McColl D.H., Warren R.G. (1980) First discovery of ruby in 52-57. Australia. Mineralogical Record, Vol. 11, No. 6, pp. Chuboda K., Stackelberg M.V (19361 Dichte und Struktur des 371-375. Zirkons. Zeitschrift fin Kristallographie, Vol. 95, pp. ~cCollD., Warren G. (1984) Kornerupine and sapphirir~e 230-246. crystals from the Harts Range, Central Australia. Miner- Deer MA., Howie R.A., Zussman J. (1982) Rock-forming Min- alogical Record, Vol. 15, No. 2, pp. 99-101. erals, Vol. IA, Orthosiljcates, 2nd ed. Longman, London, Nassau K. (1984) Gemstone Enhancement. Butterworths, pp. 418-442. London. Fielding PE. (1970) Colour centres in zircon containiig both Thompson R. (1984) A Guide to Fossicking in the Northern EuJ+ and U4+ions. Australian Journal of Chemistry, Vol. Territory, 2nd eel. Northern Territory Department of 23, pp. 1513-1521. Mines and Energy, Darwin. Holland H.D., Gottfried D. (19551The effect of nuclear radiation Webster R. (19831 Gems: Their Sources, Descriptions and on the structure of zircon. Acta Crystallographica, Vol. 8, Identification, 4th ed. Revised by B. W Anderson, Butter- PP. 291-300. worths, London, pp. 153-160. ~ok1ikG.F.0955) The Geology and Mica-Fields of the Harts

VOTE OR THE Gl%hfSâ‚ GEMOLOGY &@T VALUABLE ARTICLE AWARD AND WIN

Zircon from Harts Range GEMS & GEMOLOGY Winter 1989 215 BLUE PECTOLITE FROM THE DOMINICAN REPUBLIC By Robert E. Woodruff and Emmanuel Fritsch

Blue pectolite from the Dominican Re- he Dominican Republic is perhaps best known to public, also known by the trade name Tgemologists as an important source of and Larimar, has recently entered the U.S. conch "pearls." Since 1986, however, it has gained recogni- market. Large quantities of this attractive tion as the source of a relatively new gem material, blue ornamental stone have been found in cav- ities and veins of altered . Most of pectolite. Although actively mined since about 1974, blue the gemologiccil properties are consistent pectolite has recently benefited from greater availability with those previously reported for pec- and broader distribution (Koivula and Misiorowski, tolite; the cause of color in this material 1986a). Previously, gem pectolite occurred only in an is believed to be related to the presence of unattractive white to gray color and was considered rare small amounts of Cu2+. The color ap- because of its scarcity in pieces suitable for cutting pears to be stable to light, but does react (Webster, 1983; Liddicoat, 1976). The new and more to irradiation and to the heat of a jewel- plentiful supply of blue, and less commonly green, pec- er's torch. It is easily separated from simi- tolite has helped it achieve recognition as an excellent lar-appearing materials. material (figure 1); carvings are now on display in the Smithsonian Institution and the Lizzadro Museum [Lizzadro, 1987). The first mention of this material in the gemological ABOUT THE AUTHORS literature was by Arem (1977).Although he does not list Dr. Woodruff, a professional entomologist who has blue under the possible colors of pectolite, he includes a studied insect inclusions in amber, is the owner of photograph of some Larimar cabochons. More recently, Woodruff's Gems, Gainesville, Florida. He has been involved in the marketing of pectolite since two articles have appeared in the lapidary and consumer 1975 and has made numerous trips to the mine. literature (Woodruff, 1986, 1987). The present article Dr. Fritsch is research scientist at the Gemologi- reviews the deposit where this material is found, its cal Institute of America, Santa Monica, California. history, location, and geology. Also examined are the Acknowledgments: The authors thank Ramon Ortiz for his hospitality and contributions to this gemological properties of pectolite, including chemistry, study. Jake and Marianella Brodzinsky provided cause of color, and reaction to treatment. housing and technical assistance in the Domini- can Republic. Samples and information were also LOCATION AND ACCESS provided by Charles Mark, of Mountain-Mark Trad- ing Ltd. Dr. James Shigley provided helpful sug- The Dominican Republic occupies the eastern portion of gestions. Waldo Winterburn and Dr. Julie Paque, the island of Hispaniola (figure 2). The blue pectolite is of Stanford University, did the wavelength-disper- sive XRF and microprobe analyses respectively. found approximately 170 lzm southwest of the capital, C. W. Fryer obtained the X-ray diffraction patterns. Santo Domingo (Ciudad Trujillo), just west of Baoruco, a Skip Franklin prepared many of the samples for small village south-southwest of Barahona in the province spectroscopic studies. Dr. George Rossman, of the California Institute of Technology, helped with of the same name. The climate is tropical and the vegeta- the irradiation experiment. tion luxuriant. Waterworn fragments of pectolite were first Gems & Gemology, Vol. 25, No. 4, pp. 216-225 found in the alluvials of the Rio Baoruco and later traced to 0 1990 Gemological Institute of America their in-situ source upstream.

216 Blue Pectolite GEMS & GEMOLOGY Winter 1989 Figure 1. The 26 x 14 mm- cabochon of fine blue pec- tolite in this silver ring is from the Dominican Repub- lic. Behind it is an excellent example of some of the best rough material. Photo by Kris Illenberger; courtesy of Mountain-Mark Trading Ltd.

The actual deposit is located on the road to the sole supplier to the domestic trade. According Filipinas in an area lznown as Los Checheses (two to Luis Augusto Gonzales Vega, lawyer and owner localities so small that they do not appear on local of property on which a portion of the deposit maps). The entrance to this road is about 3 lzm occurs, he and Mendez formed a corporation to north of Baoruco. Dirt roads lead to the mine, but mine and market pectolite. The original docu- four-wheel drive vehicles are needed to negotiate ments of this venture give the trade name Trav- the last few kilometers of the journey. The area is elina, but this was later changed to Larimar, coined accessible all year round. by Mendez from his daughter's nickname Lari The pectolite is found in various portions of a combined with the Spanish word for sea, mar. This single volcanic deposit approximately 0.15 lzm2 in trade name has been used consistently since 1975, surface area. The Rio Sitio, a small stream that although neither Gonzales Vega nor Mendez is drains into the Rio Baoruco, was probably the currently involved in the marketing of this mate- carrier of those tumbled pieces first found at rial. Baoruco. All mineral rights in the Dominican Republic belong to the government, and pectolite mining is HISTORY permitted only by concession from the Mineria, In 1974, Norman Rilling, a Peace Corps volunteer, the Dominican Bureau of Mines. By 1985, nearly reportedly found some blue stones at Baoruco that 100 miners were working the deposit. To avoid were later identified as pectolite (Woodruff, 1986). confusion, overlapping claims, and disputes, the By 1975, specimens had already appeared in Mineria suggested that the miners form a coopera- jewelry shops in Santo Domingo. Many unverified tive and sell Larimar only from a small outlet in stories exist about the find and subsequent devel- the town of Baoruco. After the cooperative was opments (Woodruff, 1986), but it is known that formed, Ramon Ortiz of Puerto Plata purchased Miguel Mendez, a local resident, originally was the eastern part of the deposit and obtained a 10-

Blue Pectolite GEMS & GEMOLOGY Winter 1989 217 Figure 2. Blue pectolite is found in a basalt intrusion (green urea) that ex- tends inword from the villoge of BOO~LJCO,ill the province of Bar- ahona, Dominican Republic. Art- worli by Ian Alewell.

year mining concession. His miners and those of collected in the bed of the Rio Baorucol where it the cooperative worlz side-by-side. Currentlx as was originally discoveredJ are mostly smalll tum- many as 150 miners are involved on an irregular bled piecesl although some are of excellent quality. basis. Pectolite inay be purchased either at the The Barahona peninsula extends south of a mine-from the cooperative or from Ortiz- or at major west-east depression containing Lalze Enri- the cooperative building in the village of Baoruco. quill0 [approximately 40 m below sea level). This peninsula is composed of Tertiary limestones GEOLOGY AND OCCURRENCE (Oligocene to Miocene), with a few enclaves of The commercial quantities of blue pectolite avail- Upper Cretaceous volcanic roclzs described as able today are all mined at the primary deposit in and [Zoppis de Sena, 1969).The the mo~intainsabove Baoruco. The few stones main basalt intrusionJ in which the pectolite is

Figure 3. This exceptionally large [about 20 cm) slice of ' a pectolite vein shows the miner01 ond color zonotion typical of this gem mote- rial. 1Vatroljte (light gray) and chalcocite {black) crys- tallize, for the most port, on the wolls of the vein. In this sample, they are jollowed by red sprays ("plumes") of hemotjte crystols inter- grown with several genera- tions of blm pectolite of different color intensity ond tronsporency Fibrous color- less pectolite and white cal- cite fill the center. Photo by Rober~Weldon.

218 ~luePectolite GEMS & GEMOLOGY Winter 1989 found) extends from the coast inward at the lati- tude of the village of Baoruco (again) see figure 2). The volcanic roclzs have been intensely weathered and for the most part are altered to fine-grained serpentine. The only recognizable mineral visible in thin sections of the basalt matrix is clinopyrox- ene in small twinned crystals. Indications of copper, especially chalcocitel have been reported in these basalts (Va~~ghanet al.) 1921). Blue pectolite occurs as a hydrothermal mineral in cavities and veins in the altered basalt, This is the typical occurrence for the white to gray material) as already noted for pectolite deposits in Italy, Scotlandl and the United States (Webster, 1983). Sprays of elongated natrolite crystals are Figure 4. This 17-cm slab of fossilized sometimes present on the walls along which found at the mine shows blue pectolite between pectolite crystallizes in finely fibrous spherulites the rings, (figure3). No other zeolites have yet been fo~lndin this deposit. Colorless calcite is also commonly MINING associated with the bl~lepectolite in these veins, Most mining is open pit, with miners using only Rarely, crystals and small amounts of piclzl shovell and to brealz the weathered white pumice are found as well, basalt in search of pectolite. Until recently, the pits The blue pectolite does not occur system- averaged 1 m acros's and were no deeper than 10 m. atically; gei~erallythe veins are found under an The heavy rainfall common to this area floods the ~~~perinostgayer of altered basalt that contains red pits periodically, so mining is intermittent. The hematite. These veins may disappear or enlarge recent acquisition of a scraper and ;I pump has very suddenly (unlilze the system of fractures res~lltedin a number of pits that are larger (as associated with pegmatite veinsl for example). much as 10 m in diameter] and deeper (as m~lchas Petrified) carbonized logs are found embedded in 25 m) than average (fig~lre5). This acquisition the altered basalt. Rarely, some logs even exhibit a coincided with the developinent of the western filling of blue pectolite in fractures between the area of the deposit. The fine bl~~eof the gem- rings of the wood (figure 4). q~~alitymaterial found in this newer area coi1trasts

Figure 5. Although much of the orea is marked by smoll pits dug by hand, the newly developed port o\ the mine uses more sophis~cuted equipment and techniques to excavate deeper, lurger pits in the weathered basalt t11at hosts the blue pec- tolite. Photo by Richard Barrett; courtesy of MOIIII- tain-Mork Tradil~gLtd,

Blue Pectolite GEMS & GEMOLOGY Winter 1989 219 1.59-1.63 for this polycrystalline material. This corresponds to that reported for pure pectolite (Deer et ale!1978). Less accurate measurements by the spot method ranged from 1-57to 1.63! with the variations due to different contents of iron and manganese (Arem! 1977; Schmetzer, 1984).

Specific Gravity. Measurements obtained by the hydrostatic method on five of the sample stones varied from 2.62 for the green material to 2.87 for a fine! homogeneous blue cabochon. A specimen with numerous chalcocite inclusions showed an S.G. of 2.90. These val~~esare consistent with measurements of 2.84-2.90 reported by Deer et al. Figure 6, A striking contrast is seen between (1978) and 2.74-2.90 by Schmetzer (1984).Note this fine blue pectolite (15 x 21 mm) found in that the green pectolite with the lowest S.G.! 2.62! 1987 and a green cabochon (18 x 25 mm) with in our sample group contained numerous natrolite considerable matrix and natrolite inclusjons inclusions (S.G. of 2.20-2.25). found in 1975, The stone on the left is represen- tative of the finest color found to date. Photo Hardness and Toughness. Scratch tests on freshly by Robert Weldon. mined material suggest a Mohs hardness of some- what over 5 to as much as 6 for finely fibrous! inarlzedly with the poorer quality green stones compact material, Although the boolz value for (figure 6)originally found in the mouth of the Rio pectolite is 4lh-5 (Roberts et al.! 1974; Deer et al.! Baoruco, Many miners worlz only when they are 1978)) fibrous types may be expected to have a not picking coffee-which is harvested from No- higher value as well as greater to~~ghnessthan their vember to February- or fishing. moi~ocrystallinecounterpartsl because each grain boundary forms a barrier to the propagation of GEMOLOGICAL PROPERTIES microfractures induced by the scratch (Fritsch and Six samples of Larimar were tested by X-ray Misiorowslzil 1987; M. Gardos, pers. comm.l 1989). powder diffraction to confirm their identity as The toughness of blue pectolite is excellent) al- pectolite! NaCa2Si308(OH).While pectolite is de- though pieces less than 2 mm in thiclzness may composed and gelatinized by HCl [Deer et al.) tend to flalze, Carvers report that they worlz this 1978)/ it does not effervesce to the standard 10% material using methods and agents similar to solution commonly used in testing [Liddicoat) those ~isedto carve jadeite. Lilze jadeitel pectolite 1988); if effervescence occursJ it is due to the also talzes an excellent polish. presence of calcite inclusions. Visually, blue pectolite displays finely fibrous Fluorescence. More than 20 specimens of blue and spheroidal aggregates in polished slabs or cab- green! rough and cut) pectolite were examined for ochons; some pieces show patches of what appears their reaction to long- and short-wave radiation. to be chatoyancy. The range of color is similar to The blue pectolite exhibited a moderate) zoned that of (figure 7)! although most valued fluorescence to long-wave U.Y A very challzy green are the few darlzer specimens that resemble chrys- us~iallypredominatedl wit11 some zones more ocolla. White calcite veinlets between the spher- yellow and others almost blue. Fluorescence was ules are commonJ and hematite inclusions form wealzer in areas of very deep blue as compared to fern-lilze patterns in some pieces that are referred those with the fibro~~swhitish material. The green to as "red plume." Homogeneous pieces of ro~~gh pectolite fluoresced yellow to long-wave U,Y seldom exceed 10 cm. Fluorescence to short-wave U.Y of both colors of pectolite was m~ichmore homogeneo~is and Index of Refraction. We meas~~redR.I. on a flatl slightly more intense; the color was a very turbid well-polished surface of each of 12 samples of blue green. Sinlzanlzas (1964) reported that pectolite and green pect01ite~ and determined a range of fluoresces orange to short-wave U.Y; we presume

220 Blue Pectolite GEMS & GEMOLOGY Winter 1989 Figure 7. The different col- ors of Larjinar are similar to that of t~irq~zoise.These reference stones, all about 16 x 11 mm, ill~istratethe general grading system used for the vario~isqualities of pectolite: good blue (top left) to green (bottom, mid- dle) and "red plume" (mid- dle right). Stones courtesy of Mountain-Mark trading Ltd.; plloto by Robert Weldon.

that this is due to the high manganese content of pectolite was determined with an electron micro- the gray to white varieties then lznown. probe [Joel733 Superprobe), The resultsl shown in table 1) are similar to those p~iblishedpreviously Inclusions. Red dendrites! identified by X-ray dif- for pectolite from other localities (Deer et al., fraction &s' hematite! create distinctive fern-lilze 1978). The presence of manganese is not surpris- patternsnihtheso-called ''red plumeJ!variety; most ing! as it is lznown to substitute easily for such dendrites appear in outer portions of the pectolite feins (again! see figure 3). The carver of the elephant in figure 8 took advantage of such Figure 8. In these two blue pectolite carvings patterns to create a drapery effect on the baclz of prod~icedin Thailand, he carver has used the the beast. Hematite is ab~indantin the altered "red plume" layer to mimic a drapery on the el. basalt just above the pectolite-bearing veins. ephont's back and the sheen of the fibrous pec- More common are white to gray squarish tolite to suggest the catk fur. The elephant is patches of calcite that may be as large as 2 mm in approximately 5 cm high x 5 cm along its maximum dimension (figure 9). Calcite also oc- hose. Photo by Robert Weldon. curs as submicroscopic crystals between the ends of the pectolite fibers. Natrolite! another common inclusionl appears as transparent light gray sprays of elongated square crystals in the pectolite. When a cabochon is cut perpendicular to the main orientation of a natrolite sprax the surface is marked by shallow undercut pits of square or lozenge shape. Chalcocite forms clusters of microscopic blaclz flalzes (again see figlire 9) and sometimes adopts euhedral form (figlire 10); material that is heavily included with chalcocite is not used for gem purposes. Rarely, native copper may be present! ~isuallyfairly close to the wall of the vein, CHEMISTRY AND CAUSE OF COLOR The chemical composition of three samples of blue

Blue Pectolite GEMS & GEMOLOGY Winter 1989 221 Figure 9, These sq~iarish,slightly fibrous light gray inclusions me calcite crystals. Micxoscopic flalzes of black chalcocite sometimes lorn1 "blaclz eyes" (bottom left) in blue pectolite. Figure 10. Rarelx minute euhedral monoclinic Photomicrograph by Joh11 I. Koivula; magnified 10 x . crystals of chalcocite are scattered in the blue pectolite. The presence of this copper sulphide strongly suggests that the color is related to in the crystal structure (in fact! pectolite forms an traces of CLI.Photomicrograph by 1011n I. IZoi- isostructural series with serandite) the manganese vula; magnified 2 x . analogue of pectolite; see Deer et al.) 1978). The copper contentl too low to be determined accurately with the electron microprobel was ob- Similar features were observed in the optical tained by means of wavelength-dispersive X-ray absorption spectra of all six blue pectolite slices fluorescence (WDXRF)using a Rigalzu spectrome- examined using a Pye Unicam 8800 spec- ter. Three measurementsJ in different areas of a tropl~otometer(figure 11). A strong absorption in single sample of good colorl gave a remarlzably the ultraviolet decreases toward the red end of the homogeneous con cent ratio^^ of 46 to 47 ppm visible spectrum) except for a very broad, asym- copper. metric absorption band centered at approximately 630 to 650 nm in the red. This creates a transmis- sion "window" in the blue at around 480 nm! from TABLE 1. Chemical composition of light blue and which the blue color of the pectolite is derived. dark blue pectolite from the Dominican Repub1ic.a The spectrum of the rarer green variety (two specimens studied) is similar to that of the blue Oxide Light blue Dark blue specimens (againl see figure 11). However) the MnO absorption centered in the ultraviolet expands Fe 0 about 80 nm further into the visible. A wealzl very Si02 broad band centered at around 470-475 nm is A1203 present on its slope. Both features are apparently CaO responsible for shifting the transmission window MgO from 480 to approximately 510 nml which ex- cuo Ti02 plains the green color of this material. More detailed chemical and spectroscopic data are nec- cr203 Na20 essary to interpret those relatively minor varia- '2O5 tions. K20 These pectolite spectra are reminiscent of those of turquoisel which might suggest that the two Total 97.61 96.95 materials have the same coloring agent (Koivula =Microprobe analyses performed at the Center fo? Idaterials Research, and Misiorowsl~i~1986b). However! turquoise con- Stanford Un~versity,by Dr. Julie Paque, The total composition does not tains copper as a major constituentl while it is equal 100% because water, a component of pectolite, cannot be measured )with an electron microprobe, The range of water present only as traces in pectolite. The occurrence con cent ratio,^ measured in pectolite is 2,25% to 4.08% (Deer et el., of copper in silicate minerals is rather unusuall and 1978). bnd= not detected. there is little research available on this coloring mechanism (Gordon Brown! pers. comm.! 1986).

222 Blue Pectolite GEMS & GEMOLOGY Winter 1989 We do lznow that the absorption coefficient of the main copper absorption in the red is 373 to 691 mol-1 cm-1, assuming a homogeneous copper concentration of 50 ppm. This contrasts sharply with values of 6 to 40 mol- 1 cm-1 for coloration due to isolated Cu2+ ions (Lehmann, 1978; Ross- man 1988). This, along with other technical argu- ments, suggests that the absorption might be due to processes involving multiple atoms, probably within small clusters of Cu^ ions. Even for a small overall concentration, such processes may absorb light efficiently enough to produce the depth of color seen in fine blue pectolite. However, the details of the electronic transitions involved are not known at present.

COLOR STABILITY To test for color stability, we cut a specimen of blue Figure 12. The left part of this pectolite slice was submitted to a jeweler's torch for a few sec- pectolite into two parts and exposed one to light at onds, while the right section remained A- the end of a FiberLite for more than 50 hours. No touched. The heated section shows a loss of noticeable difference in color was observed when color and transparency that is due in part to this specimen was compared to the unexposed the development of 'small fractures which also control. * reduce the toughness of the specimen. Photo by Robert Weldon.

Figure 11. The optical absorption spectra of blue and green pectolite show an increasing ab- TREATMENT sorption toward the ultraviolet and a broad, We do not lznow of any effort to commercially asymmetrical band centered at around 645 nm, enhance blue pectolite. Rumors in the Dominican which is attributed to trace amounts of copper. Republic about dyeing low-quality material with a The position of the resulting transmission win- copper sulphate could not be substantiated, and we dow (480 nm for the blue and 510 nm for the green) accounts for the color. Artwork by Ian have no direct evidence that such a treatment has Newell. been performed. We submitted a slab of blue pectolite to a dose of 16 Mrads using Cs-137 gamma rays. Irradiated in this , the specimen turned mostly violet, although small blue spots remained and the white areas (calcite)turned brown. The violet coloration

is thought to be due to the formation of Mn3 + by irradiation of Mi++, which is present in trace amounts in blue pectolite (again, see table 1). For

further discussion of Mn3 + as a coloring agent, see Fritsch and Rossman (1988). When exposed to the flame of a jeweler's torch, pectolite tends to get whiter as a result of the propagation of small cracks (see figure 12). Also, some transparency is lost in the process. However, \ , no noticeable change in color or transparency was 300 400 500 600 700 800 observed in a thin slab of blue pectolite that was WAVELENGTH (nm) heated in an oven to approximately 300° for 10 hours.

Blue Pectolite GEMS & GEMOLOGY Winter 1989 223 Figure 13. Blue pectolite is used in virtually any type of jewelry as well as in carvings. Photo by Jeff Lotz.

SEPARATION FROM discovered, production has been extremely erratic. OTHER MATERIALS No exact figures are available, although Ramon Because of blue pectolite's distinctive appearance, Ortiz estimates that 2,500 kg were removed in only a few materials are likely to be mistaken for 1975, and 300-500 kg per week in early 1987. it. "Victoria stone," a devitrified man-made glass, Unfortunately, no records have been kept, so it is shows a fibrous structure similar to that observed difficult to estimate the volume and quality of the in high-quality pectolite. However, the fibrous material produced between 1975 and 1987. In aggregates in pectolite are much smaller and more 1988, Ortiz reports, he had almost no production, irregular, and none of the colors in which "Victoria and he believes that the cooperative also encoun- stone" is produced actually matches those of tered little material. In mid-December 1989, how- Dominican pectolite. Recently, GI&s Technical ever, four major veins of good-quality material Development Department noted the similarity of were found in the western part of the deposit, Larimar to "Imori stone," a partially devitrified which is being worked by the cooperative (C. glass (manufactured in Japan) into which fibrous Mark, pers. comm., 1989). There are no firm inclusions are induced to give it an overall fibrous estimates of future reserves. appearance. However, the vividness and homoge- The material produced varies greatly in quality. neity of "Imori stone's" color, as well as the Buying rough is considered a loteria (lottery) perfection of its fiber bundles, makes its separation because the pectolite is difficult to grade without from pectolite relatively easy. cutting. Ortiz estimates that about 20% is cut- Although the best blue pectolite (figure 6) may table, but only 5% is truly gem quality. The resemble -stained chalcedony, fine pec- presence of matrix and fractures further limits the tolite has a higher R.I. (1.59-1.63 versus 1.46-1.57) usefulness of the material. and S.G. (2.87 versus 2.24 or lower). A simple grading system has been developed by one entrepreneur to help communicate with his PRODUCTION AND DISTRIBUTION customers (again, see figure 6). It is based on the Since this deposit of blue pectolite was first relative proportion of blue, white, and green (in

224 Blue Pectolite GEMS & GEMOLOGY Winter 1989 order of decreasing value) in a particular piece and Arem J. (1977) Color Encyclopedia of , 1st ed. Van Nostrand Reinhold, New York. the presence or absence of "red plume." Although a Deer W.A., Howie R.A., Ziisstnan j. (1978) Rock Forming large lapidary market has yet to develop because of Minerals. Vol. 2A: Single Chain Silicates, 2nd ed. Halsted the limited availability of raw material, several Press and john Wiley &. Sons, New York. Fritsch E., Misiorowski E.B. (1987)The history and gemology of dealers were selling the material at the 1989 Queen conch "pearls." Gems d Gemology, Vol. 23, No. 4, Tucson Gem and Mineral Show. Larimar is also pp. 209-221. one of the few gemstones to be trademarked in the Fritsch E., Rossman G.R. (1988) An update on color in gems. Part 3: Colors caused by band gaps and physical phenom- U.S., with the moniker "Gemstone of the Carib- ena. Gems d Gemology, Vol. 24, No. 2, pp. 81-103. bean." Koivula J.I., Misiorowski E.B. (1986a) Gem News: Pectolite. Blue pectolite is used in many types of jewelry, Gems &> Gemology, Vol. 22, No. 2, p. 114. from rings and to bola ties (figure 13). Koivula J.I., Misiorowski E.B. (1986b) Gem News: Pectolite. Gems a) Gemology, Vol. 22, No. 3, pp. 187-188. One style typical of pectolite jewelry manufac- Lehmann G. (1978) Farben von Mineralien und ihre Ursachen. tured in the Dominican Republic is a silver neck- Fortschritte der Mineralogie, Vol. 56, No. 2, pp. 172-252. Lidclicoat R.T. jr. (1976)Developments and highlights at GINS lace combining Larimar cabochons with white lab in Los Angeles. Gems <&> Gemology, Vol. 15, No. 5, p. boar's tusk ("Amber . . .," 1978).A market 138. has also developed with "New Age" initiates, who Liddicoat R.T. Jr. (1987)Handbook of Gem Identification, 12th ed. Cen~ologicalInstitute of America, Santa Monica, CA. appreciate blue pectolite in various nonstandard Lizzadro J. (1987) The interesting story of a new blue gem products, such as meditation wands and even as material called Larimar. Lizzadro Museum, Summer-Fall, pebbles. pp. 13-14. Roberts W.L., Rapp C.R., Weber j. (1974) Encyclopedia of Minerals. Van Nostrand Reinhold, New York. CONCLUSION Rossman G.R. (1988)Optical spectroscopy. In F. C. Hawthorne, Although relatively little has been written on blue Ed., Reviews in Mineralogy, Vol. 18: Spectroscopic Methods in Mineralogy and Geology, Mineralogical Soci- pectolite from the Dominican Republic, this new ety of America, Washington, DC, pp. 207-254. gem material has become a familiar item on the Schmetzer K. (1984) Pektolith aus der Don~inikanischenRe- U.S. colore'd stone market. Production remains, publilc. Zeilschrift der Deiitschen Gein~nologischenGes- ellschaft, Vol. 33, No.1-2, pp. 63-64. however, unpredictable, and much of what we see Sinkankas J. (1964) Mineralogy Van Nostrand Reinhold, New on the market today was cut from material found York. some years ago. An organized effort is needed to Vaughan T.W., Cooke W., Condit D.D., Ross C.l?, Woodring W.P, Calkins F.C. (1921) A Geological Reconnaissance of the understand the geology of the deposit and the Dominican Republic. Official Publication of the Secre- distribution of the pectolite veins so that the taryship of State of Fomento and Communications, Wash- commercial potential of this material can be ington, DC. Webster R. (1983) Gems. Their sources, descriptions and better evaluated. identification, 4th ed. Revised by B. W. Anderson. Butter- worths, London. Woodruff R.E. (1986) Larimar, beautiful, blue and baffling. Lapidary Iournal, Vol. 39, No. 10, pp. 26-32. REFERENCES Woodruff R.E. (1987)The new Caribbean gem. Aboard, Vol. 11, No. 2, pp. 6-7, 35, 58-59. Amber and Larimar (1978)The Great Escape, Vol. 2, No. 16, pp. Zoppis de Sena R. (1969)Atlas geologico y mineralogico de la 6-9. Republica Dominicana. [No publisher noted.]

Blue Pectolite GEMS & GEMOLOGY Winter 1989 225 NOTES AND NEW TECHNIQUES

REFLECTANCE INFRARED SPECTROSCOPY IN GEMOLOGY By F. Martin, H. Mkrigoux, and I? Zecchini

External reflectance infrared spectroscopy permits a sically, reflectance spectroscopy measures the vi- very rapid and nondestructive determination of the bration energy of the atoms inside the crystals. species of a mineral. It is particularly useful with Inasmuch as these energies vary from one gem polished gems in that it requires no more than plac- material to another, the reflectance spectrum ing the stone, loose or mounted, on a reflection de- serves as a "fingerprint" of the stone. This allows vice in the infrared spectrometer and observing the identification of the mineral species and, in some recorded spectrum. Therefore, compared to the classi- cal methods of physical measurement such as refrac- cases, determination as to whether the stone is tive index, specific gravity, and the like, reflectance natural or synthetic. spectroscopy provides a much faster means of estab- The measurements for reflectance spectros- lishing the species of the gem and, in some cases, copy are much easier than for most other sophisti- whether it is natural or synthetic. cated techniques. Because a gem-whether mounted or loose-generally has at least one polished face, it need only be placed on the reflec- tance device in the spectrometer to obtain the spectrum. No elaborate sample preparation is Gem identification requires broad knowledge required, and the method is completely non- built on a number of observations. Generally, the destructive. Results can be obtained in a few identity of a gem material can be easily deter- minutes. mined on the basis of physical and optical proper- This article presents a general application of ties such as specific gravity, refractive index, and reflectance infrared spectroscopy to identify a cut visible-light absorption spectrum. In some cases, stone, with sample spectra provided for more than however, such as the separation of scapolite from 60 natural gemstones, synthetics, and simulants (figure l),more sophisticated methods may be required. X-ray diffraction and microprobe an- alyses have been used for this purpose, but they require very special equipment and sample prepa- ABOUT THE AUTHORS ration (which may be destructive). Mr. Martin is a research scientist. Professor Zecchin~is a co- External reflection infrared spectroscopy worker ol Professor Merigoux, who is director ol the Crystal- (commonlyreferred to as reflectance spectroscopy) lography Laboratory of the University 01 Franche-Comt6, lo- cated in eastern France. provides an intermediate solution for these prob- Acknowledgments: Mr. J P. Poirot, 01 the Chamber of Com- lem cases. It has been used in mineralogy for many merce 01 Paris, kindly loaned us almost all of the samples used years to measure optical constants such as refrac- for this study. tive index (Simon, 1951) and to determine funda- Gems & Gemology, Vol. 25, No. 4, pp. 226-231 mental vibrations of crystals (Simon, 1953). Ba- 0 1990 Gemological Institute 01 America

226 Notes and New Techniques GEMS & GEMOLOGY Winter 1989 (some of which were first reported by Leung et al., 1982; Ramirez et al., 1983, 1985; Zecchini, 1986; Zecchini et al., 1986, 1987).

INSTRUMENTATION AND EXPERIMENTAL PROCEDURES For this study, we used Perlzin-Elmer instrumenta- tion: two conventional grating infrared spectrome- ters, PE 580 B and PE 983, connected to PE 3600 data stations [which enabled us to record the spectra and provide graphic representation of the data) and the reflectance accessory illustrated in figure 2. This accessory is readily available from most infrared spectrometer accessory manufac- turers. For a given crystal, two types of infrared spectra can be recorded: a transmission spectrum (from which, if the sample is "transparent" to the infrared beam, an absorption spectrum can be derived) and a "mirror-like" (or specular) reflection spectrum correlated to the lattice vibrations of the crystal. According to observations made on the Figure 1. The separation of scapolite (right and infrared spectra of gem crystals, the fundamental bottom) and q~zartz(top and left), may be difficult to vibration energies of atoms in crystals are situated perform using standard gemological testing but is in the infrared don~ain,typically between 1500 accomplished in a matter of minutes with reflectance infrared spectroscopy Photo C3 Tino Hammid. cm - 1 (6600 nm) and 100 cm - 1 (100,000 nm), so reflection spectra can be observed only in this region. scattering dispersion is minimized, which is very The transmission method would be very pow- difficult with most dispersive infrared spectrome- erful if it were feasible to cut the stone; observa- ters. tions through a thin [few microns thick) slab give, Reflectance is much easier to perform: Simply directly, very accurate results on real lattice vibra- place a facet of the polished gem on the reflection tion absorption positions. Such exact positions, device. Because the observed bands are very spe- which are not necessary for our purpose, can be cific to a given crystal, the identification is easily calculated from the reflection spectrum [Laroussi, made by comparing the spectrum obtained with 1984).Although direct observation through a fac- prerecorded spectra for various gem materials. eted stone is sometimes possible, the transmission spectrum from such thicker materials does not TESTING AND RESULTS show the fundamental crystal lattice vibrations To determine the usefulness of this technique for (i.e., there is almost total absorption in that range), gem identification, we obtained infrared spectra, but rather only reveals the typical impurities such using reflectance spectroscopy, on more than 60 as water, carbon dioxide, nitrogen, hydroxide, and natural and synthetic gem materials. We studied at the like. Moreover, the stone must be placed in least five samples of each gem, and found that front of the incident beam in such a way that light- within the same mineral species, the variations between spectra for different varieties or from different localities are very small. Time varies according to the spectrometer used and the The reflectance spectrum of a pyrope garnet is observable surface of the sample. With a conventional gist- i11g spectrometer and an observable surface lawthan shown in figure 3 both in a conventional manner, a about 2 mm2, it ti~kesno longer than five minutes. If an continuous line that rises and falls with the FTfR spectrometer is used, even less time should be needed. reflectance of the sample, and converted to a set of For smaller samples, additional time is often required for placement of the sample on the reflection device in the rjght parallel bars with height and thickness correlated position to obtain sufficient intensity. to the reflective power. This latter format facili-

Notes and New Techniques GEMS & GEMOLOGY Winter 1989 227 Specular Sample Reflectance Area Aperture

Figure 2. This optical scheme shows how the sample interacts with the source of infrared light and the photometer through a series of mirrors (MI-M5) in the reflection accessory to produce the reflectance spectrum.

tates presentation of the data and con~parisonfrom This technique is particularly useful for the one gem material to another. The ability to present separation of some synthetics from their natural the results for many stones on a single piece of counterparts. This is the case for alexandrite paper (figure 4)allows for a very rapid and effective (figure 5) and for spinel (again, see figure 4). The identification of, for example, corundum from different sites occupied by the atoms in natural as spinel, calcite from aragonite, cubic zirconia compared to synthetic stones can be observed as a (djevalite) from strontium titanate (fabulite), and difference in the lattice vibration spectra. grossular garnet from pyrope garnet. Only type IIa As part of our study, we also investigated the diamond, which is transparent to the infrared effects of polarization. That is, on crystals that beam in the 100-1500 cm-1 range, cannot be have one or two optic , the incident beam is determined, although all of its common simulants partially polarized and the spectrum observed can be readily characterized by this method. depends on the orientation of the facet used and its

Figure 3. The reflectance spectrum of a pyrope garnet as it normally ap- pears (upper part) and as converted (lower pent) for this study. For the conversion, the recorded infrared spectrum (broken line) is expanded between 0 and 100% (continuous line). In this expanded spectrum, a

point represents each 10 cm - 1- The height of the bar at each point repre- sents variations in reflection inten- sity. That is, the bar is counted as nine units if the reflection intensity varies between 90% and 100%, as eight units if between 80% and 89%, and so on. The black regions show where the largest reflective power is located; to achieve this, one correlates the thickness of the bar to its height,

228 Notes and New Techniques GEMS & GEMOLOGY Winter 1989 ...... ;.. l~~i~n~n~L,l~M^kk~ll.i.i~~l~~illiiiJi~~l.Mi~~~l~~inm~ftawi~l~Mllllllll...... ,..,,,,., LUORITE : ...... ,:...... ,,.: ...... :a,~,llll!J-li ......

......

Figure 4. The authors recorded the reflectance spectra of at least five samples each of more than 60 gems, synthetic gems, and simzilants, and then converted their results to these simple bar graphs for easy comparison. The authors found no significant variability within a species for the materials they tested.

Notes and New Techniques GEMS &. GEMOLOGY Winter 1989 229 Figure 5. Natural and synthetic alex- andrite (here manufactured by Cre- ated Crystals) are easily separated by the reflectance method. Note, however, that because the bargraphs are simplified representations, the difference between the two spectra - that is, an additional weak reflec- tion observed between 1050 and SYNTHETIC 1100 cm-1 in the man-made stone-is better seen with the con- ventional spectra.

Figure 6. Although the position in which the sample is run does have some effect on the reflectance infra- red spectrum, all of the spectra are within the range for that gem mate- rial, thus allowing its identification. In the left-hand column, rotations (at 30Â steps) about the axis normal to the table of this faceted beryl in- duce these spectra, all of which are characteristic of this gem species. In the right-hand column, rotations (again, at 30Â steps) about the axis normal to the M (minor rhom- bohedron) and R (major rhom- bohedron) faces of a natural quartz -how only small differences from me spectrum to another. For a Z cut- the observed plate was cut per- pendicular to the Z (or optic axis) of the crystal; the same spectrum is obtained for any rotation about this axis (isotropic direction).

230 Notes and New Techniques GEMS & GEMOLOGY Winter 1989 position on the reflectance accessory. We found Leung C.S., Mkrigoux H.,Poirot J.l?, Zecchini P. (19861 Use of that while the spectra do differ slightly according infrared spectrometry in gemology. In Morphology and Phase Equilibria of Minerals, 1982 meeting of the Interna- to the position of the sample, overall they are still tional Mineralogical Association, Varna, Romania, pp. within the spectral range of that particular species 41 1-448. (figure 61. Ramirez O.A., Zecchini I?, Mkrigoux H. (1983) La espec- troscopia de reflexion I.R. en el estudio de cristales. Congreso Colombian0 de Qui'mica, Bucaramanga. CONCLUSION Ramirez O.A., Zecchini P., Mkrigoux H. (1985) La espe- External reflection infrared spectroscopy provides ctroscopia de reflexion I.R. en el estudio de cristales. Revista de la Universidad Industrial de Santander, Vol. a nondestructive method for identifying the min- 15, No. 1, pp. 5-23. eral species of most gem materials, whether loose Simon I. (1951) Spectroscopy in infrared by reflection and its or mounted in jewelry. Our results were obtained use for highly absorbing substances. Journal of the Optical Society of America, Vol. 41, pp. 336-345. with faceted stones, but they may also be obtained Simon I. (1953) Study of the structure of quartz, cristobalite, with uncut crystals that have at least one polished and vitreous silica by reflection in infrared. Journal of face. In some cases, such as (including Chemistry and Physics, Vol. 21, pp. 23-30. Zecchini l? (1986)L'utilizzazione della spectroscopia infrarossa alexandrite) and spinel, this technique can be used in gemmologia. Paper presented at the Decimo Convegno to determine the natural or synthetic origin of the Nazionale di Gemmologia, Valenza, Italy. stone as well. Zecchini P., Merigoux H.,Martin F. (1986) Nondestructive identification of gems and man-made stones by infrared spectrometry. Paper presented at the 14th General Meet- ing of the International Mineralogical Association, Stan- REFERENCES ford, CA. Zecchini P., Martin F., Mkrigoux H. (1987) Infrared spectros- Laroussi A. (1984) Calciil des Constantes Optiq~iesen Infia- copy for identification of gems and man-made stones.

rouse.2 cles Cristaux Utilises en Gen~moloeie.- Doctoral Paper presented at the 25th Colloquium Spectroscopicum thesis, Universitk de Franche-Comtk, France. Internationale, Toronto, Canada.

Notes and New Techniques GEMS & GEMOLOGY Winter 1989 23 1 MILDLY RADIOACTIVE RHINESTONES AND SYNTHETIC SPINEL-AND-GLASS TRIPLETS By Kurt Nassau and Edward A. Lewmd

Low levels of radioactivity were found in some green- let that consisted of a crown of rock crystal with a ish yellow to yellow-green (peridol-like) synthetic glass base containing uranium; he also noted the spinel-and-glass triplets, mirror-backed glass rhine- strong yellow-green fluorescence and "discrete stone chatons, and fully fashioned glass rhinestones. (banded or fluted)" fluorescence spectrum that is Uranium was detected in the radioactive stones. Al- characteristic of uranium. Unfortunately, the though individual stones in jewelry carry virtually piece was not tested for radioactivity, as this was no risk, it is recommended that parcels of such stones not be carried on one's person for prolonged not considered a significant issue at that time. periods. To confirm the source and determine the levels of radioactivity in these three types of gem sim- ulants, we examined several samples of each for both key gemological and chemical properties and for radiation activity (figures 1 and 2). Knowing that a broad variety of gemstones are candidates for irradiation treatment, many gem MATERIALS AND METHODS dealers routinely check all stones with a Geiger We obtained a wide variety of synthetic spinel-and- counter for radioactivity. This can often lead to glass triplets and glass rhinestones from several surprising results, as was the case a few months Manhattan stone dealers, from a mail-order find- ago, when a parcel of stones that should not have ing catalog, and from the authors' collections. We registered on the Geiger counter did just that. The ultimately focused on greenish yellow and yellow- dealer brought the stones to the authors' attention green peridot-like material since our initial survey and, as a result, we have located three types of of dozens of stones of all available colors showed commercially available gem materials that show radioactivity only in these two hues. Some of the low, but not negligible, radioactivity. mirror-backed rhinestones tested also had an iri- Comprising the first type are triplets that con- descent interference coating on the crown. sist of two layers of colorless synthetic spinel fused All 17 of the radioactive, as well as a selection of together with a thin layer of colored glass. Webster some of the nonradioactive, samples tested are and Anderson (1983, p. 463) refer to these as soudk described in table 1. Included as well are two pieces sur spinelles. According to trade sources, such of rough: SC2, a slab of triplet material of dimen- spinel triplets are currently manufactured in Eu- sions suitable for faceting small stonesj and NAc, rope in a wide range of colors for use in birthstone one of several pieces of unfaceted uranium glass jewelry, class rings, and the like. Only greenish obtained a few years ago at the Tucson Gem and yellow to yellow-green peridot-like material Mineral Show. showed radioactivity, although not all material of Conventional gemological testing was used to this color did. Comprising the second type are peridot-colored rhinestones that consist of a crown with a flat, silvered (mirror) back. Known as chatons, these also are currently made in Europe ABOUT THE AUTHORS and are usually sewn or glued onto clothing. Third, Dr. Nassau, recently retired from AT&T Bell Laboratories, is now a visiting professor at Princeton University as well as a tree- we found radioactivity in some fully faceted glass lance writer and consultant in Lebanon, New Jersey. Mr. rhinestones, again of the same yellow-green color. Lewand is a graduate gemologist and appraiser tor Marcus & The use of lead oxide in glass to give it high Co., New York City. dispersion, so-called flint glass, is well known Acknowledgments: The authors wish to thank G. M. Sturchio and P. L, Trevor, of AT&T Bell Laboratories, for the gamma-ray (Webster, 1983, p. 437), as is the use of uranium spectroscopy and X-ray fluorescence measurements, respec- compounds to produce a yellow-to-green color tively. (Nassau, 1983; Webster 1983, p. 441). In fact, Gems & Gemology, Vol. 25, No. 4, pp. 232-235 Webster (1952)reported examining a yellow doub- 0 1990 Gemological Institute of America

232 Notes and New Techniques GEMS & GEMOLOGY Winter 1989 Figure 1. Some of the radio- active stones tested include, from left to right: back - LE, (a rhinestone), GR, and 1 LEy (synthetic spinel-glass triplets); front- GO, and GR2 (synthetic spinel-glass triplets), SWy (a chaton). Phoio by Robert Weldon.

determine the optical constants and fluorescence for all of the radioactive samples and some of the nonradioactive specimens as well. The color de- scriptions are also given in ISSC-NBS Centroid color numbers (Kelly and Judd, 1976). Qualitative chemical analysis for five representative speci- mens (in the case of the triplets, for the glass exposed at the girdle) was performed on an X-ray fluorescence unit using a chrome target and a solid-state energy-dispersive detector with a PGT System 4 analyzer. Note that under these condi- tions one cannot detect chromium, vanadium, or elements llelow aluminum in the periodic table. A Solar Electronics Radiation Alert Monitor 4 Geiger counter (thin-window type) was used to screen the stones for radioactivity. With a stone placed against the probe area, we averaged several one-minute counts for each specimen; the small- Figure 2. Some of the nonradioactive stones est stones were measured three at a time. The tested include, from left to right: back - GO3 results are given in table 1 as radiation levels in and LE, (synthetic spinel-glass triplets), LEi (a terms of multiples of background, which is 12 rhinestone); front-SW, and NA, (chatons), counts per minute for this instrument in the test NAa (a rhinestone). Photo by Robert Weldon. location used. We considered any reading lower than 1.5 times background to indicate absence of spinel, are consistent with those reported by Kane radioactivity by this test. More detailed radioac- (1986)for synthetic spinel-and-glass triplets. The tivity and elemental measurements were per- glass layers ranged from 0.3 to 0.5 mm thick, formed on three of the stones with a gamma-ray contained gas bubbles, and were reasonably well spectrometer, using a lithium-drifted germanium centered at the girdle. The rhinestones in table 1 detector with a Canberra Series 80 multi-channel showed an R.I. of 1.57 to 1.58, with strain visible in analyzer and two-hour counting periods. the polariscope, gas bubbles and flow lines, and conchoidal fractures; all of these results are con- RESULTS AND DISCUSSION sistent with lead-containing glass. Gemological Data. All of the triplets in table 1 All of the radioactive triplets showed medium to showed a refractive index of 1.729 to 1.730, which strong greenish yellow fluorescence to short-wave is consistent with synthetic spinel; some stones radiation and were inert to long wave. The non- also showed a weaker indication of 1.69, derived radioactive glass chaton SW, had a similar fluores- from the glass. These results, as well as the cence reaction, but radioactive SW2 fluoresced a anomalous double refraction typical of synthetic greenish yellow that was very weak to short-wave

Notes and New Techniques GEMS & GEMOLOGY Winter 1989 233 - - - - ~ - TABLE 1. Glasses and synthetic spinel-and-glass triplets surveyed for radioactivity.

Sample Color Size Weight Radio- no. Colora no.'= (mm) Shape (ct) activity"

Synthetic Spinel-and-Glass Triplets LEI Yellow-green Oval GO3 "Emerald" green Oval R~I Yellow-green Oval GR3 Yellow-green Emerald LE2 Greenish yellow Pear GR1 Greenish yellow Oval GRo Yellow-green Oval GO1 Yellow-green Oval Go2 Greenish yellow Oval GO4 Greenish yellow Oval GOgd Yellow-green Round SCld Yellow-green Pear SC2 Yellow-green Slab Glass, Faceted and Rough LE3 Yellow-green Pear NAi Colorless B Chalon NA3 Green BC Round NA4 Blue BC Round sw, Greenish yellow B Chaton SW, Yellow-green B Chaton LE4 Greenish yellow Oval LEs Greenish yellow Oval NAc Greenish yellow Rough

aB indicates a mirror back; C, an iridescent surface coating, ¡Colo number from the ISSC-NBS Centroid Color Chart (Kelly and Judd, 1976). 'Activity as number of times background; - indicates less than 1.5 times background; background was 12 counts per minute: the activity of 13 for NAc corresponds to a reading of 0.14 mRIhr. ^Consists of three stones; weight and radioactivity level are the totals for all three.

U.V but strong to long wave. Moreover, the triplet TABLE 2. Elemental analyses (as determined by fluorescence observed here differs from that re- X-ray fluorescence) of the glass in some of the stones ported on similar material by Kane (1986).Accor- in table 1. dingly fluorescence cannot be considered diagnos- tic for radioactivity. Elements detectedh Sample Radio- High to Elemental Composition. X-ray fluorescence con- no. Color and type activitya medium Low firmed that the synthetic did not contain LEo Greenish yellow triplet 1.5 Pb, Si, K, Zn U, Cu any significant amounts of metallic elements SWp Yellow-green glass other than the expected Mg and A1 (again,note that chaton 4 Pb, K, Zn U, Cu Cr, and elements lighter than A1 could not be LEI Yellow-green triplet - Pb, Si, Ca, K Fe, Cu LE3 Yellow-green glass detected). Partial analyses of the glass for represen- rhinestone - Pb, Si, K, Bi Cu tative yellow-green and greenish yellow samples, SW, Greenish yellow glass both with and without radioactivity, are shown in chaton - Pb, Si, K, Ti - table 2. All of the radioactive samples tested by aT~mesbackground, as in table 1. elemental analyses or gamma-ray spectroscopy bElements not detectable under the analysis conditions used, but that were found to contain uranium, which was clearly could be present, include B, LI, Na, Cr, and K the coloring agent.

Radioactivity. Table 1 shows a range of radioac- observed on the two sides of the triplet slab, since tivity up to five times background in the faceted there is less absorption of the gamma rays from the material and up to 13 times background in a piece uranium in the glass on the thinner synthetic of rough uranium glass. Different counts were spinel side intended to be the crown of the triplet.

234 Notes and New Techniques GEMS & GEMOLOGY Winter 1989 Gamma-ray spectroscopy of three samples TABLE 3. Gamma-ray spectroscopy of three showed that the observed radioactivity was de- radioactive stones from table 1. rived from natural (nondepleted) uranium and its daughter products. The measured radioactivity in Radio- Sample Radio- activityb nanocuries per gram (nCi/gm) is given in table 3. no. Color and type activity8 (nCi/gm) Although acceptable limits for radioactivity estab- lished in the U.S.A. vary considerably depending GRl Greenish yellow spinel triplet 1.5 0.44 on a number of factors, 0.4 nCi/gm (NRC) and 2 GR, Yellow-green spinel triplet 1.5 0.38 nCiIgm (DOT)have been reported for certain gem SW, Yellow-green glass chaton 4 4.0 applications by Ashbaugh (1988). Some of the "Times background, as in table I. stones are clearly above the lower of these accept- bAs determined by gamma-ray spectroscopy; error 220%. ability limits.

CONCLUSIONS Three types of greenish yellow to yellow-green U.S. government limits, they probably present no (peridot-like) materials have been found to be hazard under normal wearing conditions. The radioactive: some synthetic spinel-glass triplets dealer who carries a large parcel of such materials (in which the glass layer contains uranium as the in a pocket for a prolonged period of time may, colorant), some uranium-glass rhinestones in the however, be at some risk. Since similar colors can form of silver-backed chatons, and some fully be produced in glass without the use of uranium, it fashioned uranium-glass rhinestones. Although is difficult to understand why uranium-containing the radioactivity in some of these stones exceeds glass is still being used in jewelry today.

McClellan G.W,, Shand E.B. (1984) Glass Engineering Hand- Ashbaugh C.E. (1988)Gemstone irradiation and radioactivity. book, 3rd ed. McGraw Hill Book Co., New York. Gems e9 Gemology, Vol. 24, No. 4, pp. 196-213. Nassau K. (1984) The Physics and Chemistry of Color. John Kane R.E. (1986)Imitation emerald: Synthetic spinel-and-glass Wiley & Sons, New York. triplets. Gems a) Gemology, Vol. 22, No. 4, pp. 236-238. Webster R. (19521 Some unusual con~positestones. Gems &> Kelly K.L., Judd D.B. (1976)Color. National Bureau of Standards, Gemology, Vol. 7, No. 6, pp. 186-187. Special Publication 440 (including Standard Sample No. Webster R. (19831 Gems: Their Sources, Descriptions and 2106, 19651, U.S. Government Printing Office, Washing- Identification, 4th eel. Revised by B. W. Anderson, Butter- ton, DC. worths, London.

Notes and New Techniques GEMS & GEMOLOGY Winter 1989 235 EDITOR C. W. Fryer Gem Trade Laboratory, West Coast CONTRIBUTING EDITORS Robert Crowningshield LAB NOTES Gem Trade Laboratory, East Coast Karin N. Hurwit Gem Trade Laboratory, West Coast Robert E. Kane Gem Trade Laboratory, West Coast David Hargett Gem Trade Laboratory, East Coast

AMBER, Plastic Imitation 0.55 mm at its longest point, appears to be a reddish orange almandine- A large translucent-to-opaque or- pyrope garnet, similar to published ange, white, yellow, and brown piece descriptions (see, e.g., Photontlas of of rough- was submitted to the West Inclusions in Gemstones, by E. J. Coast laboratory for identification. Gubelin and J. I. Koivula) of conlpara- The piece measured approximately 28.7 x 20.5 x 28.0 cm. Our client reported that it had been represented Figure 2. When the host dia- as amber when he purchased it in mond is viewed face up, this Tahiti; he was told that it had been included crystal appears to be found floating offshore there. half black and half orange. The appearance of the piece was Figure 1. This 28.7 x 20.5 x Note also the dodecahedra1 rather unusual. One side had a thin 28.0 cm plastic imitation am- face. Magnified 35 x . white coating over a brown area ber shows numerous gas bub- where a few brolzen sections revealed bles and unnatural stamped a third layer that was orangy brown. depressions. The other side (figure 1)had some of the white coating plus what appeared to be stamped in~pressions.In addi- tion to numerous gas bubbles, this spectral curve closely matched a side also had a broken portion that standard curve for polyvinyl chlo- revealed a dark yellow interior. ride. RK In general, the piece resembled slag material from a plastics factory. Be- cause of its size and the rough- sur- DIAMOND face, we could not get either a spe- With an Almandine-Pyrope cific gravity (although the "heft" test Figure 3. When the diamond in Garnet Inclusion indicated it was very low) or a refrac- figure 2 is lipped slightly, the tive index. However, a thermal reac- While grading a 1.25-ct diamond re- true orange color of the entire tion tester the slightly cently in the West Coast laboratory, included crystal becomes visi- we noticed the unusual appearance acrid odor that is typical of many ble. Magnified 27 x , plastics. An infrared spectral anal- of a transparent crystal inclusion. As ysis performed by the GIA Research evident in figure 2, when the dia- Department confirmed that the ma- mond is viewed face-up, the crystal terial was indeed plastic. The IR appears to be half black and half orange. Because of the high refractive index of diamond, the color of inclu- Editor's Note: The initials at the end of each ded crystals may sometimes be item identity the contributing editor who masked, either partially or entirely. provided that item. In this case, when the diamond is Gems & Gemology, Val. 25, No. 4, pp. 236- tilted, one can see that the entire 243. crystal is actually orange (figure 3). 0 1990 Gemological Institute of America This inclusion, approxin~ately

236 Gem Trade Lab Notes GEMS & GEMOLOGY Winter 1989 Figure 4. The light yellow Lips and neur-color- Figure 5. When exposed to long-wave U.V, rudi- less center give this 0.69-ct marquise-shaped di- ation, the light yellow tips fluoresce a very amond the distinctive appearance of a true strong chalky yellow, while the near-colorless bi color. center fluoresces a very strong blue ble stones, which would place the quise-shape brilliant-cut diamond strong, sharp 415-nm line, but the origin of this diamond in the eclogi- that was truly a bicolor (figure 4).The rest of the "Cape series" lines at 423, tic suite of kinlberlites. Of course, center portion was near colorless (ap- 435,452,465, and 478 nm were very since the inclusion does not break the proximately an H on the CIA color- weak. The light yellow tips of the surface of the diamond, it is imposs- grading scale], and both tips were marquise cut did not show any ab- ible to prqve the con~positioncon- light yellow (in approximately the T sorption lines or bands. When the clusively without damaging the host. to U range on the same scale). diamond was placed over the strong ~~~icall~,diamond imposes its When the diamond was exposed to light source from the opening of the own crystal structure on inclusions. long-wave U.V. radiation, we ob- iris diaphragm on the spectroscope Consequently, the faces visible on an served a distinctly zoned fluores- unit, the near-colorless center por- included crystal are actually nega- cence: the center portion a very tion showed a strong blue transmis- tive diamond faces, not those charac- strong blue, with both tips a very sion luminescence. However, the teristic of the included mineral. (The strong chalky yellow (figure 5). The light yellow areas did not show any term xenohedral is used to describe a zoned fluorescence appeared to cor- transmission luminescence. crystal inclusion bounded by faces of respond directly to the near-colorless When the diamond was examined its host mineral.] In this case, how- and light yellow portions seen in under the microscope with diffused ever, we cannot tell if the dodeca- visible light. When the long-wave lighting, both in air and while im- hedral face visible in figure 2 belongs lamp was turned off, the entire dia- mersed in methylene iodide, no line to the garnet or is imposed by the mond exhibited a very weak chalky of demarcation was observed be- diamond's structure, because both yellow phosphorescence that lasted tween the light yellow and near- belong to the cubic system. approximately 10 seconds. Inter- colorless areas. The study of included crystals in estingly, the phosphorescence did not Although we occasionally see dia- diamond enables scientists to deter- appear to be zoned. The fluorescence monds that are strongly and irregu- mine what elements are present deep to short-wave U.V. radiation was es- larly zoned yellow and near colorless, within the earth where the diamonds sentially the same as to long-wave, this is the first one that possessed a crystallized. If there are no breaks except that the intensity was moder- symmetrical bicolor appearance to between the surface of the diamond ate rather than very strong. Although the unaided eye. R IZ and the inclusion, then scientists the diamond did phosphoresce after know that the inclusion has re- exposure to short-wave U.V. radia- mained compositionally unchanged tion, the phosphorescence was ex- With a Color-Change since its creation more than 150 kin tremely weak and very short lived. Garnet Inclusion deep in the earth's crust. The absorption spectrum of this The West Coast laboratory recently Holly Baxter stone was examined at room tem- received a 0.58-ct diamond for qual- perature using a spectroscope unit ity analysis. This diamond was found Bicolored equipped with a Beck "hand-held" to contain a very unusual inclusion, The West Coast laboratory recently type of prism spectroscope. The a color-change garnet, which was studied a most unusual 0.69-ct mar- near-colorless portion exhibited a red-purple in incandescent light (fig-

Gem Trade Lab Notes GEMS & GEMOLOGY Winter 1989 237 ure 6, left) and saturated green in fluorescent light (figure 6, right). The included crystal, approx- imately 0.25 x 0.30 mm, was par- tially exposed on the surface of the pavilion. Using X-ray fluorescence analysis, Dr. Emmanuel Fritsch of the GIA Research Department deter- mined that , aluminum, and silicon were present, with a trace of iron and chronlium, but found no indication of any manganese. This Figure 6. This inclusion in diamond appears red-purple in incandes- suggests that the crystal is a color- cent light (left) and green in fluorescent light (right).Magnified 25 x change pyrope garnet. The diamond contained other nm. Because the stone was dark and two millirenls per hour was from the wholly included crystals; one near the heavy gold setting covered an setting, we wrapped the green dia- the table showed a very faint change unusually large portion of it, we mond with lead foil and again of color. One should always examine could not see the tell-tale green checked the entire ring with the colored inclusions in dian~ondwith 'mossy" patches that result from radiation detector. The significant both incandescent and fluorescent radium treatment until we illumi- reduction in detectable radiation light to see if there is a color change. nated the diamond with a FiberLite. proved that the source of the original Soheila Jalali We then noted a few very subtle reading was the green diamond. Radium Treated green stains on the pavilion (see p. Although this stone did not have as 164 of the Fall 1987 issue of Gems d high a level of residual radiation as The East Coast laboratory recently Gemology for a photo of such stains). has been reported in other radium- encountered a green pear-shaped dia- Mr. John Haynes, who has treated treated diamonds, we would not ad- mond (approximately 9.70 x 8.00 x diamonds with another type of radio- using it in jewelry. 3.70 mm) that was bezel set as an active salt, americium, reports that Tom Moses accent stone to a 6-ct fancy light green diamonds treated by his yellow round diamond (figure 7). method do not show these nlossy When examining green dianlonds to Treated Crystal patches (pers. comin., 1989). determine origin of color, we rou- In recent months, the laboratories on To rule out the possibility that the tinely use a Geiger counter to test for both coasts have received a greater- reading from the Geiger counter of radioactivity. This stone turned out than-normal number of fancy color to be radioactive, probably as a result diamonds for examination. With this of having been treated with radium Figure 7. The green pear- trend, we have also encountered salts earlier in this century. shaped diamond seen here as a more treated diamonds. Particularly Although encountered infre- side stone to the 6-ct fancy rare is an irradiated rough diamond quently today, artificial coloration of yellow diamond at the bottom crystal submitted for examination to genlstones by treatment with ra- was found to be radioactive. the East Coast laboratory. Although dium was first reported in 1909. In we have seen two such crystals in the 1916, Sir William Croolzes, repor- past, this is the first we have had an tedly the first to experiment with opportunity to photograph and laboratory irradiation of diamonds, report. presented a small blue-green octa- This 2.95-ct well-formed bluish hedron to the British Museum that green octahedron was low in clarity he had treated with radium salts in and lacked the natural green irradia- 1914 (see Gems d Gemology, Sum- tion stains usually seen on the sur- mer 1950, p. 3 17). face of natural-color green diamond The pear-shaped diamond we ex- crystals. More significantly, as is evi- amined was medium dark green in dent in figure 8, the coloration was color and showed no luminescence very superficial and was concen- when exposed to either long- or trated along the crystal edges. This short-wave U.V radiation. Although was most likely the result of electron the setting restricted our observa- or alpha-particle treatment. tions with the hand spectroscope, we The diamond did not luminesce to did see a pair of lines at 498 and 504 either long- or short-wave ultraviolet

238 Gem Trade Lab Notes GEMS & GEMOLOGY Winter 1989 radiation. The absorption spectrum, observed with a CIA spectroscope unit, showed a line at 415.5 nnl, a pair of lines at 498-504 nm, and a weak, but sharp, line at 594 nm, a spectrum that is commonly observed in treated diamonds. Tom Moses

Figure 8. A magnified view (10 x ) of this treated diamond crystal shows that the color has very shallow penetration ¥ is concentrated along the w.q of the crystal.

Figure 9. Although all four of these 9-mi , ~cleitebeads were im- pregnated with plastic, the treatment was more successful on the inner pair than on the outer two.

within and around the holes of with the iron-stained cracks masked both types of beads showed a foreign to improve the overall color appear- colorless material. When touched ance of the material. lightly with the hot needle of the Using a Nicolet 60SX-FTIR spec- thermal reaction tester, the very soft trometer, Dr. Emmanuel Fritsch was material started to flow and give off able to record the infrared spectrum an acrid odor. This indicated that of the treated beads [figure 10).The both types of beads had actually been peaks in the area of approximately impregnated with a plastic. We con- 6200 to 5500 wavenumbers are those Impregnated JADEITE cluded that the lighter colored beads of jadeite jade; all others can be had been treated more successfully, attributed to a plastic, Bob Rosen- Our West Coast laboratory learned that a new type of treatment was being used in the Orient to improve Figure 10. Only the peaks in the 6200-5500 wavenumber range of the appearance of some jadeite jade. this infrared absorption spectrum of one of the beads in figure 9 Four sample beads, each measuring can be attributed to jadeite; all of the others represent a plastic. approximately 9 mm in diameter, were loaned to us for examination. As can be seen in figure 9, the center pair of beads looks quite different from the outer two. We were told that the center two slightly yellowish green beads are representative of the material after treatment, whereas the outer two darker brownish green beads represent the untreated mate- rial. With magnification we noticed that the "treated" material appeared to be more homogeneous in struc- ture; few of the tiny cracks that are usually present in jadeite jade were visible. The "untreated" beads showed numerous cracks that seemed to be filled with iron stains, thus giving the beads their brownish appearance. However, the area

Gem Trade Lab Notes GEMS & GEMOLOGY Winter 1989 239 thal, of Nicolet Instrument Corpo- union suggests that they were ration, reported that the plastic is worked from blister pearls. If it went probably a mixture of different poly- undetected, such an acrylates, although a definite conclu- would appear to be an important sion is not possible without destruc- pearl because of its large size. Our tive testing. KH report concluded: 'Assembled pearl consisting of two sections of natural pearl or blister pearls cemented to- ^ gether." Tom Moses Assembled PEARL In most cases, identification of Figure 13. When a companion mounted pearls does not present a CULTURED PEARL, to the 9-mn~treated black cul- problem. The X-radiograph in figure Treated Black tured pearl at the left was 11, taken at the East Coast labora- sawed in half, it revealed a rim tory, shows a large [approximately The West Coast laboratory had the of ^ck , thai 18.75 x 17.30 mm) half-drilled rare opportunity to see the interior of fie pearl had been dyed. slightly pear-shaped pearl a cultured pearl that had been treated that was set in a yellow metal ring. to give it a black color. A jeweler from Although this X-radiograph seemed Texas discovered that a triple strand exposed to long-wave U.V radiation, to indicate natural origin, it was not of cultured black pearls, which had neither of the pearls showed the conclusive. After several more X-ra- been represented to him as being of brownish red fluorescence that is diographs were taken, all with unsat- natural color, were actually arti- characteristic of natural-color Tahi- isfactory results, we asked the client ficially enhanced. He sent us a few tian black cultured pearls; instead, to remove the pearl so that we could loose brownish black pearls from the both remained inert, proving that examine it unmounted. together with one that he they had been artificially enhanced. We were surprised to find that the had cut in half for research purposes. The CIA Research Department unmounted pearl actually was as- Figure 13 shows one of the loose has been studying the chemistry of sembled (figure 12), a fact that had pearls, which measured approx- the nacreous layers in black pearls by been carefully concealed in the gal- imately 9 mrn in diameter, next to means of X-ray fluorescence. XRF lery work of the setting. Neither sec- half of the cut pearl. The striated analysis of these two pearls hwed tion fluoresced to X-rays, and a sub- grayish bead nucleus and a brownish the Presence of a high amount of sequent X-radiograph proved that black nacreous layer approximately silver in both, indicating that they both sections were of saltwater natu- 2-mnl thick are readily visible. When had bee11 dyed, probably with a silver ral origin. The fact that both pearls nitrate solution. Con~parativean- had slightly flared outlines near the alyses have shown that natural-color black pearls do not show any traces Figure 12. When the pearl of silver. KH shown in figure 11 was un- Figure 1 1. This X-radiograph of mounted, it became readily A large (18.75 x 17.30 mm) apparent that it had been as- mounted pearl suggests, but sembled, possibly from two Damaged "Burma" RUBY does not conclusively prove, blister pearls. natural origin. Recently the East Coast laboratory had the pleasure of identifying an attractive untreated ruby that was mounted in an older yellow and white metal lady's ring set with old- mine-cut brilliants, single cuts, and Swiss cuts. The stone displayed the patches of short rutile needles and irregular "treacle" color zoning that are characteristic of Burma . In addition, it luminesced strongly to both long- and short-wave U.V radia- tion. The stone appeared to be in exceptionally fine condition. Several weeks later the stone and ring, which we recognized imme-

240 Gem nade Lab Notes GEMS & GEMOLOGY Winter 1989 diately, were returned to us for a damage report. The ruby was now so badly fractured (figure 14) that it could not be repaired. We examined the fractures in question using an overhead light source and a high-magnification con- trast-interference microscope. The fractures lacked undercutting and polishing drag lines where they reached the surface, thus proving that they had occurred after the stone was last polished and, therefore, were not inherent. The nature and extent of the fractures indicated that the 1 damage was probably the result of a rapid temperature change. While examining the mounting, we noticed new metal at the end of a pitted prong next to one of the dia- monds, a sign that it had been re- tipped. This was probably the cause of the damage. why the ruby was Figure 16. This magnificent 15.18-ct dark violetish blue subjected to the heat of retipping the is from the newly discovered Sao Jose da Batulha mine, in IJaraibu, prongs and not removed from the setting first &-the real mystery. 8 , I DH 26.1 1-ct stone was reportedly from was reported by our West Coast labo- Burma. The largest cut scapolite, ratory in the Summer 1985 Gems s) also from this locality, is believed to Gemology. Nicholas DelRe be the 288-ct colorless stone reported -- in the January 1978 issue of the Journal of Gemmology However, fine-color purple scapolites in sizes Blue TOURMALINE over a few carats are not common. from Brazil Scapolite in a fibrous rn m and translucent form In recent months, laboratories on that may dis- bth coasts have a number of Figure 14. The numerous frac- play chatoyancy cut en cab- tourmalines from the new locality in tures in this natural ruby 1(8,60 ochon. A 52.92-ct - Brazil, ~h~ East coast labo- x 6.20 x 3.80) probably re- ratory examined two tourmalines Figure 15. This 26.11 -ct purple suited when the stone was from this locality of a fine "" scapolite is ~in~;suullylarge for heated during a retipping of blue color, known in the trade as such a color. the prongs. Magnified 10 x . "indicolite," the larger one weighing 5.71 ct. The samples tested had the normal gemological properties for tourmaline. DH Large Purple SCAPOLITE The West Coast laboratory re- Although scapolite occurs most fre- ceived for identification an extraor- quently in colorless to yellow trans- dinary 15.18-ct oval modified bril- parent crystals, it is also found in liant cut, dark violetish blue tour- other colors; purple is one of the most maline (figure 16) that was reported popular. An unusually large (17.61 x to be from this same locality. When 16.36 x 15.20 mm] transparent pur- viewed table up with standard "day- ple oval mixed-cut scapolite recently light equivalent" illumination, the came to the attention of the East stone somewhat resembles a fine tan- Coast laboratory (figure 151. This zanite. This color is unlike any previ-

Gem Trade Lab Notes GEMS &. GEMOLOGY Winter 1989 241 ously reported for blue tourmalines from approximately 400 to 428 nm. (particularly in this size range]. The spectrum observed perpen- As mentioned in the Gem News dicular to the c-axis was verv similar. section of the Fall 1989 issue of except for the absence of the line Gems el Gemology, faceted stones slightly above 539 nm and the fact from this new Paraiba find (more that the lines at 453 and 461 nm were precisely known as S3o Jose da weaker. As reported in the Gem Batalha) are usually less than 1 ct. To News section of this issue, prelimi- the best of our knowledge, this is the nary work by the GIA Research De- largest fine faceted violetish blue partment indicates that the color of tourmaline reported from that lo- this stone is probably caused by the cality to date. presence of Mn3+ together with Identification of the stone as tour- Cu2+. European researchers have maline was confirmed by standard reached a similar conclusion based gemological testing. It was deter- on like-color material from this lo- mined to be uniaxial negative and to cality (E. Gubelin, pers. conlm., have refractive indices of 1.620 and 19891. Figure 17. These 5-mm "zir- 1.640, with a corresponding birefrin- To insure observation of even the coma" were found to gence of 0.020; a specific gravity of weakest fluorescence, we exposed be foil-backed glass. 3.07 was determined by the hydro- the stone to both long- and short- static method; very strong pleochro- wave U.V radiation in a darkened ism was obvious to the unaided eye. room, placing it within a few inches tions, for example, are familiar to With a calcite dichroscope, we ob- of the ultraviolet lamp. The tour- jewelers and consumers alike. At the served strongly dichroic colors of maline showed no visible fluores- East Coast laboratory, however, we dark blue-violet parallel to the c-axis cence to either source. were surprised to encounter glass and medium greenish blue perpen- We also checked the stone for color imitations of cubic zirconia, which dicular to the c-axis. zoning by immersing it in sesame oil in itself is a relatively inexpensive The visible-light absorption spec- (R.I. of 1.471, which was chosen be- material and certainly not a gem. trum was examined with a GIA Gem cause it is nontoxic. When the stone The earrings shown in figure 17 Instruments spectroscope unit with was viewed over diffused illuinina- were offered as an incentive to attend a Beck prism spectroscope at room tion, the overall blue coloration as a real estate sales presentation. These temperature. This unusually colored seen with the unaided eye was even. 5.00-mm round brilliants were la- tourmaline had a very interesting However, there was a very subtle beled zirconia. A trained observer absorption spectrum. Parallel to the zone, moderate in size, of faint purple would immediately notice the c-axis there were only two major arranged in a "Y"-shaped pattern ori- molded appearance and the lack of areas where light was transmitted: ented parallel to the c-axis that ap- the dispersion that is characteristic one in the violet, violet-blue, blue, peared to extend throughout most of of true CZ. The pavilions of both and part of the blue-green; and the the stone. The "Y"shape was remi- stones were coated with a reflective other in portions of the blue-green niscent of the growth features that substance (foil backed] to give them and green regions. Within the violet, run down the c-axis of some Bra- the appearance of having more bril- violet-blue, and blue transmission zilian "imperial" . liance than the low refractive index areas we observed a moderately Examination of the stone with a (1.57) would provide. DH strong diffuse band centered near 453 microscope and darkfield illumina- nm and a thinner diffuse band of tion revealed subtle, straight parallel moderate intensity at approximately growth features throughout most of FIGURE CREDITS 461 nm. We also noted, in the green the interior. In addition, a few small Figures I, 4, 5, and 16 are the work of region, a strong sharp line slightly needles and minute white crystals Shane McClure. Holly Baxter took figures above 539 nm, with a vague emission were observed in random orienta- 2 and 3. The two views in figure 6 were [bright) line at around 538 nm. In t ion. R IZ taken by Robert E. Kane. David Hargett addition to these areas, there was a provided the pictures in figures 8, 14, and 17. Nicholas DeIRe supplied figures broad strong absorption area block- 7, 12, and 15. Robert Weldon is responsi- ing out all of the red and most of the Imitation ble for figures 9 and 13. The infrared ab- orange (approximately 605 to 700 sorption spectrum chart shown in figure CUBIC ZIRCONIA nm] as well as a general, moderate to 10 was produced by Dr. Emmanuel Fritsch. The X-radiograph in figure 11 is weak, absorption from around 500 to By definition, an imitation is fash- the work of Tom Moses. John 1. Koivula 540 nin and a somewhat narrower ioned to closely resemble a more took the photomicrographs in the "Histori- strong dark absorption in the violet valuable gem. Many diamond imita- cal Note" section.

242 Gem Trade Lab Notes GEMS &. GEMOLOGY Winter 1989 A HISTORICAL NOTE Highlights from the Gem Trade Lab 25,15,and. five years ago

WINTER 1964 black from Hawaii and a calcareous inverted. Other items of interest type of a rare blue color that was from were a color-change spinel, natural The New York laboratory reported on an unknown source. pale color corundun~beads with red their examination of the famous dye that was visible in the drill holes, 43.48-ct Nassak diamond, which is and illustrations to help separate oo- of top color and flawless. Additional litic from sugar treated. To WINTER 1984 notes referred to Brazilian emeralds someone who is not familiar with the without chromiun~,pressed amber, A very small (0.02 ct) single-cut dia- appearance of these two opal types, odontolite, and some rare-earth syn- mond was seen to have a unique separation can be difficult. The com- thetic crystals. diamond crystal inclusion. Because parison photomicrographs are re- A pink pearl that was sawed in half it was loose in a cavity that was open peated here to help clarify the differ- to make a pair of earrings was seen in to the surface, the included crystal ence. the Los Angeles laboratory. Large actually protruded above the table of knots in diamond, "pigeon's eye" the host diamond when the host was nephrite, and needles in quartz that were identified by X-ray diffraction In sugar-treated opal, shown as tourmaline were also discussed. here at 45 X, the small black The American Gem Society's defini- Circular black spots Identify irregular concentrations of dye tion of flawless was mentioned and the natural structure of oolitic appear only in the interstices illustrated with photos. , , opal. Magnified 20 x . and cracks of the opal.

WINTER 1974 Synthetic opal, Slocum stone, and a number of other opal imitations were compared with natural in the report from the New York laboratory. The Los Angeles laboratory dis- cussed at length a new pulled syn- thetic alexandrite. Its transparency to short-wave ultraviolet light was compared with that of flux-grown synthetics and natural alexandrite. Photos showed that the pulled matc- rial was more transparent than its flux-grown counterpart, which in turn was more transparent than the natural stone. Different types of coral were mentioned, including

Gem Trade Lab Notes GEMS & GEMOLOGY Winter 1989 243 John I. Koivula and Robert C. Kammerling, Editors

DIAMONDS new recrush plant in Jwaneng; the $105 million plant is Filled diamond update. The Summer 1989 Gems d scheduled to begin operation in April 1990. Gemology article on filled diamonds stated that "there is Botswana's output, in terms of value, is second only to no practical way to remove all of the filling material" that of the Soviet Union; Debswana accounts for approx- from a treated stone. Following publication of the article, imately 55% of De Beers's total diamond output and Mr. Isaac Landerer, one of the principals of the New York about half of its profit. Despite these figures, dian~onds firm that performs diamond filling, Dialase, advised us are becoming increasingly difficult to recover from that the filling material could, in fact, be completely Botswana's three mines, and several companies-inclucl- removed. To support his claim he offered to supply a ing De Beers-are exploring for new deposits. None of treated stone that we could examine and document both the many deposits discovered to date is considered before and after the filling material was removed. commercially viable. (Diamond Intelligence Briefs, Vol. The stone subsequently provided was a 0.85-ct round 5, No. 88) brilliant. With magnification, a surface-reaching break in the stone exhibited a number of features characteris- Ghana may privatize mines. Sofren~ines,a French-based tic of filled diamonds, including both orange and blue firm, is preparing a study on the rehabilitation and "flash effects" and gas bubbles trapped in the filling possible privatization of the Birim dian~ondfield in material (figure 1, left). EDXRF chemical analysis re- southern Ghana. Production in Birim has dropped from vealed the presence of lead in the filling. The dian~ond 2.6 million carats in 1966 to 200,000 carats in 1988, as a was then returned to Mr. Landerer for removal of the result of unstable funding and outdated equipment. The filling substance, reportedly by a deep-boiling technique new study reportedly emphasizes acquiring mobile in an undisclosed medium. When he sent the stone back, equipment, which could be used in each sector for three magnification revealed no visual indications of treat- to four years. Total reserves in the Birim field are ment in the previously filled break (figure 1, right). estimated to be between 26 and 29 million carats. Furthermore, EDXRF analysis did not detect any lead (DiamondInternational, October 1989) where it had previously been noted. It thus appears that the so-called "Yehuda" filling treatment can be reversed, Diamond cutting expands in Mauritius. The tiny Indian although we do not know the specific conditions of the Ocean island of Mauritius, known for its stable social, removal process. political, and economic environment, is attracting grow- ing interest from diamond manufacturers. Located 2,500 Diamond exploration in Pilbara, Australia. Perilya lim from South Africa's coast, the island is home to three Mines and Canada-based Noranda, Inc., have arranged a operating dian~ondplants, and a fourth is under con- joint venture to invest US$570,000 for dian~ondexplora- struction. currently, the island's dian~ondindustry em- tion in the Pilbara area of Western Australia. The ploys 1,550 workers. exploration is in its infancy, but researchers believe the The existing firms in Mauritius-L.S.P. Ltd., Bels- earlier discovery of a 0.3-mm gem-quality diamond on diain, and Universal Diamonds-all have their roots in the Nullagine project could lead to a major diamond Antwerp. The new plant is owned by India-based Pattel source. [Diamond Intelligence Briefs, Vol. 5, No. 9 1-92) Ltd. In 1988, Mauritius accounted for just under US$7 million in rough diamond imports from Belgium, a Increased diamond output in Botswana. The Botswana 130% increase over 1987. (Diamond International, Oc- Diamond Valuing Company plans to raise its diamond tober 1989) output by 12%, to 17 million carats, in 1990. To achieve this goal, the company will add 60 new diamond sorters Diamond exploration on the west coast of South Africa. to its existing work force of 280 sorters in Gabarone. John Gurney, chairman of the South Africa-based explo- Additionally, Debswana, the mining company co-owned ration company Benguela Concessions, says there is by De Beers and Botswana, is funding construction of a evidence that approximately 20 million carats of poten- tially gem-quality dian~ondshave accumulated off the west coast of South Africa. The diamonds have eroded from river deposits and been carried into the shallow Gems & Gemology, Vol. 25, No. 3, pp. 244-251 waters of the Atlantic Ocean. @ 7990 Gemological Institute of America A 1970 survey estimated that there were about 3

244 Gem News GEMS & GEMOLOGY Winter 1989 Figure 1. The "orange flash" effect (left) noted in a filled break is no longer apparent after removal of the filling material (right) from the diamond. Photomicrographs by John 1. Koivula; magnified 15 X. billion carats of diamonds off the west coast of South Springs, Florida, allowed us to examine a most unusual Africa. Benguela Concessions has options on two con- star chrysoberyl (figure 3).The 1.54-ct stone, a translu- cession areas off the coast. A small-scale diamond cent greenish yellow oval cabochon, exhibited a strong, recovery operation near these two areas has extracted four-rayed star centered on the dome. Magnification 44,000 ct from the ocean over the past 11 years. (Dia- revealed that the asterism was due to the presence of mond Intelligence Briefs, Vol. 5, No. 91-92) densely packed, minute fibrous inclusions of unknown composition. COLORED STONES Burmese contract for new mining technology. Gold Update on hackmanite. The Summer 1989 Gem News mines in Myanmar (Burma]have contracted with Min, column reported on a faceted hackmanite and illus- Yugoslavia~sNis-based mining and metallurgical equip- trated the color alteration induced by exposure to long- ment company, to provide new mining equipment and wave ultraviolet radiation. Mrs. Wight, editor of technology needed to increase Burmese gold production. Experts speculate that this move by the Burmese could Figure 2. This unusual "adz~larescent" preface an opening of their gem resources. (Mining chalcedony is from. the Mojave Desert in Cali- Journal, Sept. 15, 1989). fornia. Photo by Shane McClure.

"Adularescent" chalcedony. Shane McClure of the G1A Gem Trade Laboratory in Santa Monica recently en- countered some unusual chalcedony (figure 2). The material, marketed as "Mojave Blue" by its discoverers Bill Nicks and Mike Pirtle of Bakersfield, California, is recovered from a desert location near the town of Mojave, north of Los Angeles in the Mojave Desert. The material has an appearance unlike anything we have previously seen in chalcedony. It ranges from semitransparent to translucent with a very light to medium grayish violet-blue body color. All the speci- mens we examined had a weak to distinct botryoidal structure. What is unusual about the material is a weak to quite distinct "adularescent" effect that in some instances mirrors the underlying spheroid structure. The effect was notably stronger than the sometimes hazy sheen seen in so-called chalcedony "." Microscopic examination revealed extremely fine, fi- brous inclusions which might produce a scattering of light that could account for the apparent body color and phenomenon.

Star chrysoberyl from Sri Lanka. Chrysoberyl is known to occur in two popular phenomenal varieties, cat's-eyes and color-change alexandrites. Jay Rosenthal of Coral

Gem News Figure 4. This carved psilomelane exhibits char- acteristic banding. Photo and carving by Bart I Curren. Figure 3. This unusual 1.54-ct cabochon is a rare example of star chrysoberyl. Courtesy of 1. Rosenthal; photo by Robert Weldon. Haineault from a pocket in the back wall of the Poud- rette Quarry at Mont Saint-Hilaire, Quebec, about 20 mi, (32 lim) south of Montreal, in the late summer of The Canadian Gemmologist, provided us with the 1988. Apparently, it is not unusual to find opaque, following information regarding this stone and its dis- whitish hackmanite at this locality, with the material covery. appearing "magenta" when first uncovered but fading on First, she reported that the weight of the stone is exposure to sunlight. The stone illustrated in the Gem actually 3.23 ct. The rough was recovered by Gilles News column was faceted from one of two large, transparent broken crystals found. These crystals cut Figure 5. Carved basalt as a gem material is be- approximately 40 stones in all, the largest weighing ing used in a variety of fashion items. Jewelry 15.33 ct. The same pocket that yielded the haclimanite designed by Valerie San Giacomo and Michael also produced pectolite and villiaumite specimens. Tope, Class Project Inc.; photo 0 Sky Hall. Among- the other unusual minerals collected from the Mont Saint-Hilaire locality are catapleiite, serandite, and light blue willemite.

Psilomelane and basalt: novel black carving materials. Recently a number of black gem materials such as hematite and dyed chalcedony have seen a resurgence in popularity in the form of carved stones in geometric and free-form shapes. In response to this demand for black gems, Bart Curren of Glyptic Illusions, Topanga, Califor- nia, began carving some materials not generally thought of as having gem application. One of these, psilomelane, is an oxide primarily of manganese with lesser amounts of barium and sometimes sodium and potassium to- gether with some water. It is usually found in botryoidal or stalagmitic form and has a Mohs hardness in the range of 5'/~-6~/2.Because of its mode of formation it often exhibits attractive banding, as can be seen in figure 4. Even more unusual as jewelry items were carvings made from basalt, a fine-grained igneous rock (figure 5). Examination of a thin section of the carving material

GEMS & GEMOLOGY Winter 1989 revealed the presence of some glass, in addition to plagioclase feldspar, augite, and olivine. This is the first time to our knowledge that basalt has been carved for use as an ornamental gem material.

Quench-crackled, dyed-green quartz. From time to time throughout history, rock crystal quartz has been quench crackled and dyed to imitate such gems as ruby and emerald. Timothy D. Schuler of Schuler Gemological Services, Palm Harbor, Florida, recently informed us that quartz that had been quench crackled and dyed green was being marketed in his area, mounted in 14K yellow gold ear studs, as "green amethyst." According to Mr. Schuler, customers were not being told that the material had been treated.

Huge, doubly terminated sapphire crystal. Mr. E. Gam- ini Zoysa, of the State Gem Corporation in Sri Lanka, reports the recent discovery of an extremely large, doubly terminated sapphire crystal (figure 6). Found in Figure 6. This 40.3-kg doubly terminated cor- Rakwana, the crystal weighs approximately 40.3 kg and undum crystal from Sri Lanka dwarfs the measures 25 x 50 cm (10 x 20 in.). According to Mr. pocket calculator used as a size reference. Zoysa, the crystal contains some good "gen~n~y"blue Photo courtesy of E. Gamini Zoysa. areas, as well as some areas that appear milky and may respond favorably to heat treatment. consider investing in gem-mining operations in their countries. Already, Laotian companies have established I' ' found in Burundi. Geologist and gem miner joint ventures with the Thais, including one operation Campbell I3ridges reports the discovery of a very large that is producing sapphires. Several other joint opera- new deposit of sapphire in Burundi, near the border with tions are expected to begin, and at least four of those Rwanda, The! deposit is said to be of volcanic origin. The include Australian interests. (Mining[ournal, Septem- material recovered thus far includes stones of good color ber 15, 1989; Mining Magazine, September 1989; [our- as well as some described as "geuda-type" which Mr. nal of Gem Industry, June 1989) Bridges feels will probably heat treat favorably. Large faceted Pamir spinel. A number of reports have Mining ventures are reactivated in Southeast Asia. After appeared in the literature recently about pink spinels years of war and economic hardship, Vietnam is gradu- coming from the Pamir Mountains in the Soviet Central ally implementing new policies to check inflation and Asian republic of Tadzhikistan [see Gem Trade Lab encourage international investments. The governn~ent's Notes, Spring 1989, pp. 39-40, and Zeitschrift der move to pull out of Cambodia and demobilize hundreds Deutschen Gemmologischen Gesellschaft, August of thousands of troops is expected to bring the country 1989, pp. 85-88). Recently a 146.43-ct intense reddish global recognition, most in~portantlyfrom the United pink brilliant was cut from a deformed crystal by Justina States. As a result, mining operations are beginning to re- Wright of Fallbrook, California. Mrs. Wright acquired open, particularly in the areas of metals and petroleum, the crystal from Marius Van Dylz. The rough also yielded Currently, small-scale operators are producing an esti- a 30.03-ct free-form. mated 1,000 kg per year of gold. Similarly, minor operators are reportedly considerable quantities Sri Lanka update. Gordon Bleclz recently returned from of "world class" rubies and sapphires in Ha Tuyen Sri Lanka with news of conditions that may adversely province. The Vietnamese government will work with affect the supply of gems from that country. He reports Thai interests in a joint venture to market these gems. that from January to mid-April of 1989 there was severe Experts say that the joint venture with the Thais is one drought and, in most mining areas, inadequate water to example of the Vietnan~esegovernn~ent's willingness to wash the gem gravels. Then, in June, the nation experi- open up to foreign investments and modernize their enced the worst flooding in 15 years, which stopped industrial sector. Furthermore, their receptiveness to mining in the central southern district for approx- joint ventures could lead to greater mining development imately one month. A significant increase in terrorist in this country. activity in June also led to decreased mining in outlying Elsewhere in the region, Laos and Cambodia have areas because miners were afraid to venture to the more asked the Thai Gems & Jewellery Traders' Association to remote mines.

Gem News GEMS & GEMOLOGY Winter 1989 247 Figure 7. This 3.55-ct zircon from Sri Lanka lacks the secondary brownish component often seen in green stones of this species. Courtesy of G. Bleck; photo by Robert Weldon. Figure 8. The color in this 8.77-ct hessonite is unusually saturated. Courtesy of G. Bleck; Mr. Bleclz also confirmed that approximately two photo by Robert Weldon. years ago emeralds were discovered at Hambantota, on the southeastern coast of Sri Lanka, in a former rice paddy. The emeralds are found under a layer of sandy soil tionally saturated orange color as well as a strong eye- about 2 ft. (72cm) below the surface, not far from the sea. visible "heat-wave" effect (figure 8)) which is typical of Reportedly about 2 kg of material has been recovered to hessonite from this classic source. date, but most of this is not gem quality. The largest stone faceted thus far weighs approximately 0.5 ct. The Paraiba tourmaline update. In the Fall 1989 Gem News color of the one crystal we examined was very saturated. column, we described some unusual tourmalines from In addition, Mr. Bleck reports examining a number of Paraiba, Brazil. These were notable for their color, unusual stones during his last trip, including a 3 + -ct ranging from bluish green to violetish blue. Since that light brown faceted monazite. The stone reportedly time, we have seen additional material from this locality came from the Trincomalee area in the northern part of that is light to medium in tone and yellowish green or the island. He also showed us a 40.91-ct piece of gem violet in hue. rough that could not be identified by gemologists who Recently, Dr. Emmanuel Fritsch, Meredith Mercer, examined it in Sri Lanka. The stone, which was recov- and Mike Moon of the GIA Research Department had an ered from a pit mine near Eheliyagoda, exhibited dark opportunity to analyze a range of Paraiba tourmalines blue and near-colorless areas. EDXRF spectroscopy, per- using EDXRF and UV-visible absorption spectroscopy. formed by GIA's Dr. Emmanuel Fritsch, identified the They found that the tourmalines contain manganese stone as cassiterite. However, we found no reference to and copper as possible coloring agents, along with traces either Sri Lanka as a source of cassiterite or its occur- of iron, The absorption spectra in the visible range of rence in blue in the current editions of Webster's Gems green to blue tourmalines from Paraiba are charac- and Liddicoat's Handbook of Gem Identification. terized by a broad band with an apparent absorption A new find of attractive green zircons was also maximum at about 700 nm. This band could be related reportedly made this past year, although the exact to either Fe2+ or Cu2+; oriented quantitative absorption locality has not been disclosed. The more than 20 stones measurements are necessary to ascertain its exact ori- we examined were primarily medium dark in tone and of gin. Less intense features attributed to Mn3+ (the main fairly high saturation, lacking the secondary brownish coloring agent of rubellite) have been recognized in some component generally seen in green zircons (figure 7). of the samples as well. The Paraiba tourmalines are They were also highly radioactive, registering about 60 therefore unique for their unusually high copper content times the level of background radiation. and their possible coloration by Cut+, which has not Another stone examined was an 8.77-ct triangular previously been encountered as a coloring agent in brilliant-cut hessonite garnet which had an excep- tourmalines.

248 Gem News GEMS &. GEMOLOGY Winter 1989 Figure 9. A- thin dark blue color zone on the base of this multi-colored tourmaline cabochon causes it to appear quite different in reflected (left) and transmitted (right) light. Stone courtesy of Crystal Kingdom, Venice, CA; photos by Robert Weldon.

Unusual multi-colored tourmaline. CIA librarian Ro- Figure 10. These two apparently waterworn cor- bert Weldon recently brought an unusual tourmaline undum crystals, 56.04 and 21.80 ct, are actu- cabochon to our attention. The 48.72-ct bullet-shaped ally flame-fusion synthetic sapphires. Photo stone reportedly came from somewhere in the vicinity of courtesy of the Swiss Foundation for the Re- the Turkish-Iranian border in western Asia. The tour- search of Gemstones (SSEF). maline showed a striking difference in appearance when illuminated with reflected versus transmitted light (figure 9). In reflected light, it exhibited a small area of oink at the tin. below which most of the stone avoeared slightly bluish green, with a very thin layer at the base that was almost black. When intense transmitted light was directed through the base, however, the majority of the stone took on a pleasing deep blue color, with some of the pink still visible in the tip. In transmitted light, the very dark blue color of the thin basal layer projected into the remainder of the stone. SYNTHETICS AND SIMULANTS Synthetic corundum "crystals." Dr. -Henry Hanni and Mr. George Bosshart, of the Swiss Foundation for the Research of Gemstones, recently issued an ICA Labora- tory Alert on two samples of synthetic corundum that were sold as waterworn rough (figure 10). The larger of the two weighed 56.04 ct, measured approxin~ately

Gem News GEMS & GEMOLOGY Winter 1989 249 Figure 12. These dark reddish brown inclusions were the only gemological evidence of the flux growth of the synthetic spinel crystal shown in Figure 11. Reportedly manufactured in the So- figure 11. Photomicrograph by John 1. Koivulci; viet Union, this 17.19-ct synthetic spinel crys- magnified 35 x . tal was flux grown. Photo by Robert Weldon. broken and waterworn [blue sapphire] pebble, showing 53.50 x 12.47 x 7.82 mm, and had a slight color change, one residual pseudo-crystal face with an irregular step- appearing purple in daylight and purplish red in incan- like relief." Concentric color banding, trace-element descent light. Its most interesting feature was its mor- analysis, and fluorescence to short-wave U.V radiation phology. It was described in the alert as having "a slender supported the identification of a flame-fusion synthetic barrel shape and irregularly spaced steps on the finely sapphire. frosted surface1' resembling a natural, waterworn bi- Neither the steps on the larger "crystal" nor the step- pyramidal purple sapphire crystal. Inclusions could not like elevations and depressions on the smaller one were be detected, even under in~n~ersion;its identification as parallel, and both appeared to have been produced by a a synthetic sapphire was based on a combination of the grinding wheel; the translucent, frosted surfaces dis- optic axis direction (approximately30' off the long axis), played by both specimens were believed to be the result size, color, and trace-element content. of tumbling or sanding. These two synthetic sapphires, The smaller "crystal" weighed 21.80 ct, measured fashioned to imitate natural crystals, had been pur- approximately 24.64 x 11.98 x 7.74 mm, and was chased recently in Sri Lanka. medium blue in color. It had the appearance of "a Flux synthetic spinel. The Gem News editors recently examined a 17.19-ct synthetic red spinel octahedron Figure 13, These fantasy cuts were fashioned (figure 11] that was brought to our attention by gemolo- from a new man-made material with a garnet- gist Bill Vance, who obtained it from a Soviet citizen. like structure called "Oolongolite." Photo cour- Although sold to Mr. Vance as a hydrothermal product, tesy of Dominique Robert. gemological investigation combined with infrared spec- trometry and EDXRF analysis proved it to be a flux- grown synthetic. All of the basic gemological properties were virtually identical to those of sin~ilarlvcolored natural spinel, with the exception of flux-like inclusions in one area of the crystal (figure 12). A stone cut from unincluded areas of such a crystal would not be identi- fiable by standard gemological tests. A 13.14-ct synthetic red spinel crystal with very similar properties was recently described by Professor Hermann Bank and Dr. Ulrich Henn of the German Foundation for Gemstone Research, ldar-Oberstein, in ICA Lab Alert No. 26, "Flux-Grown Synthetic Red Spinel from USSR."

New man-made crystal. GI& Dr. Emmanuel Fritsch reports that an apparently new man-made crystal with a garnet-like structure is now commercially available.

250 Gem News GEMS & GEMOLOGY Winter 1989 The material is produced and marketed by Dominique manufacturer are as follows: R.I. of 1.93 to 2.00, singly Robert of Lausanne, Switzerland, in a variety of cuts refractive, S.G, of 6.7 to 7.0, and Molls hardness of 7'12-8. including "fantasy1'-type carved gems (figure 131, under the trade name "Oolongolite." It comes in colorless, dark bllle, medium blue, medium green, dark bluish green, Acknowledgments: The editors would like to thank Jennifer and "lilac" hues. Gemological properties reported by the Rowland for her help in preparing this column.

The Art of Van Cleef & Arpels ors are represented, as are a variety Trade Fairs, Ltd., 9/F Sing-Ho Fi- nlakes its debut at the Los Angeles of cuts and locali tics. nance Building, 168 Gloucester County Museum of Art on April 7, Road, Hong Kong. Telephone: 1990. The exhibition features the The 8th Hong Kong Jewelry & 5-8335121; fax: 5-8345164. historical creations of the famed Fair will be held at the Hong jewelry company and will highlight Kong Convention & Exhibition Jewelex '90, the second Korea Inter- , , necklaces, ear- Centre September 17-20, 1990. At national Jewelry & Watch Fair, will rings, vanity and powder boxes, the 1989 fair, more than 1,500 be held September 20-24, 1990, at , evening bags, and special con~paniesfrom 30 countries were the Korea Exhibition Center in commissions dating from the 1920s represented, and more than 25,000 Seoul. The fair features the newest through the 1950s. After the ex- buyers from 60 countries attended. designs in jewelry and the latest hibit leaves Los Angeles on June The Hong Kong Fair will also give models of clocks, watches, manu- 17, the display travels to the Na- out eight awards to showcase the facturing equipment and accesso- tional Museum of Natural History, latest jewelry designs based on lies. For more information, contact Smithsonian Institution (July beauty, originality, wearability, the Korea Exhibition Center, 159, 12-Octobe~30],and the Honolulu adaptation to fashion trends, and Samsung-dong, Kangnam-la, Seoul, Academy of the Arts (January craftsmanship. For more informa- 135-731 Korea, Telephone: (02) 16-February 24, 1991). tion on the fair or how to enter the 551-5213; fax: (02)555-7414 or competition, contact Headway 551-1313. John Sinkankas's book Gem Cut- ting, originally published by D. Van The ruby petals in this peony clip, created by Van Cleef &> Arpels Nostrand Co. in 1955 and in 1936, illustrate the "invisible setting" for which the company is now in its third edition, was cho- noted; the stem and leaves are made of diamonds, sen by the Mir Publishing House of Moscow for translation into Rus- sian, under the title Handbook for Working Precious and Ornamental Stones, Mir published 70,000 copies in 1989. Gem Cutting is the first lapidary book to be translated into Russian and reflects the desire of the Soviet government to en- courage local artisans to take ad- vantage of the many gem deposits that occur throughout the Soviet Union.

The Aurora Gem Collection, one of the largest collections of "fancy" colored diamonds ever to be shown in public, is again on display at the American Museum of Natural His- tory in New York City. The collec- tion now consists of 244 diamonds with a combined weight of approx- imately 221 ct. Many different col-

Gem News GEMS & GEMOLOGY Winter 1989 251 Spring 1985 Summer 1985 ~ie~cicinolog: Back Issues of

Limited quantities of these issues are still available.

Winter 1983 Winter 1986 Engraved Gems: A Historical Perspective The Gemological Properties of the Sumitomo Gem- Gem Garnets Quality Synthetic Yellow Diamonds The Rubies of Burma: The Mogok Stone Tract Art Nouveau: Jewels and Jewelers Induced Fingerprints Contemporary Intarsia: The Medvedev Approach Cobalt Glass as a Lapis-Lazuli Imitation Spring 1987 Summer 1984 "Modern" Jewelry: Retro to Abstract Gem-Bearing Pegmatites: A Review Infrared Spectroscopy in Gem Identification Gem Pegmatites of Minas Gerais, Brazil: Exploration, A Study of the General Electric Synthetic Jadeite Occurrence, and Aquamarine Deposits A New Gem Material from Greenland: Iridescent The First-Order Red Compensator Orthoamphibole Fall 1984 Summer 1987 Freshwater Pearls of North America Gemstone Durability: Design to Display The Chemical Distinction of Natural from Synthetic Wessels Mine Sugilite Emeralds Three Notable Fancy-Color Diamonds: Purplish Identifying Gem-Quality Synthetic Diamonds: Red, Purple-Pink, and Reddish Purple An Update The Separation of Natural from Synthetic Emeralds Inclusions in Taaffeites from Sri Lanka by Infrared Spectroscopy Magnetic Properties of Gem-Quality Synthetic The Rutilated Topaz Misnomer Diamonds Fall 1987 Winter 1984 An Update on Color in Gems. Part I Natural Rubies with Glass-Filled Cavities The Lennix Synthetic Emerald Pyrope-Spessartine Garnets with Unusual Color An Investigation of the Products of Kyocera Corp. Behavior that Show Play-of-Color Gem-Quality Red Beryl from Utah Man-Made Jewelry An Extraordinary Calcite Gemstone Inamori Synthetic Cat's-Eye Alexandrite Green Opal from East Africa Winter 1987 Spring 1985 The De Beers Gem-Quality Synthetic Diamonds Gem Pegmatites of Minas Gerais, Brazil: The The History and Gemology of Queen Conch Tourmalines of the Araquai Districts "Pearls" Sapphire from Cauca, Colombia The Seven Types of Yellow Sapphire and Their Altering the Color of Topaz Stability to Light A Preliminary Report on the New Lechleitner Synthetic Ruby and Synthetic Blue Sapphire Spring 1988 Interesting Red Tourmaline from Zambia An Update on Color in Gems. Part 2 Chrysoberyl and Alexandrite from the Pegmatite Summer 1985 Districts of Minas Gerais, Brazil Pearl Fashion Through the Ages Faceting Large Gemstones Russian Flux-Grown Synthetic Emeralds The Distinction of Natural from Synthetic Gem Pegmatites of Minas Gerais, Brazil: The Alexandrite by Infrared Spectroscopy Tourmalines of the Governador Valadares District The Eyepiece Pointer Summer 1988 The Diamond Deposits of Kalimantan, Borneo Winter 1985 An Update on Color in Gems. Part 3 A Status Report on Gemstones from Afghanistan Pastel Pyropes A Proposed New Classification for Gem-Quality Examination of Three-Phase Inclusions in Garnets Colorless, Yellow, and Blue Sapphires from Sri Amethystine Chalcedony Lanka The Pearl in the Chicken Fall 1988 Spring 1986 An Economic Review of the Past Decade in A Survey of the Gemstone Resources of China Diamonds The Changma Diamond District, China The Sapphires of Penglai, Hainan Island, China Gemstone Carving in China: Winds of Change Iridescent Orthoamphibole from Wyoming A Gemological Study of Turquoise in China Detection of Treatment in Two Green Diamonds The Gemological Characteristics of Chinese Peridot The Sapphires of Mingxi, Fujian Province, China Winter 1988 Summer 1989 Gemstone Irradiation and Radioactivity Summer 1986 Amethyst from Brazil Complete your back The Coscuez Mine: A Major Source of Emeralds Opal from Opal Butte, Oregon The Elahera Gem Field in Central Sri Lanka A Gemological Look at Kyocera's Synthetic Star issues of i$$:: Some Unusual Sllllmanite Cat's-Eyes Ruby An Examination of Four Important Gems Gems & ~emology Green Glass Made of Mount Saint Helens Ash? Spring 1989 Fall 1986 The Sinkankas Library NOW! A Simple Procedure to Separate Natural from The Gujar Killi Emerald Deposit Synthetic Amethyst on the Basis of Twinning Beryl Gem Nodules from the Bananal Mine Single $ 8.00 ea, U.S. 'Opalite:" Plastic Imitation Opal Issues:' $11.50 ea. Elsewhere Pink Topaz from Pakistan Carbon Dioxide Fluid Inclusions as Proof of Natural- Summer 1989 Complete Colored Corundum Filled Diamonds Volumes: ' Specific Gravity-Origins and Development of the Synthetic Diamond Thin Films $26.50 ea. U.S. Hydrostatic Method Grading the Hope Diamond i:i; i:ii i:: Coiombage-Ara Scheelite Diamonds with Color-Zoned Pavilions 1988 full set 1$36-50 ea. Elsewhere 1986, 1987, and $65.00 U.S. 1988 full set $95.00 Elsewhere TO ORDER: Call: toll free (800) 421-7250, ext. 201 "10% discount for GIA Alumni Association members OR WRITE: GIA, 1660 Stewart Street, Santa Monica, CA 90404, Attn: G&G Subscriptions THE RETAIL New Yorlz at the Fifth Avenue shop of JEWELLER'S GUIDE Asprey & Co. 5th edition The boolz deals somewhat un- evenly with an interesting and sadly By Kenneth Blakemore, 412 pp., il- BOOK neglected period in jewelry history. l~,publ. by Butterworths, Great Beginning in 1848 with the forma- Britain, 1988. USS49.95 * tion of the Pre-Raphaelite Brother- Blaken~ore'sbook is intended to ac- hood-a group of artists whose de- REVIEWS- --- - quaint the reader with most aspects signs related directly to their roman- I B, of the retail jewelry business. Ten Elxe Misiorowslzi and tic private lives-it carries through Loretta B. Loeb, Editors chapters cover the basics for precious J1 to the end of the 19th century and the metals, gemstones, antique jewelry Arts and Crafts Movement. Insofar and silverware, hallmarks, modern as their jewelry designs were con- jewelry n~alzing,silversnlithing, and cerned, the artists of this period were horology both past and present. For Blalien~orecould also have taken most interested in symbolism, ro- this fifth edition, two new chapters- the time to update his section on mantic associations, and secret on glassware and -have been diamond grading. Only the CIBJO meanings. It was a fascinating era of added, prompted by the giftware de- categories for color and clarity are passion and intrigue, and perhaps partments now in many jewelry listed, while GIA, AGS, and ScanDN this boolz will stimulate additional stores. Blakenlore has also added up- grading systems are represented by scl~olarlyconsideration. dated information on hallmarking in vague and, in GIA's case, incorrect The authors have made a judi- Holland, Portugal, and the United descriptions. It would have been cious selection of spectacular jewelry Kingdom to reflect recent changes in clearer and more equitable if the with many original design render- legislation. The last 50 pages provide author had simply printed a chart ings, paintings, and photographs of six glossaries relating to jewelry, con~paringall four systems. the period to place the jewels in their gemology,, -.horology, and giftware, This book contains a lot of use- proper socio-historical perspective. along with five appendices that cover ful inforn~ation.Unfortunately, its The illustrations are both numerous such topics as "Exemptions from uneven character undermines confi- and handson~e,there is a useful in- Hallmar1iii~g1'and "Touchstone Test- dence in the booli as ;i whole. How- dex, and the booli feels conlfortable ing in the Workshop." The booli is ever, the reader should keep in mind in the hand. The graphics, in fact, well structured and generally infor- that, as the title states, this is simply carry the day. The authors, although mative, but it is somewhat out of a guide for retail jewelers and not the respected and frequently published balance. Where some of the sections last word on the subject. authorities in the field, have a writ- are covered in depth (antique silver- COS ALTOBELLI ing style that often obscures, rather ware, jewelry from the Reni't issance Altobelli Jewelers than clarifies, the subject. A tremen- through the 19th century), others North Hollywood, CA dous amount of research was obvi- (gemology, 20th century jewelry) are ously undertaken, but it is pon- given only superficial treatment. derously presented. The bewildering In his preface to this new edi- text contains sentences that run to tion, Blakemore states that he has ARTISTS' JEWELLERY: almost a hundred words, leaving the updated the gemology chapter to PRE-RAPHAELITE TO reader exhausted and unsatisfied. cover new developments in the field. ARTS AND CRAFTS Perhaps the fault lies more with the However, the section on synthetics is editors than with the writers, but already out of date in that no men- By Charlotte Cere and Geoffrey C. even with all its virtues the booli tion is made of either the Russian Munn, 244 pp., illus., publ. by The somehow fails to live up to the ex- hydrothermal synthetic emeralds or Antique Collectors' Club, Wood- citement and charm of the subject. the Sumitomo synthetic diamonds, bridge, Suffolk. U.K., 1989. USS69.50* NEIL LETSON both of which were discussed in the New York, NY literature before this edition went to This book was produced as a pendant print. He also states that in 1974 a to a splendid exhibition mounted in parcel of blue topaz faded con~pletely, London by the firm of Wartski, and although the current literature was sold to persons attending the 'This book is available lor purchase at agrees that the color of treated blue show and a number of charity eve- the GIA Bookstore, 1660 Stewarl Street, topaz is stable unless heated to nings with Royalty present. A more Santa Monica, CA 90404. Telephone: 5OO0C. recent exhibition was also held in (800) 421 -7250, ex!. 282.

Book Reviews GEMS & GEMOLOGY Winter 1989 253 GEMOLOGICAL ABSTRACTS

Dona M, Dirlam,Editor

REVIEW BOARD

Barton C. Curren Gary S. Hill Elise B. Misiorowski Topanga Car~yon,California GIA, Santa Monica GIA, Sanla Monica Stephanie L, Dillon Karin N. Hurwit Gary A. Roskin San Clemente, Calilornia Gem Trade Lab, Inc., Sanla Monica GIA, Santa Monica Bob F. Effler Robert C. Kammerling James E. Shigley GIA, Santa Monica GIA, Santa Monica GIA, Santa Monica Emmanuel Fritsch Neil Letson Carol M. Stockton GIA, Santa Monica Palm Beach, Florida Los Angeles, Calilornia Patricia A. S. Gray Shane F. McClure William R. Videto Bangkok, Thailand Gem Trade Lab, Inc., Santa Monica GIA, Santa Monica Mahinda Gunawardene Robert Weldon Idar-Oberstein, Germany GIA, Santa Monica

COLORED STONES AND uncommon in apatites that occurr in igneous rocks. ORGANIC MATERIALS Electron microprobe analyses indicate BaO values up to Barium- and strontium-enriched apatites in lamproites 12.5 wt.% and SrO values up to 5.8 wt,%.Both elements from West Kimberley, Western Australia. A. D. are thought to substitute for Ca in the apatite crystal Edgar, American Mineralogist, Vol. 74, No. 718, structure. Ideas on the genesis and crystallization of the 1989, pp. 889-895. apatites and their host lan~proitesare presented. /ES Because lamproites are now recognized as an important The characteristics of Burmese spinel. T. Hlaing, Austra- host rock for diamonds, their mineralogy and chemistry lion Gemmologist, Vol. 17, No. 3, 1989, pp. 84-87. represent an important field of study. Lamproites from the West Kimberley area of Australia contain apatites This report, part of the author's master's thesis, covers that are enriched in BaO and SrO. Both elements are the gemological, mineralogical, and chemical properties of spinel from the Mogok region of Burma. Examination of crystals revealed that most are well formed or only slightly distorted. Statistically, about 70% of those This section is designed to provide as complete a record as recovered are considered too small to facet, with crystals practical of the recent literature on gems and gemology. Articles are selected for abstracting solely at the discretion of the section between 0.40 cm and 0.90 cm being fairly common. editor and her reviewers, and space limitations may require that we For the 13 specimens examined, refractive index include only those articles that we feel will be of greatest interest to ranged from 1.714 to 1.730 and specific gravity ranged our readership. from 3.477 to 3.721. S.G. increased with Fe, Mg + Fe, or Inquiries for reprints of articles abstracted must be addressed to Mg + Cr content. Spectrochemical analysis showed that the author or publisher of the original material. the depth of color in red spinel correlates with increasing The reviewer of each article is identified by his or her initials at the chromic oxide content. A comparative study of the end of each abstract. Guest reviewers are identified by their full trace-element content of red spinels from Mogok, Sri names. Opinions expressedin an abstract belong to the abstracter Lanlza, and Hunza (Pakistan) revealed a significantly and in no way reflect the position of Gems & Gemology or GIA. higher chromium content in the Mogolz material. The article includes a number of charts and tables of 63 1990 Gemoloqical Institute of America data to support the author's conclusions. RCK

254 Gemological Abstracts GEMS & GEMOLOGY Winter 1989 Dayboro . G. Brown, Australian Gemmologist, light brown material is isotropic, stress-induced bire- Vol. 17, NO. 3, 1989, pp. 98-100. fringence can be observed with crossed polarizing filters. This report begins with a review of the sonletimes Refractive index and density values of 1.462-1.467 and confusing literature describing an aluminum phosphate 2.241-2.270, respectively, fall within the ranges for n~ineralfrom the Dayboro deposit, located 40 kn1 north- glasses. SEM micrographs of this material showed the northwest of Brisbane, Queensland, Australia. The de- n~inutelayers that provide the interference phenome- posit, on the summit of a low hill, occurs in a thinly non. Electron microprobe analysis revealed a conlposi- bedded brecciated black chert. Most of the material tion that, while silicon-rich, includes sufficient minor occurs as an intimate intergrowth of variscite with elements to identify the material as a glass rather than quartz; slabbed surfaces of the chert randomly opal. This conclusion was supported by X-ray diffraction scattered nodular masses and veins of variscite. Cab- analysis, which indicated amorphous structure; by in- ochons of the variscite often contain various amounts of frared spectroscopy, which showed a lack of water; and the host matrix. by thermogravimetry, which revealed a reaction inconsis- Gemological investigation of the variscite revealed tent with opal. The authors thus conclude that this the following properties: opaque with a bluish green material is a natural glass, possibly formed from late- color, 1.56 spot R.I., waxy luster, chalky green fluores- magmatic vapors, steams, or aqueous solutions depos- cence to long-wave U.V and inert to short-wave U.V, no ited in rhythmic layers. This article is well illustrated diagnostic visible-light absorption features, S.G. of 2.4 to with photographs, photoinicrographs, micrographs, and 2.5, Mohs hardness of 4, and an uneven fracture. analytic graphs. CMS The author concludes that the Dayboro variscite has more historic than economic significance and that the New data on the cause of smoky and amethystine color distinctive matrix may help in determining the prove- in quartz. A. J. Cohen, Mineralogical Record, Vol. nance of the material. R CK 20, No. 5, 1989, pp. 365-367. This informative article puts in perspective the inter- Flame-like markings on the surface of conch pearl [in relationship betweeh the amethystine and smoky colors Japanese]. H. Komatsu, J. Yazaki, and Y. Matsuda, in quartz. When the aluminum impurity (Al3*) substi- Hos,e& Gakkai Si, Vol. 11, No. 1-4, 1984, pp. tuting for silicon is in large excess compared to the 30-3 1. interstitial Fe3+ impurity, natural radioactivity will The conch, "pearl," a type of calcareous concretion turn the quartz a smoky color. The color center is a produced by the giant conch (Strombiis gigas), often has missing electron (hole) on an oxygen bound to the flame-like markings 011 its surface. In this article, the aluminum atom.

authors attempt todetermine the cause of this peculiar Inversely, when the interstitial Fe3 + is more abun- marking by studying the structure of the internal dant than the Al3+, the amethystine color appears after surface layer of this animal's shell irradiation. The color is due to an Fe4+ ion, stabilized by When examined with an optical microscope (40x ), charge transfer with the Al-trapped hole. Therefore, the the internal surface of the shell showed a striped pattern presence of Fe3+ protects against the formation of similar to the "flame" of the conch "pearl." This pattern, "smoky" color centers. Smoky quartz can also be turned however, could not be observed with a scanning electron amethystine in color, although only temporarily, by microscope, which indicates that the pattern is visible cooling to liquid nitrogen temperature or below. Appar- only when light penetrates the surface layer of the ently, Fe3+ or Fez+ atoms, by losing one or two electrons, specimen. respectively, form Fe4+ and bring about the amethystine The authors then exanlined the various sections of color regardless of the A1:Fe ratio.

the surface layer. They observed rows of thin aragonite The presence of Fe3 +- in channels perpendicular to crystals forming one block, with each adjacent block the major rhombohedron produces Brazil-law twinning intersectingat a certain angle. Because of this angle, two to relieve the strain in the quartz structure. Such adjacent reflected light beams, with different rates, channels do not exist perpendicular to the minor rhom- create the striped pattern. The authors concluded that bohedron, which does not show such twinning. Twinned the flame-like markings on a conch "pearl" are directly zones are often of amethystine color, or, if they are related to the striped pattern on a flat surface of a shell. yellow, they can be turned amethystine by irradiation; Six photographs and one drawing illustrate the features untwinned zones might not change color. EF described. Himlko Naka Iridescent natural glass from Mexico. H. A. Hanni, Pink corundum is ruby. Jewellery News Asia, No. 59, Journal of Gemmology, Vol. 21, No. 8, 1989, pp. July 1989, pp. 1, 28, 32. 488-495. Pink corundunl is now to be called ruby, according to the "Iris opal" from San Luis Potosi exhibits spectral colors International Colored Gemstone Association (ICA), caused by optical interference. Although the transparent based on a vote taken at the association's third biennial

Gemological Abstracts GEMS & GEMOLOGY Winter 1989 255 congress held in May 1989 in Sri Lanka. The ICA the colors of the samples: Micro-striae and rutile needles members from Asia were unanimous in their support of correlate with fine blue hues, while hematite occurs in this change, noting that consumer confidence was being conjunction with darker colors. Thread-like needles of eroded in Japan when a stone purchased as a ruby was rutile formed the silk present in all samples. Several determined to be pink sapphire by a lab. On the other other inclusions were observed, among them: tube-like hand, a number of U.S. and European members voted primary cavities filled with scaly aggregates of iron against the change, stating that pink sapphires already hydroxides or oxides; transparent birefringent crystals have high recognition and demand in the U.S. One fear is that revealed a tabular hexagonal shape and chemical that if pink sapphires were now to become fair rubies, composition consistent with corundum; and reddish prices would drop. Thai delegates argued that the term brown prismatic idiomorphous crystals that consist of pink sapphire was introduced only recently and reflects titanium oxide, suggesting rutile or brookite. Also the problem of linguistic differences between the Thai observed were feathers of minute inclusions composed language and English. In Thai, there is no separate word of Al andlor Ti, as well as healed fractures filled with a for lighter tones of red, which are called pink in English. fluid and, sometimes, yellow or brownish red iron Yianni Melas hydroxides or oxides. Color photographs and photo- micrographs illustrate the features discussed. CMS OH substitution in garnets: X-ray and neutron diffrac- tion, infrared, and geometric-modeling studies. Structural variations in natural F, OH, and Cl apatites. G. A. Lager, T Armbruster, F. J. Rotella, and G. R. J. M. Hughes, M. Cameron, and K. D. Crowley, Rossman, American Mineralogist, Vol. 74, No. American Mineralogist, Vol. 74, No. 718, 1989, pp. 718, 1989, pp. 840-851. 870-876. This study was undertaken to understand better the As with any gem mineral, the gemological properties of nature and extent of OH substitution in natural garnets. apaties are closely related to the chemical con~position Three titanian andradites and a synthetic hibschite were of the material. Natural apatites of composition investigated. Details of the crystal structures of these Cae(P04)i(F,0H,Cl)exhibit large variations in F, Cl, and samples are presented. According to the authors' data, OH contents. This article reports the results of a crystal- OH substitutes for Si4+ in the tetrahedral site. Infrared structure refinement study of near-end-member speci- absorption spectra indicate the amount of structurally mens of each of these three compositional varieties. bound water (as OH-) to be between 0.8 and 5.7 wt.% These three ions (F-,Cl-,OH-) occupy slightly differ- OH. The geologic implications of the occurrence of ent positions within the anion site in the crystal water in garnets in the mantle are also discussed. JES structure, but this has little effect on the positions of the other constituent atoms. However, these minor struc- tural differences suggest that the three end members are Star sapphire from Kenya. N. R. Barot, A. Flainini, G. immiscible in solid solution. Therefore, one might Graziani, and E. J. Gubelin, Journalof Gemmology, expect a continuous variation in some gemological Vol. 21, No. 8, 1989, pp. 467-473. properties with changes in composition. IEs In 1987, star sapphire from Kenya began to appear on the market in comn~ercialquantities and qualities. The DIAMONDS material reportedly comes from sedimentary topsoil of the desert-like plains of northwest Kenya near the Mantle-derived fluids in diamond micro-inclusions. 0. Ethiopian border, although the primary source has not Navon, I. D. Hutcheon, G. R. Rossman, and G. J. yet been located. The 10 cut specimens studied by the Wasserburg, Nature, Vol. 335, No. 6193, October authors include various tones of blue, greenish blue, 27, 1988, pp. 784-789. greenish yellow, and dark brown body colors, with six- or The authors studied six cubic and nine coated diamonds 12-rayed asterism of various strengths. from Zaire and Botswana for the numerous sub- Optical microscopy and electron microprobe anal- micrometer, subrounded inclusions found in their fi- ysis revealed the presence of a number of different types brous zones. The study of these inclusions gives impor- of inclusions in the study specimens. Cloudy areas were, tant indications on the environment of diamond forma- in at least some cases, caused by parallel striae possibly tion. The diamonds in this report were grayish brown to related to lamellar twinning. Color zoning was observed green to yellowish green; the yellow color of many of the with straight or angular edges. Two types of acicular coatings was attributed to their type Ib character. inclusions that contribute to asterism were identified: The microincl~isionsstudied differ in composition micro-striae similar in composition (according to elec- from the more common large inclusions found in clia- tron microprobe analysis] to the host sapphire and mond, such as garnet, olivine, and pyroxene. As a whole, resulting from alternating growth and temperature vari- though, the chemistry of these microinclusions is ations; and larger needles of, possibly, hematite and broadly similar: rich in SiO,, K20, CaO, and FeO. They rutile. All three acicular inclusions also contribute to apparently also contain a mixture of heavily hydrated

256 Gemological Abstracts GEMS & GEMOLOGY Winter 1989 clay minerals, carbonates, phosphates, and sonletimes in nitrogen aggregation between E- and P-type diamonds, nlolecular CO,. This chemistry resembles that of po- but there was one between the two locations: The Finsch tassic magmas, from which diamond-containing rocks produces diamonds with more nitrogen in B aggregates such as kimberlite and lan~proitecrystallize. However, than the Premier. One of the groups of diamonds of very the inclusions are also enriched in water, carbonate, similar nitrogen concentration, 13C ratio, and mineral potassium, and magnesium, indicating that they formed inclusion composition may be common to the two during the growth of the diamond from trapped fluids mines, indicating a possible common origin for some that may have been remnants of a volatile-rich fluid or diamonds of the two lzimberlites, but different subse- melt from the upper mantle in which diamond grew. The quent histories. The authors conclude with a discussion authors conclude with two possible scenarios for the of the nitrogen content of diamonds as controlled by the growth and emplacement of microinclusion-bearing local nitrogen concentration, the temperature, the avail- dianlond. EF ability of chemical forms that favor the incorporation of nitrogen in the crystal, and, finally, by the oxygen Mechanism of self-diffusion in diamond. J. Bernholc, A. fugacity. EP Antonelli, T M. Del Sole, Y. Bar-Yam, and S. T Pantelides, Physical Review Letters, Vol. 61, No. GEM LOCALITIES 23, 1988, pp. 2689-2692. The Brazilian emeralds and their occurrences: Carnaiba, In this article the authors describe theoretical calcula- Baliia. D. Schwarz and T Eidt, Journal of Gemmol- tions that show that the diffusion of intrinsic defects in ogy, Vol. 21, No. 8, 1989, pp. 474-486. the diamond structure is dominated by the vacancy mechanism, independent of the number of electrons at The Carnaiba emerald region was discovered in 1963 the defect. The dominance of this mechanism is due to and, until the discovery of Santa Terezinha in 1981, was the stiffness of dian~ondbonds, which precludes twist- the most important source of emeralds in Brazil. Produc- ing or large deformations, and the great electronic tion for Carnaiba has been increasing in the 1980s, but density, which causes large repulsive forces for self- systematic exploitation with modern mining tech- interstitial defects, an alternate possibility for diffusion. niques will soon be required if the deeper deposits are to This explaids why the vacancy is the lowest energy be exploited. The authors discuss the local geology and defect in diamond, and also why there is a lack of provide geologic maps of the two major occurrences at annealing of, grain boundaries in polycrystalline thin- Carnaiba and Socot6. Emeralds occur as aggregates and film diamond. The migration energy calculated for the single crystals in a mica-schist rock, with associated GR1 center, 1.9 ey agrees well with that measured minerals that include molybdenite, quartz, apatite, experin~entallyby another team, lending support for the schorl, alexandrite, pyrite, etc. Emerald mineralization identification of the GRI center as a vacancy. in this region is consistent with that observed elsewhcre, Difficulties in the growth of synthetic single-crystal and is related to zones of strongest tectonic activity. diamond films have arisen as a result of mechanisms The authors provide microprobe analyses of six that involve migration of atoms in the structure. The samples that show typical compositions. The low trans- authors' calculations indicate that the use of dopants parency of most of the emeralds studied was due largely such as boron could help produce the desired growth. to "flocs" and "stars": minute one- or two-phase inclu- EF sions clustered in agglomerations of various compact- ness. Larger multi-phase inclusions also occur. Other Nitrogen and 13C content of Finsch and Premier dia- mineral inclusions are rare and consist largely of biotite1 monds and their implications. l? Deines, J. W phlogopite mica in plate-like and lath-like forms. Mus- Harris, l? M. Spear, and J. J. Gurney, Geochimica ei covite and chlorite also occur, as do tourn~aline,albite, Cosmochimica Acta, Vol. 53, 1989, pp. and a number of other occasionally observed minerals, 1367-1378. Chemical analyses of feldspar, phlogopitelbiotite, and Nitrogen content and state of aggregation were deter- muscovite inclusions are presented as well. mined using infrared spectroscopy for diamonds from Growth features were observed in the form of the Finsch (93 samples) and Premier (116 samples) concentric striation visible when looking down the lzimberlites in South Africa. The authors observed that c-axis, growth pyramids forming zig-zag lines, and the nitrogen concentration ranged from 7 to 1639 ppm. growth striae or layers parallel to both the basal face and Most of the study diamonds with ultramafic or peridoti- the prism faces. A number of excellent and informative tic (P-type)mineral inclusions contained generally less photomicrographs accompany the article. CMS than 100 ppm nitrogen, whereas diamonds with eclogi- tic (E-type)inclusions had nitrogen contents anywhere Yundamindera 'fire' opal. G, Brown and H. Bracewell, between 0 and 1200 ppm. In both of the lzimberlites, Australian Gemmologist, Vol. 17, No. 3, 1989, pp. nitrogen-free type I1 diamonds very rarely contained 101-103. eclogitic inclusions. There was no significant difference Yunclaniindera Station, 640 kin east-northeast of Perth

Gemological Abstracts GEMS & GEMOLOGY Winter 1989 257 in Western Australia, was first revealed as a source of fire Mourning jewellery. J. C. Birn~ingham,Australian Gem- opal in a 1903 survey report. Gem-quality material has mologist, Vol. 17, No. 3, 1989, pp. 82-84. been recovered from several vertical pits over eight This brief, interesting article traces the historic use of decades, and good-quality material can still be found in mourning jewelry. Early examples include Greek and abandoned mines or their tailings. Roman cameos that portraved commemorative scenes of The material from this deposit is described as being men and gods, and burial rings that were either engraved a type of "comn~onopal" in that it displays no play-of- or inlaid. Mourning jewelry during Medieval times was color. The authors examined some recently recovered usually in the form of rings and made accord- specimens, the finest of which ranges from transparent ing to the will of the deceased. Mourning jewelry in to translucent with a "rich amber" to "reddish amber" Tudor England is described as large, heavy, and ornate, color that is almost identical to some Mexican fire opal. while the Memento Mori jewelry of the 17th century It has a 1.42 R.I. and a resinous luster; is inert to long- included the use of rather gruesome images of sliulls, and short-wave U.V radiation; exhibits no diagnostic skeletons, and coffins. Eye portraits, depicting just the absorption features; has a hardness of 5 to 5'12, a eye of the loved one painted on ivory, date from the conchoidal fracture, and an S.G. of 1.98 to 2.00. Micro- Regency Period of the late 18th century. jewelry and scopic exan~inationrevealed flow structures, dark den- hair jewelry, often thought of in connection with mourn- dritic inclusions most likely caused by epigenetic infil- ingperiods, date from the early 1800s in England; the use tration of fractures, and vein-like internal structures. of jet became more fashionable after the death of Prince The report is nicely illustrated in color with locality Albert, when Queen Victoria allowed only black to be photographs, macrophotographs, and photomicrographs. worn at court. This was followed by a period of "half- R CK mourning," when women were allowed to wear gray, mauve, or purple, and amethyst and garnet replaced jet. RCK INSTRUMENTS AND TECHNIQUES Practical goldsmithing: Hinged sections. A. Some inexpensive improvements to existing instru- Revere, Jewelers' Circular-Keystone, Vol. 160, No. ments. C. Lewton-Brain, fournal of Gemmology, 8, August 1989, pp. 432-438. Vol. 21, No. 8, 1989, pp. 500-505. The use of hinges is extensive in the jewelry industry. In The author describes a number of inventive low-cost this article, Alan Revere demonstrates the fabrication adaptations to his gemological testing equipment, includ- and assembly of a series of bracelet sections, focusing on ing a homemade polariscope, a dual-lens arrangement to the cradle, or 's, hinge. The clear and precise improve spot readings on a refractometer, and an align- descriptions, along with photos and a diagram of dimen- ment wire to improve the accuracy of readings from an sions, provide a lucid and concise picture of what is S.G. balance. Drawings and photos illustrate the equip- required to perform the task. Matthew Bezak ment described. CMS Philippe Wolfers: Master of Art Nouveau. K. Alzkerman, JEWELRY ARTS Jewelers' Circular-Keystone: Heritage, Vol. 160, Collectible watches: An introduction. H. B. Fried, Jew- No. 8, August 1989, pp. 162-170. elers' Circular-Keystone:Heritage, Vol. 160, No. 8, At the turn of the century Belgium was an important August 1989, pp. 172-181. European cultural center, especially in the development This article is directed toward the new collector of of Art Nouveau. Alikerman focuses here on one of the antique watches. Because scarcity is a key factor for most notable Art Nouveau jewelers in Belgium, Philippe collectibles, one should look for watches that represent Wolfers. limited production runs or contain certain unique fea- Born to a wealthy family of court jewelers, Philippe tures such as skeletonized n~ovementsor unusual es- studied art before he apprenticed with the family firm. capements. I11 addition, there are four grades for watch His interest in nature, as well as in Eastern and Renais- quality: mint, near mint, fine, and fair. Fried also issues sance art, can be seen in the exotic and hauntingly cautions about clever reproductions that can fool a beautiful jewelry that he began to produce in the early novice, and tells how two famous (Tom- 1890s. pion and Breguet) dealt with and guarded against forg- Alilierman discusses some of the distinctive charac- eries. teristics of Philippe Wolfers's jewels, and gives examples The horological editor for JCK, Fried concludes this of the different hallmarks that identify his work. He also article with the offer of a readers' service. This service compares this work with that of some of Wolfers's gives JCK subscribers the chance to obtain information contemporaries. as to identity age, rarity, and history (butnot price!) of a Wolfers kept a careful catalog of his one-of-a-kind particular watch. Many photos and a list of recom- jewels, and several of these pieces are described and mended reading accompany the text. E BM illustrated. Although Wolfers designed each piece and

258 Gemological Abstracts GEMS & GEMOLOGY Winter 1989 supervised its making, several craftsmen were involved. deposition. A. T. Collins, M. Kamo, and Y. Sato, Credit is given to some of his skilled enamelists as well. journal of Physics: Condensed Matter, Vol. 1, There is a lot of information in this well-researched 1989, pp. 4029-4033. article, but it simply whets our appetite for Alzlzerman's The authors describe the cathodolurninescence of some forthcoming book on this talented goldsn~ith.Color single-crystal diamonds grown by microwave-assisted photographs of Wolfers's exquisite jewelry accompany chemical vapor deposition (CVD).From the observation the article. EBM of intrinsic edge emission, they conclude that the crystals with very low (

Gemological Abstracts GEMS &. GEMOLOGY Winter 1989 259 gence of 0.008-0.009. Other properties included: uniax- to have the following properties: vitreous luster, an R.I. ial negative; strong pleochroism of slightly bluish green of 1.73, singly refractive, inert to U.V radiation, green and slightly greenish blue; no Chelsea filter reaction; through the Chelsea filter, no visible diagnostic absorp- inert to both long- and short-wave U.V radiation, with no tion features, a hardness of 5 to 5'12, three directions of white-light transmission luminescence; and an S.G. of cubic , parallel parting planes (detected in thin 2.71 to 2.84. sections between crossed polars), and an S.G. of 3.57. Immersion microscopy revealed a number of key With n~agnification,a faceted stone cut from a piece of features: partially healed fractures composed of two- the rough revealed internal cleavage and what appeared phase inclusions; tapering two-phase "dagger" inclu- to be a gas bubble; the surface showed oriented drag sions; phenakite crystals; parallel, somewhat flattened marks which further confirmed its softness. wavy growth banding that was frequently intersected by On the basis of their examination, the authors what are described as "arrowhead," "spear," or "quill- determined the material to be synthetic periclase, possi- like" growth features; and small groups of brassy clus- bly doped with iron. They later learned that the material ters of acicular metallic crystals. had been produced in Austria '"by subjecting pure The authors conclude that while the gemological n~agnesiunlcarbonate to an unspecified electrofusion properties of these hydrothermally grown synthetic process.'" A final observation by a cutter who worked emeralds mimic those of some natural emeralds, their with the authors was that after several months the characteristic inclusions will positively identify them polished surface of the rough became increasingly dull as synthetic. RCK and eventually was coated with a whitish efflorescence of brucitef?],a common alteration product of periclase. RCK Some observations on Helenite. G. Brown and J. Snow, Australian Gemmologist, Vol. 17, No. 3, 1989, pp. Tracht and habit of synthetic minerals grown under 88-90, hydrothermal conditions. W A. Franke, European The authors detail their investigation of two types of Journal of Mineralogy, Vol. 1, No. 4, 1989, pp. green glass claimed to be produced from Mount St. 557-566. Helens volcanic ash and sold under the name "Helenite." Franke summarizes the variations in tracht (thevarious One type, described in the vendor's literature as "pure crystal faces present) and habit (the relative proportions melted ash" glass, was semitransparent, had an S.G. of of those faces) of synthetic minerals grown under hydro- 2.51, an R.I. of 1.51, exhibited a conchoidal fracture and a thermal conditions. For silicates and oxides, crystal vitreous luster, was inert to both long- and short-wave morphology is very dependent on the temperature of ultraviolet radiation, and was warm to the touch. Magni-- formation: With increasing temperature, an increasing fication revealed a concentric lamellar structure, flow number of faces enter the crystal shape and the habit structures, stretched gas bubbles, and both small masses tends to get more isometric. Supersaturation or volun- and smaller grains of grayish volcanic ash-like material. tarily introduced impurities havelittle influence. This is The gas bubbles and flow structures were oriented at illustrated in particular by corundum, which is tabular right angles to the concentric layers. when grown at 600° and almost equant at 800°CThe The second type was sold as "ash diluted by glass." It author also discusses alkali feldspars and carbonates. was transparent and had an S.G. of 2.53 and an R.I. of Over 20 crystal drawings illustrate the observations. 1.526. Its fracture, luster, reaction to U.V radiation, and EF feel were identical to those of the other type. Magnifica- tion revealed a less obvious concentric lamellar struc- MISCELLANEOUS ture, no unmelted ash-like material, rounded gas bub- Illuminating the Maya's path in Belize. N. Epstein, bles, and irregular, unoriented swirl striae. Smithsonion, Vol. 20, No. 9, December 1989, pp. From these data the investigators draw a number of 98-1 13. interesting concl~~sions.The small grains of ash-like Archaeologists Diane and Arlen Chase discuss their material supported the claim that the first type did discoveries of the Maya site called Caracol in Belize. contain at least some Mount St. Helens volcanic ash. Caracol, which means snail, in Spanish, refers to the RCK site's location at the end of a logging road in the rain forest. The Chases detail this site; the Mayan activities Synthetic periclase. S. M. B. Kelly and G. Brown, during the Classic, Middle Classic, and Late Classic Australian Genimologist, Vol. 17, No. 3, 1989, pp. eras; the Mayan system of warfare; ancl the design of the 90-92. city ancl its northern neighbor Tikal. Brief mention is After briefly reviewing the properties of both natural and made of the jade jewelry found in 1986 in the tomb of a synthetic periclase as described in the literature, the woman dated from the Classic period. Epstein concludes authors report on their own examination of some trans- by mentioning plans of the Belizian government to parent, slightly greenish yellow material brought to one incorporate Caracol into a national park which will take of them for identification. The material was determined in the surrounding rain forest. Rose Tozer

260 Gemological Abstracts GEMS & GEMOLOGY Winter 1989 Index Volume 25 Numbers 1-4, 1989

SUBJECT INDEX This index gives the first author (in parentheses) and first page of the article, Editorial Forum [EF), Gem News (GN),or Gem Trade Lab Notes (GTLN) section in which the indexed subject occurs. The reader is referred to the author index for the full title and the coauthors, where appropriate, of the articles cited. The pages covered by each issue are as follows: Spring (1-661, Summer (67-128)) Fall (129-194)) Winter (195-265). A Azurite-malachite World Map of Gemstone Deposits Almandine reconstructed [GN)45 [Gubelin) 185 from Orissa, India [GN)45 Brazil star, from Idaho [GN)45 B aquamarine from Ponto de Amber simulant Basalt Marambaia (GN)177 plastic [GTLN)236 as carving material (GN)244 bicolored from Bananal Amethyst Benitoite * mine [Kampf) 25 correction .in Epstein article [EF) Smithsonian, provenance of emeralds from Capoeirana, Minas 109 6 [EF)42 Gerais (Epstein) 150 from ~iik(GN) 177 Berlinite, synthetic tourmaline from Paraiba (GN)177, sceptors from Malawi [GN)177 with bull's-eye optic figure (GN) (GTLN)236, [GN)244 Amethyst-oitrine 110 from Bolivia (GN) 177 Beryl Amethyst, synthetic bicolored gem nodules from c with Brazil-law twinning (Koivula) Bananal mine, Minas Gerais, Calcareous concretion 159 Brazil - occurrence, origin, and 15-mm, from cherrystone clam 'Angelite," see Anhydrite description of [Kampf)25 (GTLN) 102 Anhydrite see also Aquamarine, Emerald Cameo blue-gray, sold as 'Angelite" Bolivia ceramic (GN) 110 (GN)45 amethyst-citrine from (GN) 177 plastic imitation (GN)45 Aquamarine Book reviews Chalcedony from Brazil (GN)177 Antique and Twentieth Century adularescence in (GN)244 from India (GN)177 Jewellery, 2nd ed. (Becker) 55 Chalcedony simulant from Wyoming (GN)110 Artists' Jewellery: Pre-Raphaelite glass imitation of dyed black Assembled stones to Arts and Crafts (Gere and (GTLN) 171 pearl (GTLN) 236 Munn) 253 Chatons radioactive synthetic spinel-and- Channel Setting Diamonds radioactive foil-backed rhinestones glass triplets (Nassau)232 (Wooding) 119 (Nassau) 232 Asterism Color Encyclopedia of Gemstones, Chicken-blood stone in garnet from Idaho [GN]45 2nd ed. (Arem) 55 from China (Wang) 168 in 204.39-ct blue sapphire (GTLN) Descriptions of Gem Materials, China, People's Republic of 35 3rd ed. (Vargas and Vargas) 55 chicken-blood stone from (Wang) in unusual green sapphire [GTLN) Gemstones [O'Donoghue) 1 19 168 35 The Jade Kingdom (Desautels] 55 diamond cutting in (GN)177 Atocha, Nuestra Seiiora de Jewelry on Display, 3rd ed. diamonds and other gems from emerald and gold treasures from [Coutchie) 185 [GN] 110 (Kane) 196 Jewelry d Gems: The Buying "Chinese onyx," see Augite Augite Guide (Matlins and Bonanno) 55 Chrysoberyl green, sold as "Chinese onyx" Jewelry of the 1940s and 1950s chatoyancy and asterism in single [GTLN)35 [Raulet)55 stone (GTLN) 102 Australia Mineral Museums of Europe star, from Sri Lanka (GN)244 offshore diamonds [GN)110 (Burchard and Bode) 55 Coating zircons from Harts Range The Retail Jeweller's Guide, 5th ed. on diamond (GTLN) 102 [Faulkner)207 (Blakemore) 253 Colombia

Annual Index GEMS & GEMOLOGY Winter 1989 261 emeralds from, found 011 Atocha I [Kane) 196 from China [GN] 110 Inclusions underground mining of emeralds at Dominican Republic classic, in ruby (GTLN) 102 Muzo (GN) 110 pectolite from [Woodruff) 216 cloud-like needles in diamond Color, cause of [GTLN) 102 in morganite nodules from Brazil E of coarse silk in heat-treated (Kampf]25 Emerald sapphires (EF) 42 in pectolite [Woodruff] 216 from Capoeirana, Minas Gerais, in emeralds from the Atocha in Polynesian black pearls [Goebel] Brazil - history, geology, mining, [Kane] 196 130 and gemological properties of in emeralds from Capoeirana in tourmaline from Paraiba (GN) (Epstein] 150, (GN)45 [Epstein) 159 244 from Gujar Killi, Palzistan- in filled diamonds (Koivula]68 Corundum, synthetic geology, gemology, mining, and of garnet in diamond [GTLN] 236 shaped into crystals (GN] 244 production of (Bowersox] 16 of hematite and rutile in zircon Covellite from Nuestra Senora de Atocha- from India [GTLN) 102 as a gem material (GTLN)35 discovery and gemology of limonite-stained, in topaz Cubic zirconia simulant (Kane] 196 (Kammerling) 165 foil-backed glass (GTLN)236 Opticon treatment of (GN) 177 of muscovite in beryls from plastic filling of [GTLN] 102 Bananal mine [Kampf]25 D underground mining of, at Muzo needle-like, in flame-fusion 'Demi-pearl" (GN] 110 synthetic ruby (GTLN)35 combination pearl and calcareous Emerald simulant of sets of needles in diamond concretion (GTLN] 171 made from quartz [GN)45 [GTLN]35 Diamond in spinel from USSR (GTLN] 35 with almandine-pyrope inclusion F two-phase, in emeralds from Gujar (GTLN]236 Faceting Killi (Bowersox) 16 coated, to alter color [GTLN)35, of emerald from Pakistan Insects 102 (Bowersox] 16 used in jewelry (GTLN) 171 with color-change garnet inclusion of zircon (Faulkner) 207 Irradiation [GTLN] 236 Fakes of diamonds produces color zoning with concave table [GTLN] 17 1 cubic zirconia imitations of (Fritsch]95 cube, with unusual inclusion diamond octahedra [GN)45 see also Radioactivity (GTLN) 102 imitation opalized shells [GN] 177 engraved tablet [GTLN) 171 inclusions added to quartz and J exploration in Canada and U.S. chalcedony (GN] 45 Jade simulant [GN) 177 'manufactured" emerald specimen bowenite [GN) 177 filling of fractures in, to enhance (GN)110 Jadeite clarity (Koivula]68, [GN]244 quartz imitation of emerald (GN] plastic-treated beads (GTLN] 236 irradiated (GTLN] 102, 236 45 Jewelry radium-produced radioactivity in synthetic corundum imitation gold and emeralds, from the [GTLN)236 crystals [GN]244 Atocha [Kane] 196 with sets of parallel needles Feldspar, see Orthoclase period, modern gem substitutes in (GTLN]35 (GTLN)35 in space [GN) 110 G with unusual wear [GTLN] 171 Garnet K Diamond, colored availability of hydrogrossular from Kingsley sapphire with color-zoned pavilion due to South Africa (EF) 42 162.26-ct bicolor from Australia treatment [Fritsch)95 see also Almandine, Rhodolite, [GN] 177 fancy yellow, with natural green Spessartine irradiation stain (GTLN] 102 Gemology L Hope diamond, grading of history of [Dirlam] 2 simulant (Crowningshield] 91 "Green amethyst," see Quartz dyed blue (GTLN) 102 yellow-and-colorless bicolor "Larimar," see Pectolite (GTLN] 236 H Diamond, cuts and cutting of Hackmanite M in China (GN) 177 "color change" produced by U.V Malawi in Mauritius (GN]244 radiation (GN] 110, 244 amethyst scepters from (GN) 177 Diamond, synthetic Heat treatment Mining produced by TNT detonation of amethyst to citrine [GN) 110 of emeralds at Capoeirana, Brazil (GN]45 of "rutilatedl' topaz (Kammerling) (Epstein] 159 Sumitomo produces 5-ct yellow 165 of emeralds at Gujar Killi, Pakistan (GN)45 in sapphire may leave coarse silk [Bowersox) 16 thin films (Fritsch]84 [EF) 42 of pectolite in the Dominican 2-kg piece from USSR actually Hope diamond Republic (Woodruff) 216 cubic zirconia (GN)45 grading of (Crowningshield] 91 "Mojave blue," see Chalcedony

262 Annual Index GEMS & GEMOLOGY Winter 1989 Morganite, see Beryl rock crystal, from Mexico [GN) description, care, and use of Mother-of-pearl 110 [Dirlam)2 gambling chips [GN)45 rose, from Connecticut [GN) 110 Spectra see also Amethyst and infrared, to identify plastic opal N Amethyst-citrine simulant [Koivula)30 Naini bia Quartz, synthetic infrared, in plastic-treated jadeite large quartz crystals from [GN) with Brazil-law twinning (Koivula) (GTLN)236 177 159 of pectolite from Dominican new diamond mine at Elizabeth hydrothermally grown amethyst, Republic (Woodruff)216 Bay [GN)177 citrine, and rock crystal [GN]45 reflectance infrared-application to Nigeria gem identification (Martin) 226 tourmaline from [GN)45 R Spectroscope Radioactivity digital scanning diffraction-grating 0 correction in Ashbaugh article [EF) instrument developed (GN]45 42, 109 Spessartine 'Oolongoli te" disclosure of (EF) 109 new garnet-like synthetic (GN)244 708-ct crystal (GN)45 in radium-treated diamond [GTLN) Spinel "Opal Essence," see Opal simulant 236 Opal simulant pink, from USSR (GTLN)35, in rhinestones and synthetic (GN)244 'Opalite" ("Opal Essence"), plastic spinel-and-glass triplets (Nassau) imitation with play-of-color- Spinel, synthetic 232 flux-grown from USSR [GN)244 gemology and identification of "Rainbow lattice sunstone," see (Koivula)30 and-glass triplet, radioactive Orthoclase [Nassau) 232 "Opalite," see Opal simulant Rhinestones Opticon Sri Lanka radioactive [Nassau)232 1989 update [GN)244 to treat emeralds (GN)177 Rhodolite Orthoclase Star of Abdel Aziz diamond "raspberry" from Tanzania and 59-ct D-IF named (EF)42 "rainbow lattice sunstone" from India [GN)45 Australia [GN)45 star, from Tanzania (GN)45 ' T a', Ruby P . 1, classic natural inclusions in with iridescent coating [GTLN) Pakistan [GTLN) 102 171 emeralds from Gujar Killi damaged by retipping mounting Thailand [Bowermx) 16 [GTLN)236 blue sapphires from Kanchanaburi Pearls Ruby, synthetic (GN)177 assembled [GTLN)236 flame-fusion with needle-like offshore exploration for rubies and black, from French Polynesia inclusions (GTLN)35 sapphires (GN)177 [Goebell 130 star, early flame-fusion [GTLN) Thin films chipped due to improper 171 of synthetic diamond (Fritsch) 84 [GTLN) 171 Topaz freshwater, from U.S. (GTLN)35, s heat treated to alter inclusions in (GN) 110 Sapphire (Kammerling) 165 Pearls, cultured asterism in 204.39-ct blue (GTLN) Tourmaline dyed (GTLN) 171, 236 35 from new pocket at Himalaya Polynesian black - anatomy, asterism in unusual green color mine, California (GN) 110 culturing, treatments, grading, [GTLN)35 from Nigeria (GN)45 and identification of (Goebel) from Burundi (GN)244 from Paraiba, Brazil (GN] 177, 130 classic "padparadscha" [GN) 110 [GTLN)236, (GN]244 314 blister (GTLN)35, (GN)177 40.3-kg blue crystal from Sri unusual multi-colored, from Pectolite Lanka [GN] 244 Turkey (GN)244 blue, from the Dominican heat-treated, features in (EF)42 "Transvaal jade," see Garnet, Republic-history, geology, and from Kanchanaburi, Thailand hydrogrossular gemology of (Woodruff)216 (GN) 177 Treatment Phosphophylite from Kenya [GN)1 10 coating of diamond (GTLN)35 220-gram blue-green crystal 162.26-ct bicolor from Australia of cultured pearls to simulate (GTLN)35 (GN) 177 black pearls (Goebel) 130, Psilomelane from Ottawa, Canada (GN)110 (GTLNI 236 as carving material (GN)244 unusual color zoning in, from of 'emeralds, with Opticon [GN) Australia (GN)1 10 177 Q Sapphire, synthetic glass filling of diamonds (Koivula) Quartz Czochralslzi-grown pink (GN)110 68, (GN)244 largest faceted colorless is 8,512 ct Scapolite plastic filling of emerald (GTLN) [EF)42 26.1 1-ct purple (GTLN)236 102 quench-crackled, dyed green (GN) Sinlzanlzas Library plastic filling of jadeite (GTLN) 244 purchased by GIA - history, 236

Annual Index GEMS & GEMOLOGY Winter 1989 263 see also Heat treatment, Irradiation x z Twinning X-radiography Zircon in synthetic quartz (Koivula) 159 of pearls (Goebel) 130 from Harts Range, Australia- X-ray fluorescence mining, geology, gemology, and u to identify silver treatment in faceting of (Faulkner)207 USSR pearls (Coebel) 130, (GTLN)236 pink, from Orissa, India, with pink spinel from (CTLN]35 X-ray transparency unusual inclusions (CTLN] 102 to separate calcite and w (GTLN] 102 Wollastoni te carving material from Nevada Y (GN)45 Yehuda treatment (Koivula) 68 Indexes prepared by Dona Dirlam

AUTHOR INDEX This index lists, in alphabetical order, the names of authors of all articles that appeared in the four issues of Volume 25 of Gems &> Gemology, together with the inclusive page numbers and the specific issue [in parentheses]. Full citation is provided under the first author only, with reference made from joint authors. A Fryer C.W., see Koivula J.I. Koivula J.I., see Fritsch E., Anwar J., see Bowersox G.W Kammerling R.C., and Kane R.E. G B Goebel M., Dirlam D.M.: Polynesian L Bowersox G.W., Anwar J.: The Gujar black pearls, 130-148 (Fall) Lewand E.A., see Nassau K. Killi emerald deposit, Northwest Cuo J., see Wang F. Liddicoat R.T: New challenges for Frontier Province, Pakistan, 16-24 the diamond industry, 67 (Summer] (Spring1 H Liddicoat R.T.: Congratulations!, 129 Hargett D., see Koivula J.I. (Fall) c Liddicoat R.T.: Reflections on the Conner L., see Fritsch E. K 1980s, 195 [Winter) Cook J.L., see Dirlam D.M. Kammerling R.C., Koivula J.I.: M Crowningshield R.: Grading the Thermal alteration of inclusions in McClure S.F., see Kane R.E. Hope diamond, 9 1-94 (Summer] "rutilated" topaz, 165-167 [Fall] Martin F., Merigoux H., Zecchini l?: D Kammerling R.C., see Kane R.E. and Reflectance infrared spectroscopy Koivula J.I. Dirlam D.M., Misiorowski E.B., in gemology, 226-23 1 (Winter] Kampf A.R., Francis C.A.: Beryl gem Merigoux H., see Martin F. Cook J.L., Weldon R.: The nodules from the Bananal mine, Sinkankas library, 2-15 (Spring) Misiorowski E.B., see Dirlam D.M. Minas Gerais, Brazil, 25-29 Moldes R., see Kane R.E. Dirlam D.M., see Goebel M. (Spring) Kane R.E., Kammerling R.C., Moldes N E R., Koivula J.I., McClure S.F. Smith Epstein D.S.: The Capoeirana C.2: Emerald and gold treasures of Nassau K., Lewand E.A.: Mildly emerald deposit near Nova Era, the Spanish galleon Nuestra Senora radioactive rhinestones and Minas Gerais, Brazil, 150-158 (Fall] de Atocha, 196-206 (Winter) synthetic spinel-and-glass triplets, Kane R.E., see Koivula J.I. 232-235 (Winter) F Keller AS.: The Gems ft) Gemology Faulkner M.J., Shigley J.E.: Zircon most valuable article award, 1 s from the Harts Range, Northern (Spring) Shigley J.E., see Faulkner M.J. and Koivula J.I., Kammerling R.C., Territory, Australia, 207-215 Fritsch E. Fritsch E., Fryer C.W., Hargett D., (Winter] Smith C.P., sec Kane R.E. Francis C.A., see Kampf A.R. Kane R.E.: The characteristics and Fritsch E., Conner L., Koivula J.I.: A identification of filled diamonds, preliminary gemological study of 68-83 (Summer) w synthetic diamond thin films, Koivula J.I., Fritsch E.: The growth of Wang F., Quo J.: Chicken-blood stone 84-90 [Summer) Brazil-twinned synthetic quartz from China, 168-170 (Fall) Fritsch E., Shigley J.E.: Contribution and the potential for synthetic Weldon R., see Dirlam D.M. to the identification of treated amethyst twinned on the Brazil Woodruff R.E., Fritsch E.: Blue colored diamonds: Diamonds with law, 159-164 (Fall) pectolite from the Dominican peculiar color-zoned pavilions, Koivula J.I., Kammerling R.C.: Republic, 216-225 [Winter] 95-101 (Summer) "Opalite": Plastic imitation opal Fritsch E., see Koivula J.I. and with true play-of-color, 30-34 z Woodruff R.E. (Spring] Zecchini, P., see Martin F.

264 Annual Index GEMS & GEMOLOGY Winter 1989