WINTER 1990 Volume 26 No. 4

TABLE OF CONTENTS

EDITORIAL 247 The Country of Origin Question Richard T Liddicoat

FEATURE 248 The Legendary Dresden Green Diamond ARTICLES Robert E. Kane, Shane P. McClure, and Joachim Mei~zhausen Diagnostic Features and Heat Treatment of Kashmir Sapphires Rolf Schwieger

NOTES; 282 An Investigation of a Suite of Black Diamond Jewelry AND NEW Robert C. Kammerling, Robert E. Kane, John I. Koivula, TECHNIQUES and Shone P. McClure "Emeraldolite": A New Synthetic Emerald Overgrowth on Natural Beryl Dominiifiie Robert, Emmanuel Fritsch, and John I. Koivula

REGULAR 294 Gem Trade Lab Notes FEATURES 300 Gem News 310 Gemological Abstracts 318 Book Reviews 320 Annual Index

ABOUT THE COVER: The Dresden Green is one of the few green diamonds that is known to be of natural color. At approximately 41 ct, it is also one of the largest, and, to some, the finest, natural-color green diamonds in existence. Two senior staff members of the GIA Gem Trade Laboratory traveled to Dresden, Germany, to study in depth this remarkable stone; they ware aided in this research by the director of the Green Vaults, the collection to which the Dresden Green belongs. The illustration reproduced here is based on a reconstruction suggested by Herbert Tillander. It is derived from written descriptions of the badge of the Order of the Golden Fleece, reportedly manufactured in 1746, in which both the Saxon White and Dresden Green were believed to be set. Rendering by Judy Evans, Krementz Gemstones; @ Robert E. IZane. 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.

@ 1991 Gemological Institute of America All rights reserved ISSN 0016-626X EDITORIAL Editor-in-Chief Editor Editor, Gem Trade Lab Notes

STAFF Richard Liddicoat Alice S. Keller - - T. C. W Frver,-- Associate Editors 1660 Stewart St. Santa Monica, CA 90404 Editor, Gemological Abstracts William E. Boyajian Dona M. Dirlam Peter C. Keller Telephone: (800) 421-7250 x25 1 D. Vincent Manson Subscriptions Editors, Book Reviews John Sinkankas Gail Young Elise B. Misiorowski Technical Editor Telephone: (800) 421-7250 x201 Loretta B. Loeb Carol M. Stockton Fax: (213) 828-0247 Editors, Gem News Assistant Editor Contributing Editor John I. Koivula Nancy K. Hays John I. Koivula Robert C. Kammerling

PRODUCTION Art Director Production Artist Word Processor STAFF Lisa Joko Carol Winlzler-Silver Ruth Patchick

EDITORIAL Robert Crowningshicld Robert C. Kammerling Kurt Nassau REVIEW BOARD New York, NY Santa Monica, CA P. 0. Lebanon, N1 Alan T Collins Anthony R. Kampf Ray Page London, United Kingdom Los Angeles, CA Santa Monica, CA Dennis Foltz Robert E. Kane George Rossman Santa Monica, CA Santa Monica, CA Pasadena, CA Emmanuel Fritsch John I. Koivula Kenneth Scarratt Santa Monica, CA Santa Monica, CA London, United Kingdom C. W Fryer Henry 0. A. Meyer Karl Schmetzer Santa Monica, CA West Lafayette, IN Petershausen, Germany C. S. Hurlbut, Jr. Sallie Morton James E. Shigley Cam bridge, MA San lose, CA Son t4 Monica, CA

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here was a time when the source of diamonds was considered important by some Tdealers. If it were possible to establish that a diamond came from Golconda in India, for example, it was considered to be superior. Actually, if the diamond had fine color and was highly transparent, it met the standards thought to be characteristic of the very finest product from Golconda. Over the years, impartial laboratory grading has rendered opinions on diamond source, though interesting, unnecessary.

Such a situation is not true with rubies and sapphires. It would appear that if a ruby originated in Burma, it has a mystical property that makes it worth appreciably more than an identical ruby from another source. The same situation applies to sapphires from Kashmir. Yet, if two stones are identical in appearance, with no hidden faults, it is difficult to understand why one should have greater value than the other.

In many cases, an experienced gemologist can be relatively certain that a ruby came from Burma, or from Thailand, or from Sri Lanlza. But there are other situations in which the decision is little more than an educated guess. There are stories afloat in the jewelry industry of two stones cut from the same rough being declared from Burma in one instance and from a different source in the other. There are also cases of different origins being issued on the same stone by different laboratories. In virtually all of these cases, the decision is being made based on opinion rather than established criteria. The problem that arises when such decisions are based on opinion, even when that opinion relies on extensive experience, is that they tend to reflect on the credibility of gem testing laboratories in general.

t is my personal belief that the sourcing of colored stones misleads the public and Iimposes an artificial price differential. Why should someone pay more for an inferior ruby because it came from Burma? Gemstone purchases are made for the beauty of the stone-not for some artificial differentiation imposed by the trade or a laboratory.

One of the interesting features of the historic Dresden Green diamond, which is described in detail in this issue, is that it is believed to come from the Golconda mines of India. While this information is useful in establishing the provenance of this stone, it does not affect its intrinsic value economically or scientifically. The article outlining the diagnostic features of Kashmir sapphires not only gives guidelines for determining locality of origin, but also indicates how difficult, and even precarious, efforts to determine the source of a stone can be at the present time, even for the most experienced gemologist,

There is no question that diamond sales have been improved markedly by impartial grading. I feel that sales of colored stones, likewise, could be improved materially by impartial laboratory grading of the elements of quality of such stones.

Richard T. Liddicoat Editor-in-Chief

Editorial GEMS & GEMOLOGY Winter 1990 247 THE LEGENDARY DRESDEN GREEN DIAMOND

By Robert E. Kane, Shane R McClure, and Joachim Menzhausen

The approximately 41-ct Dresden Green any gemologists dream of being able to examine diamond is the largest, and perhaps the M some of the truly famous gemstones of the world. finest, green diamond known to have a Unfortunately, few such dreams are realized, since these color of natural origin. A diamond so rich gems are rarely made available. This was the case for many in. history is well worth studying for that years with the fabled Dresden Green diamond (figure 1). reason alone> but the Dresden Grem of- Yet just such an opportunity came to pass in late unique adding fers the opportunity of November 1988, when the three authors met in the ancient valuable data to the quest for means to in distinguish natural from laboratory-inadi- city of Dresden (figure 2), what was then East Germany, ated green diamonds. In November of for the purpose of examining the Dresden Green in the 1988, two senior GIA staff members vis- Green Vaults. ited the Green Vaults with this goal in Noted jeweler and diamond historian Herbert mind. The Dresden Green diamond Tillander was instrumental in making these arrange- proved to be not only of extraordinary ments. Mr. Tillander is a grandson of the famous Alexander quality but also a vary rare type IIa-me Tillander who founded A. Tillander Jewelers,a well-known of the purest foims of diamond. In addi- firm in St. Petersburg around the turn of the century. The tion, the spectial characteristics of this Imperial family of Russia was among their clients. At a stone were found to overlap those of conference they had both attended in 1985, Mr. Tillander knmtreated diamonds. The history explained to Mr. Kane that during his research he had had locality ow,and properties of the Dim- many den Grem diamond are discussed in de- the opportunity to examine of the diamonds in the tail in this article, Green Vaults. He subsequently made the necessary intro- ductions and inquiries that enabled GLA to negotiate the first complete gemological examination of the Dresden Green diamond. The administrators of the Green Vaults gave their consent to the project in January 1986. As one might expect, the details of such a trip were many and complicated. It was ultimately agreed that the examina- tion should take place November 19-25, 1988, when the museum would be closed for cleaning and the diamond ABOUT THE AUTHORS could be removed from its display case. An invitation was Mr. Kane is supervisor of identificatfon, and Mr. subsequently extended to George Bosshait, of the Swiss MoClure is senior staff gemologist, at the GIA Foundation for the Research of Gemstones (SSEF),to Gem Tide Laboratory, lnc., Santa Monica, Cali- fornia. Dr. Menzhausen is director of the GrOnes examine the stone at the same time. Gewdbe (Green Vaults), Dresden, Germany. The importance of examining this diamond goes Phesee end of artfcle for acknowIedgments. beyond its size and history; to the need to distinguish Gems & Gemology, Vol. 26, No. 4, pp. 248-266 natural from laboratory-irradiated green diamonds, which 0 1991 Gerwiogical Institute of America is a key concern of GIA and a number of others in the

248 Dresden Green Diamond GEMS & GEMOLOGY Winter 1990

4 Pigme 1. For more than 200 years, the approx- imately 41-ct Diesdm Green diamond has resi- ded in this hat ornament made by Prague jeweler Dims bad in 1 768. The flowery bottom portion was originally fashioned by Geneva jeweler Audit Jacques Pollard in 1 746 as a section of a badge of the Older of the Golden Fleece. Photo by Shone F. MCC~UK~.

jewelry industry. One of the stumbling blocks of Streeter, 1882; Erbstein and Erbstein, 1884; Bauer, research on this subject is the fact that very few 1896; Bauer, 1904; Sponsel, 1915; Menzhausen, diamonds available for examination possess a 19681, which precludes the possibility that the green body color that can be proved to be of natural diamond might have been irradiated during its origin. The history of the Dresden Green is docu- brief tenure in the USSR after World War II. In the mented from 1741 to the present. Its recorded color authors' opinion, the consistency of these color descriptions over 250 years parallel its present descriptions with the current appearance of the appearance [Inventory Book, 1733; Gruner, 1862; stone provides overwhelming evidence that this

Dresden Green Diamond GEMS & GEMOLOGY Winter 1990 249 Figure 2. Today, the Green Vaults are part of a museum complex in the heart of Dresden. The Elbe River is in the foreground. Photo by Shane F. McClure and Robert E. Kane. diamond is naturally green. It is also the largest This article presents a brief history of the natural green diamond known. In the more than 30 Green Vaults, a detailed chronology of the legend- years of GIA Gem Trade Laboratory reports avail- ary green diamond, a discussion of the probable able, there is no record of a natural-color green locality origin of this stone, and a complete gem- diamond this large. ological description of the Dresden Green.

Figure 3. The graceful 1 vaulted ceilings compli- mented the Jewelry Room of the Green Vaults before they were damaged during World War II. Photo 0 The Wor- shipful Company of Goldsmiths, London.

250 Dresden Green Diamond GEMS & GEMOLOGY Winter 1990 A BRIEF HISTORY OF center of Dresden, two of the original three rooms THE GREEN VAULTS of the Green Vaults remained almost intact. There In 1721, Friedrich Augustus I, elector of Saxony was considerable damage, however, to the Jewel- (1694-1733) and king of Poland (1697-1733)- lery Room (figure3). In addition, the special library better known as Augustus the Strong-gave orders of the collection was destroyed by fire, including that a certain room of about 90 m2 on the some- all the card indexes and records, as well as several what elevated ground floor of the Dresden Palace files concerning the history of the Green Vaults. should have an opening made in its northern wall Hundreds of descriptive reports were also lost, to make it accessible from the adjoining hall. This together with the drawings made by the 18th- "room1'- actually three chambers- was his origi- century court jewelers. Only the inventory books nal treasury. were saved, thanks to the care and energy of Dr. The three original chambers were designated Erna von Watzdorf, one of the scholars then worlz- the "Silver Room," the "Jewellery Room," and the ing in the Historical Museum, who had them "Hall of Preciosities." Historically in this region, taken to a repository outside of Dresden. They now royal and religious treasuries alike had been closed form the basis for all new work on the Green repositories, well guarded and secured (Menz- Vaults. The collection of the Green Vaults was hausen, 1968). By opening these rooms to more returned to the German people by the Soviet general access, Augustus the Strong announced his government in 1958 (Menzhausen, 1968). The intention to have his treasury represent a new kind collection is now on display in the contemporary of collection: a museum. surroundings of the Albertinum (figure 4). The walls had originally been painted green, a fact discovered recently when portions added in HISTORY OF . the 18th~centurywere taken down for restoration. THE DRESDEN There is also reference by Augustus the Strong in GREEN DIAMOND 1727 to rooms with vaulted ceilings in this general The Dresden Green diamond has had a fascinating area that were used to house his collection. The and complex history. In researching this history, descriptive name Green Vaults (Grijnes Gewolbe) we used a variety of sources, including archives in had very probably been used colloquially by the Dresden, London, Idar-Oberstein, and the United inhabitants of the palace ever since this part of the States. The lznown chronology of the Dresden building was completed in 1554; the name appears for the first time in a document written in 1572. Today, Green Vaults is the name given to the rooms Qure 4. The collections of the Green Vaults that house the collections in what is now lznown as are now housed in a contemporary museum, the Albertinum, the museum that occupies the the Albertinum, built on the site of the original structure that used to be the Dresden Palace. The Dresden Palace. The jewellery Room is at the Green Vaults still contain artifacts and works of far end of this photo. Photo by Shane F. McClure. art from the original collection of Augustus the Strong (Menzhausen, 1968). In 1942, during the upheaval of World War 11, the collections of the Green Vaults were packed into crates and removed to nearby Konigstein Fortress, where they had been deposited twice before, during the Seven Years' War (1756-1 763) and the "Wars of Liberation" (1813).With the end of World War 11, in 1945, former French prisoners of war held at Konigstein took command of the fortress. They protected the collection until a detachment from the Soviet army that was spe- cially commissioned to safeguard works of art arrived to take it to Moscow (Menzhausen, 1968). Although most of the original Dresden Palace was destroyed during the war, along with the entire

Dresden Green Diamond GEMS & GEMOLOGY Winter 1990 251 Clironobqical Jiistory of the '~resdenQreen 'Diamond.*

During The large green diamond is brought (presumably to from Prague. The section holding the Dresden Green is or prior London) from the Golconda district of India by kept intact end is made part of the hat ornameni in to 1726 Marcus Moses. which it curen~lyresides. The section holding the ..7.?m :SftXon white also remains Intact and is made pan of a ri knot 1726 The gre~ndiamond (possibly in the rough) is offered - shoulder lhat also existi loday. for sale out of London in 1726 to ~riediich Augustus 1 ("Augustus the Strong"), elector of 1813? During the Wan of Liberation, the green Saxony and king of Poland. The asking price is diamond and the contents of the Gmen £30,00 Vaults arc again safely stored in the old Kenigstein Forrrcss. The green diamond i~sold to Friedrich A Augustus 11 at the deal Annual A 1925 Professor Rflsch and Dr. f aster Pair at Leipzig by KrUmbhaar. of Qermany, merchant named Dedea. photograph end ex.a~ninethe price has been quoted green diamond in great detail alternately as 60,000, with an optical goniometer. 200.000. w 400,000 thaler. 1942 During World War 11, the dhcniil-t collection of (be 1742 Court Jeweler Johann $Green Vault? is again Friedrich Dinglinger Is ;i~~rtd li~lie vaults of the commissioned by Friedrich Augustus I1 lo fashion a badge of 1945 AI the close

1768 After Saxony's defeat in the Seven Years War, Pallard :> 1 '988 The first complete gemological examination of the is dismantled by a jeweler named Diessbach Dresden Green diamond. w. references. -4

Green diamond is summarized in the accompany- named Delles sold it to the son of Augustus the ing box and discussed below. Strong, Friedrich Augustus 11, elector of Saxony The first reference to the presence of the green and (as Augustus 111) king of Poland (1733- diamond in Dresden is in inventory book no. 16 1763). of the Green Vaults (figure 5). The entry for the Little is known about the diamond before Dresden Green reports that in 1741 a merchant 1741. It was mentioned in a 1726 letter from Baron

252 Dresden Green Diamond GEMS & GEMOLOGY Winter 1990 SylSecond Vmwer Lit: V SixlH Sdelf Folio: 202

1 'Tffr gwrt liiaimuTivas swpfitd in 1741 - ,by tIftJwVelfesand haweiqKtsf160 - ~wM,^^TKe ~eldtn'fleece was tttude by Sfit - - Cmtf 'Jtivekr TOiiiiJingtr and dtiiiwrd in I 1742 to *en Vault. Xole . 6% goldri~fiinabsfiitf hangin below, witfi the het diamonds transferre/ to it, belong to rfie fipfrfcn Ttm tntd rfie cut's eyes as recorded. See rert(/ite dated July 3 1,1743,

V* Figure 5. The hat ornament containing the Dresden Green diamond is seen here displayed on the original inventory book no. 16 of the Green Vaults. The book is open to entry No. 50, in which the acquisition of the green diamond is recorded. A translation of this entry is given below. It is interest- ing to note that the cover of the book is green (see inset), Photos by Shane F. McClure.

Dresden Green Diamond GEMS & GEMOLOGY Winter 1990 253 Gautier, "assessor" at the "Geheimes Path's Colle- Dresden Green after the stone was in the hands of gium" in Dresden, to Le Coq, then Polish ambas- Saxon royalty the logical source of the model is the sador to London. The letter spoke of the green cutter of the diamond, sometime before 1741. diamond being offered to Augustus the Strong by a Friedrich Augustus I1 purchased the green merchant from London for the sum of 30,000 diamond at the Great Annual Easter Fair at Leipzig pounds sterling (Boutan, 1886). (Boutan, 1886). The merchant, Delles, has been The only other reference to the existence of the alternately described as Jewish (Green Vaults in- green diamond before 1941 that the authors were ventory book no. 16), Armenian (Boutan, 1886), able to locate was encountered in a book by Dutch (Copeland, 1974)) and English (Watzdorf, respected mineralogist C. J. Spencer (1971). 1962).The purchase price of the Dresden Green is Spencer makes reference to a model of the Dresden also a matter of controversy in the literature. The Green diamond that was part of the massive most frequently quoted figure is 200,000 thaler collection of Sir Hans Sloane, which was acquired (Streeter, 1882; Erbstein and Erbstein, 1884; by the British Museum of Natural History in 1753. Filhrer, 1918; Watzdorf, 1962; Holzhausen, 1966; On checking with the museum, we discovered that Menzhausen, 1968; Balfour, 19871, while other they did indeed have such a model (figure6). In fact, references list 60,000 thaler (Cattelle, 1911; Bauer, they have two. The registry index cards (registry 1932). The most interesting reference we uncov- no. 85438 A and B) for these models state that one ered quotes still another price. It is mentioned in a of them is probably from Sloane. An entry that collection of letters of Frederick the Great, king of appears to be from Sloane's own catalog of his Prussia (1712-1786), that was compiled by Max collection is quoted on the registry card: "A mo- Hein (1914).The quote states that "For the siege of dell of the green diamond brought from the dia- Brunn the King of Poland was asked for heavy mond mines in Golconda by Marcus Moses valued artillery. He refused due to the scarcity of money; at 20000 Is." This remarkable record, of which we he had just spent 400,000 thaler for a large green could find no previous report in the literature, both diamond." establishes a firm link between the green diamond In 1742, Friedrich Augustus I1 ordered Court and India, and names the man who first brought Jeweler Johann Friedrich Dinglinger to set the the rough to the West. We could find no further green diamond in a badge of the Order of the mention of Marcus Moses in the course of our Golden Fleece. This order was founded in 1429 by research. Because it is unlikely that a private Phillip the Good to encourage and reward virtue collector could have acquired a model of the and faith among men of high lineage (Tillander, 1988). The original Golden Fleece only survived four years. For reasons unknown, Dinglinger's Figure 6. This glass model of the Dresden Green badge was broken up in 1746. Friedrich Augustus I1 diamond was acquired by the British Museum then commissioned Geneva goldsmith Andre Jac- of Natural History in 1753. Courtesy of the ques Pallard (who was then living in Vienna) to British Museum; photo by Shane F. McClure. fashion another Golden Fleece featuring the Dres- den Green together with the largest diamond in the Green Vaults collection, the Saxon White (which has alternately been described as weighing 48.50 ct [Menzhausen, 19681 and 49.71 ct [Gaal, 19771). These two stones reportedly remained in this setting for more than 20 years (Menzhausen, 1968). The rendering of this piece shown in figure 7 is based on a reconstruction suggested by Tillander (1988). From 1756 to 1763, the contents of the Green Vaults were stored at the Konigstein Fortress to protect them against the ravages of the Seven Years' War. Several years after the close of this war (in which Saxony was defeated], Pallard's Fleece was also dismantled. In 1768, a jeweler named

254 Dresden Green Diamond GEMS & GEMOLOGY Winter 1990 Diessbach from Austrian Prague was commis- sioned to dismantle the badge and use two of the main sections to fashion a shoulder knot and a hat ornament, both of which exist today (Menz- hausen, 1968). The Dresden Green now resides in Diessbach's hat ornament (figure 1).The bottom portion of the ornament that contains the green diamond is actually an intact section of the Golden Fleece made by Pallard (Menzhausen, 1968). From the back (figure 81, one can still see a loop on the bottom of the piece that once connected it to the flames of the Golden Fleece. Above this section Diessbach added a ribbon-like design set with rows of small old-mine-cut diamonds that sweeps up from the sides and culminates in a bow. The bow is set with somewhat large antique-brilliant-cut dia- monds. In addition, two large antique-cut bril- liants were added, one in the center of the bow and another directly below it in the middle of the ribbons. On the back of the bow are two large loops that allowed the hat ornament to be attached by a ribbon or hat band. The green diamond remained in the Green Vaults for the next several decades, until the early 19th century, when the Wars of Liberation forced the contents of the Green Vaults to once again be moved to Konigstein Fortress. In 1925, Prof. S. Rosch (a German mineralo- gist) and Dr. W Krumbhaar (former director of the Dusseldorf Laboratory for Diamond Research) were allowed to examine the Dresden Green in great detail with an optical goniometer. This enabled them to measure exact facet angles within the limits of the bezel that still held the diamond (Rosch and Kriimbhaar, 1926; Rosch, 1957). In 1942, the treasures of the Green Vaults were once again moved to Konigstein Fortress for safe- keeping. At the close of World War 11, a Russian organization called the Soviet Trophies Commis- sion took the contents of the Green Vaults to Figure 7. This rendering of a badge of the Order Moscow; they were returned to Dresden in 1958. of the Golden Fleece reportedly manufactured The Dresden Green and its hat ornament are by Pallard in 1746 is a theoretical reconstruc- tion based on a suggestion by Tillander (1988). now on display in the Green Vaults as part of a The top section holding the approximately 49-ct jewelry set referred to as the "Brilliant Garnitur" Saxon White diamond and the center section (figure 91. holding the Dresden Green diamond still exist today in a shoulder knot and a hat ornament, THE COUNTRY OF ORIGIN respectively. The flames and fleece on the bot- DEBATE: INDIA OR BRAZIL? tom of the piece are based on written descrip- Tillander (1988) states that "without doubt the tions and existing examples of Pallard's work. rough diamond [from which the famed 41-ct Dres- Rendering by Judy Evans, Krementz Gemstones; den Green was cut] is of Indian origin even though 0 Robert E. Kane.

Dresden Green Diamond GEMS &. GEMOLOGY Winter 1990 255 in a few publications Brazil has been suggested." The latter suggestion probably results from reports in the literature of a colorless diamond from Brazil of similar shape (butlarger, 76 ct)owned by a Mr. E. Dresden (see, e.g., Reis, 1959).This stone was also referred to as the English Dresden (Streeter, 1882). Tillander's statement receives further support from the registry card to the Sloane Collection model of the diamond that was discussed above. The description that accompanied the model stated that the original stone was of Golconda (India] origin.

THE DRESDEN GREEN: 1 PHYSICAL APPEARANCE We began our examination of the Dresden Green with a thorough evaluation of its physical appear- ance and characteristics. These included the shape and cut, estimated carat weight, proportions, fin- ish, clarity, and color (see table 1). Sham and Cut. The Dresden Green diamond is a Figure 8. The back side of the Dresden Green modified pear-shaped brilliant cut. It has the - general facet shape, small table, and large culet hat ornament clearly shows, on the bottom of the piece, the loop that is a remnant of the that are commonly associated with the old-mine Golden Fleece manufactured in 1746. Photo by and old-European styles of cutting. The attractive Shone P. McClure. overall shape of this stone has been referred to as a "pendeloque" (Boutan, 1886; Balfour, 1987). Although the Dresden Green is securely set in a gold bezel with eight prongs, we used a screw micrometer in conjunction with a gemological microscope to obtain what we believe are accurate measurements of the stone: 29.75 mm long x 19.88 mm wide x 10.29 mm deep.

Carat Weight. Because the famous green diamond could not be removed from the bezel-prongmount- ing without risk of damage to the historic metal- work, we could not obtain an accurate weight with

Figure 9. Today, the hat ornament that holds the Dresden Green is displayed as part of this set of jewelry known as the "Brilliant Gar- nitur." The hat ornament had been removed for our examination at the time this photo was taken; a disturbance in the open area of velvet above the sword indicates where it was mounted. This set of jewelry also contains the ISaxon White diamond (approximately 49 ct), set in the shoulder knot on the left, and the Dresden Yellow diamond (38 ct), one of the un- mounted yellow diamonds at the bottom cen- ter. Photo by Shane E McClure.

GEMS & GEMOLOGY Winter 1990 TABLE 1. Gemological description of the Dresden Green diamond.

SHAPE AND CUT. .. MODIFIED PEAR-SHAPED BRILLIANT8 Measurements .... 29.75 x 19.88 x 10.29 MM Weight ..,.,....., 41 CARATSb . PROPORTIONS Depth...... 51.8% Table. , , , , , . . , 51% Girdle...... EXTREMELY THIN TO VERY THINc Culet...... SLIGHTLY LARGE FINISH Polish ...... VERY GOOD Symmetry ...... GOOD CLARITY...... VS, (VERY SLIGHTLY INCLUDED)* COLORe Hue ...... GREEN Tone ...... MEDIUM (5) Saturation ...... SLIGHTLY GRAYISH (1,5) Fluorescence ..... Nonef

Â¥Faceshape and size are consistent with the antique style of cutting commonly associated with old-mine and old-European cuts. "As reported by J. Menzhausen (1986). ~Afearlythe entire area 01 the girdle is covered with nicks and chips, with a very few bruted areas. *The nature and location of the inclusions and surface blemishes that could be seen (given the presence of the bezel) suggest that if this diamond were properly recut it could possibly receive an internally flawless or even a flawless grade. We are not, however, suggesting that such an important historical diamond ever be recut. 'In accordance with GIA Colored Stone Grading System nomenclature. When wpesed to a GIA Gem Instruments 4-wall combination short-wave (254.6 nm)/long-wave (366 nm) ultraviolet radiation lamp. a modern electronic balance. However, we were Proportions. As discussed above, in 1925 Rosch able to establish an estimated weight. On the basis and Kriimbhaar used an optical goniometer to of extensive archival research, we concluded that measure the angles of inclination of all the com- the last time the diamond was weighed was before pletely accessible facets outside the bezel mount- it was set in its present "bezel" mounting in 1742. ing (Rosch, 1957; see table 2).Tillander (1988)also The original 1741 handwritten entry in the no. 16 studied the cutting and proportions of this dia- inventory book of the Green Vaults (again, see mond. Table 3 shows the present authors' analyses figure 5) states that the green diamond "has a of the Dresden Green's proportions. weight of 160 green [sic]." This is in reference to The depth percentage of a pear shape is its depth the English word "grain." Based on numerous (table to culet) expressed as a percentage of its calculations made by Streeter (18821, there are four maximum width (perpendicularto its length) at the grains in an antique carat. This would equate to a girdle. This value is calculated by simply dividing weight of 40 antique carats for the Dresden Green. the actual depth by the width. The depth percentage The carat as a unit of measure was not stan- of the Dresden Green diamond is 5 1.8%. dardized until the metric carat (200 mg) was The accepted method of expressing the table accepted in the beginning of the 20th century. percentage of fancy-cut diamonds is first to measure Before then, its value depended on the city or the width at the center of the table, point to point, in country in which it was being used. In Leipzig, millimeters. This measurement for the Dresden where the Dresden was purchased, one carat was Green was 10.15 mm. This value is then divided by equal to 205 mg (Lenzen, 1970).Thus we arrive at the largest width (at the girdle), which was 19.88 the generally accepted weight of 41 metric carats mm. The table percentage for the Dresden Green for the Dresden Green (Menzhausen, 1968, 1986). diamond was calculated to be 5 1% . Prof. Rosch and Dr. Krumbhaar (1926)arrived at Because of its unique bezel-prong setting, about approximately the same weight on the basis of the 20% of the girdle was completely obscured from calculations they made during their 1925 exam- view. The areas that were visible ranged from ination of the stone. extremely thin to very thin, and were marked by

Dresden Green Diamond GEMS & GEMOLOGY Winter 1990 257 TABLE 2. Data and illustrations from Professor Rdsch and Dr. Krumbhaar's 1925 detailed examinations of the Dresden Green diamond, including precise facet angle measurements obtained using an optical goniometer (Rdsch and Krumbhaar, 1926; Rosch, 1957).

Surface Angle of Azimuth Facet namea number inclination angle

Table 1 0 - Star facets 4-5 22.3 38.2 3-6 30.8 72.0 2-7 30.1 100.9 9-8 27.5 157.0 Bezel facets 14 26.9 0.0 13-1 5 37.3 62.7 1 2-1 6 42.6 86.9 11-1 7 37.6 130.0 10 38.0 180.0 Upper girdle 25-26 40.1 33.2 facets 24-27 39.9 57.7 23-28 48.2 74.1 22-29 48.5 81.7 21-30 47.5 93.2 20-3 1 45.5 118.0 19-32 44.2 150.0 18-33 44.6 171.2

Culet 34 0 - Pavilion 39 21.4 0.0 main facets 38-40 29.6 61.3 3741 32.1 84.4 3642 26.2 123.8 35 24.3 180.0 Lower girdle Professor Rosch was unable to facet numbers obtain goniometrical measurements 43-58 on the lower girdle facets, because the airdle was obscured bv the bezel mounting. He did, however, state "that their angle is around 40 This 1925 photo taken at the Green Vaults by Rosch and degrees" (ROsch, 1957). Krumbhaar shows crown and pavilion views of the Dresden Green, along with a 17-ct drilled briolette-cut colorless aThe English translation 01 most of the facet names has been diamond and a light blue diamond set in a ring. Courtesy of converted to modern terms. the Rudolf Droschel Archive, Idar-Oberstein.

numerous nicks, abrasions, and small chips. The viewed through it could be seen very clearly. While girdle was slightly wavy. the superior polish on the stone certainly contrib- The culet, an elongated heptagon, measured 3.25 utes to this, the diamond itself has an apparent mrn x 1.65 mrn. In GLA diamond-grading terms, the transparency that is, in the experience of the authors, culet of the Dresden Green would be called slightly very rare. It is reminiscent of that observed in large. colorless diamonds from the ancient Golconda rnin- ing district of India, which are also frequently large Finish. We were very impressed with the quality of (see Krashes, 1988, for illustrations and descriptions the finish. It seemed remarlzable that a diamond cut of famous Golconda diamonds once sold by Harry prior to 1741 would have a polish of sufficient Winston). Diamonds from the Golconda district are quality to deserve a "very good" grade by today's legendary throughout the diamond trade for their rigid diamond-grading standards. The symmetry exceptional transparency, which is rarely equaled in was "good," displaying only very minor pointing and diamonds from other localities (Bauer, 1896; Bauer, alignment faults, a slightly wavy girdle, and several 1904; Gaal, 1977; R. Crowningshield, pers. con-un., extra facets on the pavilion at the girdle. 1990). Although the assessment of transparency is Clarity. One is immediately impressed by the excep- unavoidably subjective, the remarlzable transpar- tional transparency of the Dresden Green. In spite of ency of a "Golconda-type" diamond is not soon the considerable thickness of the diamond, objects forgotten.

258 Dresden Green Diamond GEMS & GEMOLOGY Winter 1990 TABLE 3. Proportions of the Dresden Green diamond,

Parameter Measurement (mm) Percentage3

Length 29.75 - Width 19.88 100 Total depth 10.29 - Depth percentage - 51.8 Tableb 10.15 51.1 Crown height Averagec 4.2 21.1 End 5.0 25.2 Tip 4.0 20.1 Center, right 3.7 18.6 Center, left 4.1 20.6 Girdle (concealed by bezel) - Pavilion depth0 6.1 30.7 Length to width ratio-1.5:l Crown angled-43O Pavilion angled-32'

'All percentages are expressed in relation to the width 01 the stone (width = 100%). Width. CEstimated averages, "Refers to average of surface angles of center bezel facets and center pavilion main facets, respectively, in relation to the girdle plane, as reported by R6sch (1957).

We determined the clarity of the green diamond to be VS, . As the plotting diagram in figure 10 shows, all of the chips and small feathers are near the girdle and all are fairly shallow. The only completely internal inclusion is a tiny opaque brown crystal (approximately0.1 mm x 0.05 mm) that is plotted under a bezel facet. We estimated the crystal to be located approximately 0.15 mm from the nearest surface of the pavilion. Even with high magnifica- tion (near 120x), we could not identify a clear crystal habit for this inclusion. It appeared to be an aggregate composed of minute, slender, pointed crystals. Over the course of two-and-a-half centuries, the Dresden Green diamond has suffered only very slight abrasion damage on some of the facet junc- Figure 10. In this plotting diagram of the Dres- den Green diamond, the prongs are shown in tions, primarily around the edge of the table. A few black; chips, a feather, and a small crystal are minute abrasions are present on other crown facet plotted in red; the scratch and the radiation junctions, as well as on the junctions in the vicinity stains are plotted in green; and the cavity is of the culet. Even the most prominent of these plotted in red and green. Artwork by Peter abrasions are not easily visible with the unaided eye. Johnston. There is also one small scratch on the table, as shown on the diagram in figure 10. Even with the viewing limitations imposed by cant weight loss. While we certainly do not suggest the bezel mounting, we feel that it would be possible that this should ever be done to such a historic to recut the Dresden Green diamond to improve its diamond, it is a measure of the superior quality of clarity, perhaps even to "flawless," without a signifi- this stone.

Dresden Green Diamond GEMS & GEMOLOGY Winter 1990 259 Color. The color of the Dresden Green diamond is its most intriguing feature and was the principal focus of this investigation. This color has been described in the literature by many fanciful terms, with "apple green" perhaps the one most commonly used (Streeter, 1882; Bauer, 1896; Webster, 1947; Smith, 1950; Twining, 1960; Balfour, 1987). Using GIA Colored Stone Grading nomenclature, we visually estimated the color of the diamond to be a medium slightly grayish green. Insofar as the mounting permitted, we determined that the current GIA Gem Trade Laboratory system would grade this historic stone as "Fancy Green." The ingenuity of the cutter of this stone be- comes apparent when one realizes that the Dresden Figure 11. The unusual trimgular pat tern of Green shows much more color face up than it graining seen in the Dresden Green indicates exhibits face down. The cutter apparently under- that it is a "three-point" diamond. Artwork by stood that different proportions are necessary to Peter lohnston. maximize the face-up color of fancy-color diamonds. He cut the green diamond with a ratio of crown height to pavilion depth that was contrary to what graining (Kane, 1982). These growth features, or was common practice at that time. London jeweler graining, appeared to be of a triangular octahedral David Jefferies, in his 1750 treatise on the methods of stratified structure. However, as discussed below, manufacturing diamonds, stated that the proper this diamond is a type Ua, and Orlov (1977)states proportions were approximately 33% for the crown that "type I1 diamonds do not show octahedral- and 66% for the pavilion. The Dresden Green, plane stratification." however, was fashioned with approximately 41% for The distinctly triangular pattern formed by the crown and 59% for the pavilion. Tillander (1988) these three directions of graining is not often seen states that during the early 1700s, cutting of this in faceted diamonds. It suggests that the Dresden quality almost certainly was done in London. Green is a "three point" diamond; that is, the table has been oriented parallel to the direction of a GEMOLOGICAL PROPERTIES possible octahedral face (for more information, see A thorough investigation was carried out on the Watermeyer, 1982). Dresden Green diamond to document as many gemological characteristics as possible and to Strain. Polarized microscopy with the stone held search for any evidence that might prove useful in table to culet revealed strong, tightly woven, distinguishing natural and laboratory-irradiated "cross-hatched" birefringence patterns that are green diamonds. Some of these observations con- sometimes referred to as "tatami," after the Japa- cur with those reported by Bosshart (1989);others nese straw mat of the same name (Orlov, 1977). reflect our research conducted during and subse- Both these "tatami" patterns and the linear strain quent to the examination. patterns that were also present appeared gray to black. Turning the stone in various directions Color Distribution. Examination of the diamond revealed strong linear and loose cross-hatch strain in darlzfield and diffused transmitted illumination of a somewhat higher order, with dull, moderately revealed no evidence of color zoning. The body saturated colors of yellow and blue. color was evenly distributed throughout the gem. Some of the areas of linear strain visible with crossed Polaroids seemed to correlate directly to Graining. When the stone was examined with the colorless graining seen in darlzfield illumina- magnification and darlzfield illumination, internal tion through the crown. planar graining was evident in three different directions (figure 11).The appearance of the color- Reaction to Ultraviolet Radiation. With a standard less, parallel striations was consistent with that GIA GEM short-wave/long-wave ultraviolet lamp often referred to by gemologists as "phantom" used in conjunction with a GIA GEM ultraviolet

260 Dresden Green Diamond GEMS & GEMOLOGY Winter 1990 viewing cabinet in ideal conditions of darkness, we unusual because the stains were coating the walls observed no fluorescence in the Dresden Green of a small, narrow cavity that reached the surface diamond to either long- or short-wave ultraviolet by means of a thin fissure (figure 13).This suggests radiation. that the diamond was exposed to a radioactive We then used a more powerful long-wave solution that was able to penetrate the cavity ultraviolet radiation unit (VEB Quarzlampen Mark- through the minute fissure. It is possible that other lzleeberg UA150.1, 220 volt, 140 watt, 365 nm). stains could have been present on the small With this extremely strong source, we observed a portion of the girdle obscured by the remaining wealz dull green fluorescence. There was no phos- bezel. phorescence. While these stains provide evidence that the Transmission Luminescence. Because some dia- Dresden Green originated from a green-skinned monds exhibit a phenomenon known to gemolo- piece of rough, they are much too small to account gists as transmission luminescence, we examined for any of the face-up color of the stone. The the Dresden Green for this characteristic. The Dresden Green diamond is a "body color" green diamond was placed, both table down and table up, diamond; that is, the color is uniform throughout. over the strong light source emanating from the Diamonds with green "skins" or scattered small opening of the nearly closed iris diaphragm green patches (radiation stains) are common. They over the transmitted light portal of the micro- are found in varying concentrations in many scope. The stone showed no transmission lumines- diamond deposits (Orlov, 1977; Vance et al., 19731. cence at all, not even the very wealz, whitish When such diamonds are cut, they generally pro- scattering of light seen in many fancy-color dia- duce near-colorless stones. monds. Faceted diamonds with a natural green body ft .f color, like the Dresden, are extremely rare. Unlike Evidence of Radiation Damage. One of the first transparent green surface coats, green body color things we looked for when examining the Dresden can be produced by only a few types of ionizing Green with the microscope was the presence of radiations. Alpha and beta particles penetrate dia- green or brown "radiation stains" (as they are mond to a very shallow depth, on the order of referred to in the gemological literature), which hundredths of a millimeter and a millimeter, indicate radiation damage to the stone. We fully respectively (Ashbaugh, 19881, which virtually expected to find some and were not disappointed. excludes them from causing the color in the Three areas displayed small dark green stains: two Dresden diamond, although they typically cause at the girdle edge on one side of the diamond and the green "skins" or radiation stains. The penetra- one on an upper girdle facet (figure 12)The last was tion of ionizing radiation forces carbon atoms out

Figure 12. At first glance, this appears to be a Figure 13. Upon closer inspection in reflected normal radiation "stain" (evidence of radiation light, it can be seen that the radiation stain is damage) on the surface of an upper girdle facet actually inside a cavity that has only a very of the, Dresden Green diamond, Photomicro- narrow opening at the surface. Photomicrograph graph by Robert E, Kane; magnified 25 X. by Robert E. Kane; magnified 25 X.

Dresden Green Diamond GEMS & GEMOLOGY Winter 1990 of their positions in the crystal lattice, leaving absorption spectrum (400 to 700 nm) of the Dres- behind what are known as vacancies. These vacan- den Green diamond using the GIA GEM Maxilab cies produce what is referred to as a GR1 color unit with a Beck prism spectroscope. Close inspec- center, which displays a sharp absorption band at tion at room temperature revealed no distinct 741 nin and absorbs light in the red portion of the absorption features; only a very weak, broad ab- spectrum, thereby contributing to the green color sorption was visible around 500 nm. in a diamond. The same process occurs with gamma rays and neutrons, but penetration depths are much greater U.V.-VIS Spectra. The U.V-visible absorption than for alpha and beta particles. As the docu- spectrum of the Dresden Green was recorded on a mented history of the Dresden Green predates the Pye Unicam SP8-100 UV/VIS spectrophotometer, nuclear industry by almost two centuries, natural- which was supplied and operated by George Boss- occurring radiation sources are responsible for the hart of the SSEF. This examination, performed at color. Nuclides and daughters (decay products) of close to liquid nitrogen temperature, revealed a uranium-238, thorium-232, and potassium-40 are well-developed GR [General Radiation) absorption the probable materials, as these produce alpha, system as well as very weak lines at 495 nm and beta, and gamma rays. Of these, gamma rays seem 594 nm, the TR12 line (470nin), R11 and RIO lines the most likely candidate, but there is another (310.8 nm and 393.5 nm, respectively) and a steep possibility. Uraninite, a concentrated uranium- absorption edge beginning at approximately 225 bearing oxide, sometimes undergoes natural spon- nm (as illustrated in Bosshart, 1989, p. 358). It is taneous nuclear fission, which releases neutrons, interesting to note that the spectrum of the Dres- so that neutrons as well as gamma rays may have den Green shares many similarities with a dark damaged the Dresden Green to give the diamond a green diamond that was identified as being arti- green body color (G.MacKenzie, pers. comm., 1990). ficially irradiated (see figure 14).The presence of a Nuclear laboratory radiation sources are much color-zoned culet identified this diamond as being more intense than natural sources, and therefore treated (Fritsch and Shigley 1989). produce in a matter of hours, or even minutes, a The steep absorption at 225 nm, the funda- coloration in diamond that may require hundreds mental absorption edge, is observable in type I1 of millions of years in nature (C.Ashbaugh, pers. diamonds, which have fewer crystal defects than comm., 1990). Nuclear reactors generate both their type I counterparts (Clark et al., 1956). The gamma rays and fast neutrons. GR series, ranging from GR1 through GR8, is Small green-to-brown radiation stains (dam- found in all diamonds that have been subjected to age) on the surface of diamonds used to be consid- radiation damage, with the GR1 at 741 nm being ered a strong indication (but not proof) of natural by far the strongest (Collins, 1982).The TR12 line color (Fryer et al., 198 1; Crowningshield, 1985, (TR standing for Type I1 Radiation) is the strongest 1986)'since such stains had not been reported to in a series of lines that are referred to as TR12 have been produced artificially (Fritsch et al., through TR17 (470.1,468.8 [TR12A],464.3,446.5, 1988; Kammerling et al., 1990; Shigley and Fritsch, 444.7,440.2, and 438.0, respectively). Davies et al. 1990). However, the possibility now exists that (1981) reported that these lines have only been near-colorless and light green or yellow diamonds found in type I1 diamonds that have been irradi- with these stains may be irradiated to induce or ated. The Rl1 (310.8 nm) and RlO (393.5 nm)lines intensify (to light, medium, or dark) a green color. are also produced by radiation damage. The Rll is In fact, Kammerling et al. (1990)examined several reported to be found only in type IIa diamonds faceted diamonds with brown radiation stains both (Davies, 1977); the RIO is also known as ND1 and before and after irradiation treatment. Even can be created in all types of diamonds. It is not though the originally pale green and near-colorless usually visible in type la diamonds because it is stones turned dark green with irradiation, there masked by a secondary absorption edge typical of was no change in the appearance of the radiation that type (Walker, 1979). stains. For many years, the presence of a 594-nm line was believed to prove laboratory irradiation in a Spectra Visible with a Hand-held Type of Spectro- faceted diamond (see, e.g., Liddicoat, 1989). The scope. We initially examined the visible-light line is associated with the annealing of irradiated

262 Dresden Green Diamond GEMS & GEMOLOGY Winter 1990 diamonds (Dugdale, 1953; Crowningshield, 1957; Infrared Spectra. To determine which of the well- Collins, 1982; Guo et al., 1986; Fritsch et al., 1988), recognized diamond types the Dresden Green so it is normally visible in annealed colors (e.g., belongs to, infrared spectroscopy was used. For a yellow, brown, orange, pink). It is also occasionally discussion and excellent review of these types (la, seen in laboratory-treated diamonds that are still Ib, IIa, IIb, or a mixture) see, for example, Robert- green (Kane, 1988; Fritsch et al., 1988). While the son et al. (19341, Custers (1952), Davies (19771, 594-nm line has been reported in a number of Clark et al. (19791, Collins (1982))Davies (1984)) uncut natural-color diamonds (Cottrantand Calas, and Shigley et al. (1986).Very simply stated, type I 1981; Guo et al., 1986; Shigley and Fritsch, 1990)) diamonds have a fairly substantial (up to 3000 it has rarely been reported in faceted diamonds ppm, or 0.3%) nitrogen content (Shigley et al., that could be proved to be natural. By virtue of its 1986). Type la diamonds have aggregated nitrogen documented 250-year history, the Dresden Green atoms, while the nitrogen atoms in type Ib dia- now stands as an undisputable example of such a monds are isolated or "singly sub~titutional.~~Type diamond. I1 diamonds have an extremely low nitrogen con- tent, if any (undetectable or barely detectable using IR spectroscopy]; type IIb diamonds contain boron, while type IIa stones do not contain boron in Figure 14. This visible absorption spectrum of a detectable quantities. A diamond can be readily type II green diamond that was identified as being treated by means of characteristic color characterized as to type by the way it absorbs or zoning, at the culet, shows many features that transmits infrared radiation between about 900 are present in the spectrum of the Dresden and 1400 wavenumbers (cm-1; see figure 15). Green. Courtesy of the GIA Research Depart- The infrared spectrum of the Dresden Green ment. *Â .' diamond (figure 16)was recorded at room tempera- ture on a Carl ZeissIJena Specord 75IR infrared spectrophotometer by Dr. K. Herzog and Mrs. R. Lunlzwitz of the Technical University of Dresden. The green diamond was mounted in the sample chamber with the infrared beam perpendicular to the table, so that it entered at the table and exited at the culet. The large culet and the depth (10.29 mm)of the green diamond allowed for easy set-up and an excellent optical path. As shown in figure 15, the spectrum is typical of a type IIa diamond, that is, largely free of nitrogen features in the 1400 to 900 wavenumber region. Type IIa diamonds (of any clarity and color, or absence thereof) are very rare in nature (Field, 1979). Natural diamonds that are of type IIa and have a dominant green color, whether irradiated naturally or in a laboratory, are exceedingly rare. In an ongoing GIA Research project that formally began in 1986, more than 1300 colored diamonds (which were either submitted to the GIA Gem Trade Laboratory for official reports or loaned to GIA for scientific study)have been carefully docu- mented to date. Of these, approximately 300 were predominantly green (some with secondary hues of gray, brown, yellow, blue, etc.), with varying tones and saturation (J. Shigley, pers. comm., 1990). Of these 300 "green" diamonds, only 18 were 400 500 600 700 classified as type IIa, with the remainder being WAVELENGTH (nm) type la, none was in the Ib or IIb categories.

Dresden Green Diamond GEMS &. GEMOLOGY Winter 1990 263 I I I I . 4000 3000 2000 1000 WAVENUMBER (cm-1)

Figure 16. The infrared spectrum of the Dresden Green diamond. Note the similarity of the area between 900 and 1400 wavenumbers with that illustrated in figure 15 for type IIa diamonds. This spectrum was originally recorded in trans- mittance; here, ii is shown converted to absorb- ance. Spectrum recorded by Dr. I<. Herzog and Mrs. R, Lunkwitz of the Technical University of Dresden.

green when they are cut. The cause of the green surface coloration has been attributed to the dia- mond being in close proximity to an alpha-parti- 4900 4400 3900 3400 2900 2400 1900 1400 900 400 cle-emitting source for a very long period of time. WAVENUMBER (cm-l) Laboratory-irradiated green diamonds have be- come increasingly common in the trade. Green Figure 15. These infrared absorption spectra color in diamonds has been produced by radium were recorded with the GIA Research Depart- salts since 1904, by cyclotron treatment since ment's Nicolet 60XS PTIR spectrometer for each 1942, and more recently by high-energy electrons, of the four basic types of diamond. Each type neutrons, and (less commonly) by gamma rays. can be readily characterized by the way it ab- Whereas radium and americium salts and cyclo- sorbs or transmits radiation between about 900 tron treatment leave readily identifiable clues and 1400 wavenumbers (cm- 1). (radioactivity and what is commonly referred to as the "umbrella" effect, respectively; see Kammer- ling et al., 1990), treatment by the more modern Therefore, not only is the famed Dresden Green methods is extremely difficult to detect in most the largest known natural green diamond, but it is green diamonds. also a very rare type IIa. This was an unexpected Alan Collins stated in 1982 that it would be of discovery, since type la diamonds represent as considerable help to the understanding of natu- much as 95% of natural gem diamonds (Collins, rally occurring color centers if absorption spectra 1982). could be obtained for a natural body-color green diamond. This unique opportunity to examine the CONCLUSION Dresden Green provided such information. The Natural green body-color diamonds are extremely documentation of this famous diamond is now rare in nature, and there are few documented complete, with the exception of the precise weight, examples. The Dresden Green falls into this cate- which may never be known. Our investigation gory. The vast majority of natural-color green uncovered evidence to support the opinion that the diamonds are only green on the surface of the stone was mined in India and cut in London. It was rough, with the color produced by surface stains also shown to be a rare type IIa diamond. Most and coatings. These stones are usually no longer important, perhaps, is the fact that the spectral

264 Dresden Green Diamond GEMS & GEMOLOGY Winter 1990 characteristics of this stone overlap those of for black-and-white reproductions; Herbert Tillander known treated green diamonds, which indicates for supplying historical information and making the that we must continue the search for reliable tests necessary introductions to gain access to the Green to separate natural from treated green diamonds. It Vaults; George Bosshart of the SSEF for supplying the is ironic that a stone with a history that spans more informalion on the UV-VIS spectra; Dr. Werner Quell- than two and a half centuries should play such a malz, Dr. Mathe, Mrs. Christine Engemann-Wendi, Dr. U. Arnold, Dr. Klaus Herzog, Mrs. Renate Lunkwitz, pivotal role in confirming the need for this re- Prof Dr. Walther E. Steger, Dr. Copal, Dr. Tallheim, Dr. search. Schneider, Mr. Wunsche, and all the other people in Dresden who assisted during the visit; Dr. Karl Schmet- zer, Eric Bruton, Michael O'Donoghue, Ion Balfour, Rudolf Droschel, and Mr. and Mrs. Jerusalem for their Acknowledgments: The authors lhank Dona Djrlam, help with literary research; Dr. George Rossman, Chuck Rosemary Tozer, and the others at the Richard T Ashba~igl~,Dr. Tefj Harris, Bob Crownjngshield, and Dr. Liddicoat Library and Information Center of GIA for James Shigley for their useful comments and observa- their help in archival research; Holly Baxter, Dr. Barbara tions; the GIA Research Department for making avail- Bopp, Dr. John Hummel, and Caio Maia for translations; able [heirdiamond literature database; GIA executives Dick Agnew and Bob Van den Heuvel for the design and William E. Boyajian, Richard T. Liddicoat, Courtney A. construction of specialized equipment for the investiga- Walker, Thomas C. Yonelunas, and C. W Fryer for their tion; Dr. Peter Tandy and Dr. A. M. Clark of the British support of the Dresden Expedition; and Mary Smith for Museum of Natural History, for information and loan of her expertise and patience in word processing the many the model; David Beasley of Goldsmith's Hall, London, drafts of the manuscript.

* c REFERENCES Ashbaugh C.E. (1988) Gemstone irradiation and radioactivity. Crowningshield G.R. (19861Gem trade labnotes: Natural-color Gems a) Gemology, Vol. 24, No. 4, pp. 196-213. light green diamonds. Gems &l Gemology Vol. 22, No. 3, Balfour I. (1987)Fanlous Diamonds. William Collins Sons &. on. 171-172, Co., London, pp. 74-76. ~ust&sR.M. (1952) Unusual phosphorescence of a diamond. Bauer M. (18961 Edelsteinkunde. Chr. Herm. Tauchnitz, Pllysica, Vol. 18, No. 8-9, pp. 489-496. Leipzig. Davies G. (1977)The optical properties of diamond. Chemistry Bauer M. (1904)Precious Stones. Charles Griffin and Company, and Physics of Carbon, Vol. 13, Marcel Dekker, New York. London. Davies G. (1984)Diamond. Adam Hilger, Bristol, England. Bailer M. (1932) Edelsteinkunde. K. Schlossmacher, Ed. B. Davies G., Foy C., O'Donnell K. (1981) The TR12 vibronic band Tauchnitz, Leipzig, in diamond. Journal of Physics C: Solid State Physics, Vol. Bosshart G. (1989)The Dresden Green. Journal of Gemmology, 14, pp. 41534165. Vol. 21, No. 6, pp. 351-362. Dugdale R.A. 11953)The colouring of diamonds by neutron and Boutan M.E. (1886)Le Diamant. lmprimerie A. Lauhure, Paris. electron bombardment. British Journal of Applied Bruton E. (1978)Diamonds, 2nd ed. Chilton Book Co., Radnor, Physics, Vol. 4, pp. 334-337. PA. Erbstein J., Erbstein A, (1884) Das Konigliche Criine Cewolbe Cattelle W.R. (1911) The Diamond. John Lane, The Bodley Zu Dresden. Officin von Wilheln~Baensch, Dresden. Head, London. Field J.E. (1979)The Properties of Diamond. Academic Press, Clark C.D., Ditchburn R.W., Dyer N.B. (1956)The absorption London. spectra of natural and irradiated diamonds. Proceedings of Fritsch E., Shigley J., Stockton C., Koivula J. (1988)Detection of the Royal Society, Vol. 234, pp. 363-38 1. treatment in two unusual green diamonds. Gems a) Clark C.D., Mitchell E.W.J., Parsons B.J. (1979)Colour centres Gemology, Vol. 24, No. 3, pp. 165-168. and optical properties. In J. E. Field, Ed., The Properties of Fritsch E,, Shigley J.E. (1989)Contribution to the identification Diamond, Academic Press, New York, pp. 23-77. of treated colored diamonds: Diamonds with peculiar Collins A.T. (1982) Colour centres in diamond. Journal of color-zoned pavilions. Gems a1 Gemology, Vol. 25, No. 2, Gemmology, Vol. 18, No. 1, pp. 37-75. pp. 95-101. Copeland L.L. (1974) Diamonds . . . Famous, Notable and Fryer C.W, Crowningshield G.R., Hurwit K.N., Kane R.E. Unique, 1st ed., 2nd rev. printing. Gemological Institute of (1981) Gem trade lab notes: Green diamonds. Gems a) America, Santa Monica, CA. Gemology, Vol. 17, No. 4, p. 227. Cottrant J,, Calas G. (1981)Etude de la coloration de Quelques Fiihrer diirch die Koniglichen Sa~nmlungenZLI Dresden (1918). Diamants du Museum National dlHistoire Naturelle. Albanussche Buchdruckerei, Dresden. Revue de Gemmologie a.f.g., Vol. 67, pp. 2-5. Gaal R.A.l? (1977)The Diamond Dictionary, 2nd ed. Gemologi- Crowningshield G.R. (1957) Spectroscopic recognition of yel- cal Institute of America, Santa Monica, CA. low bombarded diamonds. Gems el Gemology, Vol. 9, No. Gruner L. (1862)The Green Vaults, Dresden. C. C. Meinhold 4, pp. 99-1 17. and Sons, Dresden. Crowningshield G.R. (1985) Gem trade lab notes: Diamond Guo J., Chen F., Cai X., Deng H. (1990)Spectroscopic study of with natural internal irradiation stain. Gems &> Gemol- natural diamonds in China. Chinese Journal of Ceo- ogy, Vol. 21, No. 4, p. 233. chemistry, Vol. 9, No. 2, pp. 161-168.

Dresden Green Diamond GEMS & GEMOLOGY Winter 1990 265 Harris J.W, Hawthorne J.B., Oosterveld M.M. (1979) Regional Philosophical Transactions, Royal Society of London, Vol. and local variations in the characteristics of diamonds A232, pp. 463-535. from southern African kimberlites. In F. R. Boyd and Rosch S.. Kriimbhaar W. 119261 Die Diamanten des Grunes H. 0. A. Meyer, Eds., Diatremes and Diamonds: Their ~evklbein Dresden. ~e~iischeColdschmiede-Zeilung, Geology, Petrology and Geochemistry. Washington, DC. No. 11, pp. 114-124. Hein M. (1914)Briefe Friedrichs des Grossen. Hobbing, Berlin. Rosch S. (1957) Das Grunes Gewolbe in Dresden. Zeitschrift Holzhausen W (1966) Prachtgefasse, Ceschn~eicle, Kabinet- der Deutschen Gesellschaft fur Edelsteinkunde, pp. tstiicke, Goldschmiedekunst in Dresden. Tubingen, 1966. 79-84. Inventory Book of the Griines Gewolbe (Green Vaults) No. 16 Shigley J.E., Fritsch E. (1990) Optical properties of some (1733). Griines Gewolbe, Dresden. greenish blue to green diamonds. Diamond Optics 111 Jeffries D. (17501A Treatise on Diamonds and Pearls. C. and J. Conference Proceedings, Vol. 1325, pp. 3 15324. Ackers, London. Shigley J.E.,Fritsch E., Stockton C.M., Koivula J.I., Fryer C.W, Kammerling R., Koivula J., Kane R. 11990) Gemstone enhance- Kane R.E. (1986) The gemological properties of the Su- ment and its detection in the 1980s. Gems a) Gemology, mitomo gem-quality synthetic yellow diamonds. Gems a) Vol. 26, No. 1, pp. 3249. Gemology, Vol. 22, No. 4, pp. 192-208. Kane R.E. (1988)Gem trade lab notes: Treated green diamonds. Smith G.F.H. (1950) Gemstones, 11th ed. Methuen & Co., Gems a) Gemology, Vol. 24, No. 3, pp. 170-1 7 1. London. Kane R.E. (1982) Graining in diamond. In D. M. Eash, Ed., Spencer C.J. (1971)A Key to Precious Stones, 3rd ed. Emerson International Gemological Symposium Proceedings Books, New York. 1982, Gemological Institute of America, Santa Monica, Sponsel J.L. (1915)Fuhrer durch das Koniglichen Grimes Ge- CA, pp. 219-235, whlbe 211 Dresden. Buchdruckerei der Wilhelm und Bertha Krashes L. (1988)Harry Winston, The Ultimate Jeweler. Harry V Baensch Stiftung, Dresden. Winston, New York, and the Gemological Institute of Streeter E.W. (1882)The Great Diamonds of the World. George America, Santa Monica, CA. Bell and Sons, London. Lenzen G. (1970) The History of Diamond Production and the Tillander H. (1988) Golden fleece diamonds. Unpublished Diamond Trade. Praeger Publishers, New York. manuscript. Liddicoat R.T (1989) Handbook of Gem Identification, 12th Twining L. (1960)A History of the Crown Jewels of Europe. B. T ed., 2nd rev. printing. Gemological Institute of America, Batsford, London. Santa Monica, CA. Vance E.R., Harris J.W., Milledge H.J. (1973) Possible origins of Menzhausen J. (1968) The Green Vaults. Edition Leipzig, Leip- alpha-damage in diamonds from lzimberlite and alluvial sig, Germany. Sources. Mineralogical Magazine, Vol. 39, pp. 349-360. Menzhausen J. (1986) The Green Vaults: An Introduction, 5th Walker J. (1979)Optical absorption and luminescence in dia- ed. Staatliche IAfrica. Sons, New York. Von Watzdorf E. (1962)lohann Melchior Dinglinger, Der Gold- Raal F.A. (1969)A study of some gold mine diamonds. American scl~mieddes Deutschen Barock. Gebr. Mann Verlag, Mineralogist, Vol. 54, No. 1-2, pp. 292-296. Berlin, Reis E. (1959) 0s Grandes Diamantes Brasileiros. Divisao de Webster R. (1947) The Gemmologists' Compendium, 2nd ed. Geologia e Mineralogia, Rio de Janeiro. N.A.G. Press, London. Robertson R., Fox J.J.,Martin A.E. (1934)Two types of diamond, DIAGNOSTIC FEATURES AND HEAT TREATMENT OF KASHMIR SAPPHIRES By Rolf Schwieger

The locality origin of natural-color blue mong fine blue sapphires, it is generally recognized sapphires from l

Kashmir Sapphires GEMS & GEMOLOGY Winter 1990 267 Figure 1. Fine Kashmir sapphires are among the most sought-after of gemstones. Yet deter- mination of the locality of origin of any gemstone is difficult, and of Kash- mir sapphires is partic- ularly complex. On the basis of a variety of fac- tors. which are the focus of this article, the author and others determined that the large stone in this magnificent sapphire and diamond bracelet by Cartier is from the fa- mous Kashmir mines. At 65 ct, it is one of the largest l

HISTORY height of 4,500 m (14,800 ft.), near the level of A landslide that took place around 1881 in a small perpetual snow. In the first years of exploitation, glacial cirque above the village of Sumjam, on the some superb sapphires were found there, as well as southwest slopes of the Zanslzar range in the in placer deposits on the valley floor. In 1904, Bauer Himalaya Mountains, exposed gem-quality blue (p. 289)reported that "some [of the rough sapphires corundum crystals embedded in altered peg- from Kashmir] are of considerable size, weighing matite~[Atkinson and Kothavala, 1983). In 1884, 100 or even 300 carats." More recent finds, how- in his book Precious Stones and Gems, Edwin W. ever, have been less spectacular; today, most of the Streeter became one of the first to mention the stones on the market are small, and only rarely Kashmir mines. He tells the story of how the does one see faceted gem-quality stones over 20 ct maharajah of Kashmir heard of the discovery and (figure 3). By 1926, new mines had been opened took immediate possession of the site by sending within 200 m of the original deposit. However, his own guards to the original mine, situated at a mining operations have always been extremely

268 Kashmir Sapphires GEMS & GEMOLOGY Winter 1990 Figure 2. This Van Cleef o) Arpels necklace of predominantly Kashmir sapphires (ranging from 10.96 to 36.00 ctj and diamonds was auctioned in 1989 by Sotheby's in New York for US$3.520,000. Photo by Michael Oldford; courtesy of Sotheby's. difficult and limited by the weather to no more mining conditions, the low yield of gem-quality than three months per year. Mining has long been material, and, recently, the political upheaval in complicated, too, by political instability in the the area, no mining has occurred within the last 10 area. Two wars have already been fought between years. A new mining operation was planned for the India and Pakistan for control of the Kashmir summer of 1990, but it was not undertaken be- region since the discovery of sapphires there and, cause of the political situation. as this article is being written, the area is yet again in dispute. REVIEW OF Further information, and a detailed chronology DIAGNOSTIC FEATURES of the Kashmir deposits, can be found in Atkinson Since blue sapphire shows little variability from and Kothavala (1983).Due largely to the difficult locality to locality in its essential physical and

Kashmir Sapphires GEMS & GEMOLOGY Winter 1990 269 optical properties, most of the basic characteris- Koivula, 1986; Hanni, 1990))but these inclusions tics of Kashmir sapphires are also found in sap- have not yet been positively identified because phires from other regions. As a result, researchers they are so small. have been forced to look for subtle distinguishing Also contributing to the Tyndall effect of light features for locality determination, a search that scattering throughout these stones are clouds, has been complicated by the shortage of Kashmir lines, and strings of slightly larger but still very sapphires of reliably documented provenance - a fine, dust-like inclusions, probably exsolutions of shortage due partly to the relatively brief history of rutile (Gubelin and Koivula, 1986; Hanni, 1990)) their mining (only slightly over 100 years) and but positive identification of these inclusions, too, partly to the lack of reliable witnesses who can remains to be made. However, the cumulative attest to the origin of any particular stone. Nev- Tyndall scattering effect produced by these fea- ertheless, some research work is available for tures can be considered as indicative of Kashmir assessment. origin (Gubelin and Koivula, 1986, p. 342). "Flags" Perhaps the most obvious features of the gem- or healed fissures are commonly mentioned in quality Kashmir sapphires are their intense blue connection with Kashmir sapphires (Phulzan, color and their turbid, or "velvety," appearance 1966; Schubnel, 1972; Gubelin and Koivula, 1986; (Streeter, 1884; Smith, 1912; Bauer, 1932; Halford- Hanni, 1990),while twin lamellae have been seen, Watlzins, 1935); unlike sapphires from most other if rarely (Hanni, 1990). localities, the blue color of Kashmir sapphires Solid inclusions that have been reported in tends to improve under incandescent light. These Kashmir sapphires include zircon (euhedral, with features undoubtedly led to the rapid rise of or without fracture halos, and sometimes de- sapphires from Kashmir to their legendary status. scribed as "corroded"), tourmaline (rarely eu- However, the variable presence of these charac- hedral), and pargasite (prismatic or as long, fine teristics in Kashmir sapphires, as well as their needles) crystals (Phulzan, 1966; Schubnel, 1972; appearance - though rarely - in sapphires from Gubelin and Koivula, 1986; Hanni, 1990). Zircon other localities, makes them less than reliable as has also been observed in blue sapphires from determinants of locality. other localities, including Australia, Burma, Mon- Most of the studies 011 diagnostic features of tana, Sri Lanka, Pailin (Cambodia),and Tanzania Kashmir sapphires have focused on microscopic (Schubnel, 1972; Gubelin, 1973; Gubelin and Koi- characteristics (Gubelin, 1948, 1953; Phulzan, vula, 1986).However, tourmaline and pargasite are 1966; Schubnel, 1972; Gubelin, 1973, 1985; Gu- considered diagnostic of Kashmir origin, and have belin and Koivula, 1986; Hanni, 1990).Perhaps the not been seen in blue sapphires from other lo- most obvious microscopic feature is a sharp, well- calities (Schubnel, 1972; Gubelin, 1973; Gubelin defined color zonation that occurs in virtually all and Koivula, 1986; Hanni, 1990). Kashmir sapphires (Phukan, 1966; Atkinson and Strongly corroded colorless crystals have been Kothavala, 1983; Gubelin, 1985; Gubelin and identified as plagioclase, and in one case a colorless Koivula, 1986; Hanni, 1990). In fact, as early as crystal with stress fissures was determined to be 1904, Bauer noted that even within low-quality allanite (Hanni, 1990). The allanite crystal was and milky gray material, some of the "single identified using energy-dispersive analysis on an crystals often show a difference of color in differ- SEMI and this type of analysis also led Hanni to ent portions; thus the center of a crystal may be of identify cubic black crystals as uraninite. How- fine blue color, and the two ends colorless." Usu- ever, plagioclase has been observed in sapphires ally, the zonation consists of alternating blue and from Pailin and Thailand, and uraninite has been near-white, or "mill~y'~layers that contribute to seen in sapphires from Sri Lanka (Gubelin and the reduced transparency ("velvetinessJJ)of the Koivula, 19861, so their presence cannot be consid- stones. Although color zonation has been observed ered diagnostic of Kashmir origin. On the other in sapphires from other localities (e.g., Pailin and hand, it appears that allanite, like tourmaline and Sri Lanka), the zoning seen in sapphires from pargasite, has as yet been seen only in sapphires Kashmir is usually distinctive. The milky layers from Kashmir and can thus be regarded, when are thought to contain microscopic and sub- present, as proof of locality. Unfortunately, these microscopic particles that may be exsolutions of crystalline inclusions only rarely occur in Kashmir rutile (see Halford-Watlzins, 1935; Gubelin and sapphires.

270 Kashmir Sapphires GEMS & GEMOLOGY Winter 1990 Figure 3. Most of the Kashmir sapphires seen in the gem market today are fairly small, but a few larger stones can still be found. The unusually fine stones in this collection range from 3 to over 30 ct. Photo by Michael Oldford.

Trace-element analysis by nondestructive en- MATERIALS AND METHODS ergy-dispersive X-ray fluorescence (EDXRF)spec- Over a 10-year period, the author has had the trometry (Stern and Hanni, 1982) has also been opportunity to examine more than 500 gem- explored by Karl Vogler with considerable success quality sapphires reportedly from Kashmir (i.e., as a method that contributes to identifying the with at least one certificate of origin from a major provenance of sapphires. Graphs that relate the gem laboratory", from which a file of over 3,000 ratios Fe:Cr and Ti:Ga appear to provide the best photomicrographs was developed. In addition, dur- solution (K. Vogler, pers. comm., 1990). His re- ing a visit to Kashmir in September 1989, the search indicates that sapphires from Kashmir can author obtained six non-gem-quality Kashmir sap- be distinguished by EDXRF from those of Pailin phire crystals (figure 4) from the old stock of (Cambodia),Thailand, Australia, and Nigeria and, Jammu & Kashmir Minerals (the state-owned in some cases, from those of Burma (now Myan- company that controls the Kashmir mines]. Simi- mar). Sri Lankan sapphires are more difficult to lar non-gem-quality Kashmir sapphire rough from separate, as they have iron and chromium contents old stocks of other Indian dealers was also exam- similar to those of Kashmirs, although gallium can ined for this study. occasionally be a useful indicator. However, fur- Photomicrography was performed with a Leitz ther research is needed before conclusions can be Orthoplan mineralogic microscope, using oblique drawn about the reliability of this method for these illumination as provided by a powerful (200-watt) important distinctions. Schott fiber-optic light. Optical spectra were ob- Optical spectrophotometry has been used pri- marily to study the causes of color in blue sap- phires (Schmetzer and Bank, 1981), but, as with rubies (Bosshart, 1982; Schmetzer, 19851, it has 'Editor's Note: Although GIA recognizes the value of also been suggested that this method can provide studies to determine locality of origin of a gem material, the GIA Gem Trade Laboratory, Inc., has a long-standing means to determine the locality origin for Kashmir policy of not indicating locality of origin on any ideiitiflca- sapphires (Hanni, 1990). tion report it issues.

Kashmir Sapphires GEMS & GEMOLOGY Winter 1990 271 tained with a Beclzman DU-70 spectrophotometer and a microbeam condenser. Where possible, chemical analyses of inclusions were performed on a scanning electron microscope with an energy- dispersive system (Philips SEM 515 with a Tracer EDS). Heat treatment was performed in Bangkok 1 nn a 29-ct faceted commercial-quality specimen.

OBSERVATIONS Microscopic Features. The characteristic sharp- bordered blue (sometimes with colorless layers) and whitish (millzy)color zoning of Kashmir sap- phires was readily apparent in most of the speci- mens examined for this study (figure 5). This zoning was present in almost all of the stones, but in some cases it was difficult to see. In some of the stones, even at relatively low (40x ) magnification,

Figure 4. These six non-gem-quality samples, two of which were obtained by the author in Kashmir from the old stock of fammu a) Kash- mir Minerals, were among the faceted and rough samples examined for this study. They range from 2 to 6 ct. Photo by Michael Oldford.

Figure 5. Most of the specimens examined showed the sharp blue and milky or whitish zoning that appears to be characteristic of sap- phires from Kashmir. Photomicrograph 0 Rolf Schwieger; magnified 25 x . , LFigure 6. Even at 40x magnification, with the strong illumination provided by a powerful fiber-optic light source, the tiny particles that contribute to the haziness of the milky layers can be seen in some Kashmir sapphires. Photo- micrograph 0 Rolf Schwieger.

1 extremely fine features could be seen in the milky layers (figure 61. Using a strong fiber-optic light source in con- junction with magnification, the author also ob- served the clouds and lines of somewhat larger but still very fine, dust-like inclusions (figure 7) that are commonly present in Kashmir sapphires and also contribute to the "velvety" appearance of reduced transparency. These inclusions often re- semble snowflakes (figure 8).Sometimes they take the form of fine, short needles (figure 9).As stated

272 Kashmir Sapphires GEMS & GEMOLOGY Winter 1990 Figure 7. Clouds and lines of fine, ~USL-likein- clusions (exsolutions of rutile!) were commonly present throughout the Kashmir sopphires ex- Figure 9. 111 some insta~Ices,the dust-like parti- amined. Photomicrograph 0 Rolf Schm'eger; cles appear to be Pne, short needles. They inter- magnified 40 x . sect at 6P angles and are aligned with the hex- agonal symmetry of the sopphire. This oriento- tion suggests that they are probably exsolutioi~s of r~~tile,Pho~oinicrograph (0 Rolf Schwieger; magnified 25 x .

temperature did not allow complete formation of typical rutile needles) such as those commonly found in Sri Lankan and Burmese sapphires (figure 10; K, Vogler) pers. comm.) 1990; H. Hai~ni)pers. comin.l 1990).

Figc~re10. The appearaiIce of the dust-like in- clusions observed in l

earlier, the exact nature of these inclusions (like those in the milky layers) has not yet been deter- mined. However) their orientation - intersecting at 6W angles and aligned with the hexagonal symme-

trv- - of- - the.. - - host-- - - - corundum- - - - - [a~ain.see fi~ure91- , 3" , - 1 strongly suggests that they are exsolutions of rutile. The llsnowflalzellformations have not been seen in sapphire from other localities. The form and distribution of these articles

Kash~nirSapphires GEMS i3 GEMOLOGY Winter 1990 273 Although crystal inclusions in Kashmir sap- those shown in figure 12. Although they could not phires appear to be rare when normal magnifica- be conclusively identified by the methods avail- tion is used) high magnification (50x or more) able) their morphology suggests that they are also revealed mineral inclusions in about 60Y0-70Y0 of pargasite. In the author's experience) this type of the specimens examined. ln as many as half of inclusion has not been seen in sapphires from these instances! magnification of 100~or more other localities. was required to determine the morphology of the Tourmaline as an associated mineral of Kash- incl~~sions.Positive mineralogic identificatioil of mir sapphires has been described by several re- such inclusions usually depends on their exposure searchers (e.g.) Bauer! 1904; Smith) 1912; Halford- at the polished surface of a cut gem. However, since Watlzinsl 1935; Brown! 1956; Atlzinson and Ko- these stones are too valuable to be sacrificed to thavala) 1983; Gubelin and Koivula! 1986; Hanni) scientific ii~vestigatioi~~this could not be done in most instances. Further research using a Raman laserprobe) which allows analysis of subsurface inclusions (Fritsch and Rossman) 1990))is needed. Schubnel(l977)was the first to identify (by SEM- EDS) pargasite as an inclusion in Kashmir sap- phire) and his findings have since been coilfirmed by Hanni (1990) and this study [also using SEM- EDS). These needle-lilze inclusions (figure 11) sometimes cut across an entire stone) and were seen in abo~~t10Y0 of the specimens. About 5Y0 of the study stones were found to contain longl prismatic) colorless crystals such as

Figure 11. Long, thin, needle-lilze crystals of Figure 12. This type of long, prismatic, colorless pargasiie were observed in about 10% of the crystal was also observed in a number of tl~e stones examined for this study Pargosite 110s sample Kashn~irsapphires, W11ile these crystals not been reported in sapphires from otller 10- could not be identified with available methods, calities. Photomicrogrnph 0 Rolf Schwieger; their morphology suggests that thex too, are magnified 40~. porgnsite. Photomicrogrnph 0 Rolf Schwieger; magnified 100 x .

Figure 13. Although tourmaline commonly oc- curs in association with sapphires from IZas11- mir, it was only rorely observed (1s an incl~~sion in the sample stones (as sl~ownhere). However, to~lrmalinehas not been reported in sapphires from other localities. Photomicrograph 0 Rol, Schwieger; mugnified 40 x ,

274 Kashmir Sapphires GEMS & GEMOLOGY Winter 1990 -~zre14. The Kashmir samples examined ---7- Figwe 15. More than half of ~11eKashmir sap- monly contained small, slightly corroded crys- phires studied were found to contain strongly tals wit11 i~ldentationsthat match earlier de- corroded crystals of what appear to be pla- scriptions of zircon. The smaller, black, cube- gioclase. Photomicrogruph 0 Rolf Scllwieger; like crystals shorn here on a zircon-lilw crystal magnified 63 x . in (I I

Figure 17. This group of euhedral crystals ob- Figure 16, Very common in the samples studied served in a very few of the I

Kashmir Sapphires GEMS & GEMOLOGY Wintcr 1990 275 from Pailin and Australia [Schubnel) 1977; Gu- belin and Koivulal 19861). At least one of these features was seen in each of the six pieces of sapphire rough obtained by the author in Kashmir. However! because of the possibility of overlap with other localities and the absence of diagnostic mineral inclusions in some stonesl it is usually the combination of inclusions with optical spectra that allows the safest determination of Kashmir origin.

Spectrophotometry.From among the Kashmir sap- phires studied! as well as from sapphires lznown to come from Cambodia (Pailin)!Thailand! Vietnam! Nigeria! Australia! Burma! Sri Lanlza! Montana! Brazil! and Chinal more than 400 optical spectra Figure 18. Fingerprint-like secondary healing planes were common in the Icoshmir stones ex- were obtained in the range 200 to 800 nm. With amined, but have also been found in sappl~ires regard to unheated sapphiresl clear differences can from other localities. Photomicrograph 0 l

276 Kashmir Sapphires GEMS & GEMOLOGY Winter 1990 WAVELENGTH (nm) WAVELENGTH (nm)

Figure 20. The spectrwn shown in figure 19 for an ~znheatedl

Kashmir Sapphires GEMS & GEMOLOGY Winter 1990 277 Figure 22. Before heai treatment (left), the 29-ct Kashmir sapphire was predominantly dark blue with various degrees of transparency. After treatment (right), the stone showed better transparency but also large colorless areas. Note as well the partial melting of the surface on this heat-treated stone. Photos by SSEF (left)and Michael Oldford (right). ing has been previously reported in the literature treatment process; we do not know whether treat- about heat treatment of sapphires from Kashmir, it ment at higher temperatures and/or for a longer seems that, given the rarity of Kashmir stones and time would not have changed these inclusions the unavailability of fine new material from this even more. Some of the crystal inclusions were source, the heat treatment of existing stocks of altered significantly [figure 23), which not only lesser quality material is a very real probability. provided clear evidence of heat treatment but also The 29-ct faceted stone (with SSEF, Gubelin, limited their usefulness as indicators of locality and AGL certificates that state that the sapphire is origin. On the basis of this one sample, I would of Kashmir origin) submitted for heat treatment speculate that microscopic features [especially was originally of zoned blue color ranging from crystal inclusions) are usually less origin diagnos- mostly very dark blue to areas of light blue and tic in a heat-treated stone than in one that has not with various degrees of transparency (figure 22, been so treated. left). It was placed in an alumina crucible and The spectrum of the sapphire also exhibited subjected to heat treatment, with an increase in marked differences in absorption before (again, see temperature of 5OC per minute until 1700° was figure 19) and after (figure 24) treatment, espe- reached and maintained for five hours. The speci- cially in the region of 360 nm. The relative men was not coated prior to heating. The resulting strengths of absorption maxima at 374 and 388 nm stone was zoned a somewhat lighter blue with (part of the 450 system) changed markedly. A shift large colorless areas, and there was a general of the absorption edge-with a weak "shoulder" at improvement in transparency (figure 22, right); 328 nm- to a shorter wavelength below 300 nm partial melting of the surface was readily apparent. was also apparent. Note, too, that the spectrum of Repolishing, of course, would remove the telltale the Kashmir sapphire after treatment is almost surface features, with a loss of no more than 3%- identical to that of a heat-treated Sri Lanlzan 4% of its original weight. To remove the colorless sapphire (again, see figure 21). Thus, spectral areas, however, would require a weight loss of as analysis is not useful in separating heated Kashmir much as 40%. In general, heat treatment of this sapphires from heated sapphires from Sri Lanka, stone did not result in overall improvement in which have the greatest commercial importance appearance. among treated sapphires. The fact that as many as Microscopy revealed that heat treatment did 95% of all sapphires currently on the market may produce some changes in the internal features of have been heat treated (see, e.g., Kammerlinget al., the stone. Color zoning was still visible, as were 1990) makes this test all the more meaningful for some of the ~'snowflake"formations of dust-like determining not only the locality origin of, but particles. It appears, however, that some of these also the absence of heat treatment in, a Kashmir dust-like inclusions were dissolved during the sapphire.

278 Kashmir Sapphires GEMS &. GEMOLOGY Winter 1990 LI" Figi~tfi23. Heat treatment significantly altered the appearance of this group of crystals (zircon and iiraninitef). They are shown here before (left) and after (right) the stone was treated. Photomicro- graphs 0 Rolf Schwieger; magnified 40 x .

allanite crystals; (6)zircon crystals with indenta- tions; and (7) strongly corroded plagioclase crys- tals. The crystalline inclusions are relatively rare, but the first two features are quite common. Color zoning similar 'to that seen in Kashmir sapphires has been observed in some sapphires from Pailin and some heat-treated sapphires from Sri Lanlza. While dust-like particles have been seen in sap- phires from other localities, they have not been observed to occur in the "snowflake" formations that are exclusive to Kashmir stones. Optical spectrophotometry not only differen- tiates basaltic from nonbasaltic sapphires, but it also provides the means to distinguish among

WAVELENGTH (nm) sapphires from different nonbasaltic localities, I I when studied by an experienced analyst equipped with comparison spectra. This is especially useful Figure 24. The spectrum of this 29-ct heat- treated Kashmir sapphire is significantly differ- to distinguish natural-color Kashmir stones from ent from that of the unheated stone (see figure similar-appearing treated-color Sri Lanlzan sap- 19) and almost identical to those of heat- phires. treated Sri Lankan sapphires (see, e.g., figure It is likely that some Kashmir sapphires have 21). Transmittance spectrum, extraordinary ray. been subjected to heat treatment. It appears, how- ever, that the damage to crystalline inclusions and the marked differences in optical spectra caused by exposure to high temperature make it extremely CONCLUSION difficult to establish conclusively the locality The locality origin of natural blue sapphires from origin of a heat-treated Kashmir sapphire. Kashmir can, in many cases, be positively identi- fied through a combination of microscopic exam- ination and optical spectrophotometry. The char- acteristic features that can be seen with a micro- scope (using strong fiber-optic illumination) are: REFERENCES (1)distinctive color zoning; (2)clouds andlor lines Atkinson D., Kothavala R.Z. (1983)Kashmir sapphire. Gems el Gemology. Vol. 19, No. 2, pp. 64-76. of dust-like particles in a "snowflake" formation; Bauer M. (1904) Precious Stones. Trans. by L. H. Spencer, (3)pargasite crystals; (4)tourmaline crystals; (5) Charles Griffin and Co., London.

Kashmir Sapphires GEMS & GEMOLOGY Winter 1990 Bauer M. (19321Edelsteinkunde, 3rd ed. K. Schlossmacher, Ed., Kammerling R.C., Koivula J.I., Kane R.E. (1990) Gemstone B. Tauchnitz, Leipzig. enhancement and its detection in the 1980s. Gems el Bosshart G. (19821Distinction of natural and synthetic rubies Gemology, Vol. 26, No. 1, pp. 32-49. by ultraviolet spectrophotometry. Io~irnalof Gemmology, Phukan S. (1966) Studies on inclusions in some Indian gem- Vol. 18, No. 2, pp. 145-160. stones. journal of Gemmology, Vol. 10, No. 1, pp. 1-7. Brown J.C. (1956) Sapphires of India and Kashmir. Gemmolo- Schmetzer K. (19851Distinction of natural and synthetic rubies gist, Vol. 25, No. 298, pp. 77-80, by ultraviolet absorption spectroscopy-possibilities and Fritsch E., Rossman G.R. (19901New technologies of the 1980s: limitations of the method. Zeitsclirift der Deutschen Their impact in gemology. Gems a) Gemology, Vol. 26, No. Gemmologischen Gesellschaft, Vol. 34, pp. 10 1-1 29. 1, pp. 64-75. Schmetzer K. (19861 Naturliche und Synthetische Rubine. E. Giibelin E.J. (19481 Die diagnostische Bedeutung der Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Ger- Einschlusse in Edelsteinen. Schweizerisch Miner- many. alogische und Petrographische Mitteilungen, Vol. 28, No. Schmetzer K., Bank H. (1981)Die Farbursachen und Farben der I, pp. 146-156. Mineralart Korund. Zeitschrift der Deutschen Gem- Gubelin E.1. (1953) Inclusions as a Means of Gemstone Identi- niologischen Gesellschaft, Vol. 30, No. 314, pp. 152-156. ffcalion. Gen~ologicalInstitute of America, Los Angeles, Schubnel H.-J. (19671 Determination of solid inclusions in CA. gemstones. journal of Gemmology, Vol. 10, No. 6, pp. Gubelin E.J. (1973) Innenwelt dei Edelsteine. ABC Verlag, 189-193. Zurich. Sch~~bnelH.-J. (19721Pierres Precieuses Dans le Monde. Hori- Giibelin E.J. (19851 Kashmir sapphire (in German]. Lapis, No. zons de France, Paris. 10, pp. 11-22. Smith H.G.F. (19121Gemstones and Their Distinctive Charac- Giibelin E.J., Koivula 1.1. (19861 Photoatlas of Inclusions in ters. Methuen & Co., London. Cernstones, ABC Edition, Zurich. Stern WB., Hanni H.A. (19821 Energy dispersive X-ray spec- Halford-Watkins J.F. (19351 Kashmir sapphires. Gemmologist, trometry: A nondestructive tool in gemmology. lournal of Val. 4, NO. 42, pp. 167-172. Gemmology, Vol. 18, No. 4, pp. 285-296. Hinni H.A. (19901A contribution to the distinguishing charac- Streeter E.W. (1884)Precious Stones and Gems, 4th ed. George teristics of sapphire from Kashmir, Journal of Gemmology, Bell & Sons, London. Vol. 22, No. 2, pp. 67-75.

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Kashmir Sapphires 280 GEMS & GEMOLOGY Winter 1990 NOTES AND NEW TECHNIQUES

AN INVESTIGATION OF A SUITE OF BLACK DIAMOND JEWELRY By Robert C. Kammerling, Robert E. Kane, John I. Koivula, and Shane F. McClure

This article reports on the gemological properties of (1977, p. 113) described blaclz diamonds as resem- six large black diamonds set in a suite of jewelry. bling hematite, having no visible inclusions and The color of the diamonds was determined to be being deeply colored throughout. He speculated caused by numerous black inclusions lining cleav- that the color "may be due to partial changes in the ages and fractures. Such stones are difficult to cut crystal structure and the formation of finely dis- and polish, and require great care in setting. They persed graphite particles, invisible even at very can be separated from artificially irradiated dark high magnifications." Subsequently, however, green black-appearing diamonds and from other black mi black-appearing materials on the basis of Bruton (1978, p. 390) described blaclz diamonds as their distinctive visual and gemological features. being "usually translucent to very strong light" and often having gray spots. He attributed the blaclz color to "their very large number of very small or sub-microsconic blaclz inclusions which absorb nearly all the light falling on the stone." Reports in the gemological literature have de- Later (1986, pp. 110-1 11))Bruton expanded on the scribed diamonds in a great variety of colors and controversy: "Prominent diamantaires have long have ascribed the causes of these colors to a declared that there are no black diamonds-that number of mechanisms. According to the compre- they exist only in detective stories. The origin of hensive review by Fritsch and Rossman (1988), this belief may be that some so-called blaclz these include structural defects of unknown origin diamonds are actually dark brown with so many (which produce purple, pink to red, and brown specks of dark mineral inclusions that they only colors in diamond); band transitions caused by the appear blaclz." In some cases, artificial irradiation presence of boron (which are responsible for blue); a general radiation (GR1) center (neutral carbon vacancy) plus defects that absorb in the red (which cause green); and aggregated or isolated nitrogen ABOUT THE AUTHORS impurities (resulting in yellow). Mr. Kammerling is director of technical development, and Mr. However, relatively little has been written Koivula is chief gemologist, at the Gemological Institute of about blaclz diamonds and even less about the America, Santa Monica, California. Mr. Kane is supervisor of cause of their color. Some of the information that is gem identification, and Mr. McClure is senior staff gemologist, in the GIA Gem Trade Laboratory, Santa Monica. available is contradictory or incomplete. An early The authors wish to thank Jean-Pierre Kuntz of Marina del Rey, reference ("Black Diamonds," 1934, p. 86)reported California, for providing the opportunity to examine and photo- that blaclz diamonds are opaque, with a structure graph the suite of black diamond jewelry shown in figure 1. "like fine-grained steel." They "are not used as Gems & Gemology, Vol. 26, No. 4, pp. 282-287 gems, but solely for industrial purposes." Orlov @ 1991 Gemological Institute of America

282 Notes and New Techniques GEMS & GEMOLOGY Winter 1990 Figure 1. The six black diamonds in this impressive suite were studied for this report. The larg- est stone measured approx- imately 19.20 mm x 20.70 rnm x 9.60 mm. Jewelry courtesy of lean-Pierre Kuntz; photo by Shane P. McClure.

may produce a green color that is so dark that the drawn with regard to the cause of color in these six diamond appears to be black (Liddicoat, 1989). stones and to the features that can be used to Some notable blaclz diamonds are known, but separate them both from artificially irradiated the mechanism(s) responsible for their color has black-appearing diamonds and from other blaclz not been studied in detail. These include the Blaclz gemmaterials with which they might be confused. Star of Africa, at 202 ct reportedly the largest of this color (Br~iton,1986); and the Black Orloff, a GEMOLOGICAL PROPERTIES 67.50-ct cushion-shaped stone that has been de- Visual Appearance. Several interesting observa- scribed as having a "gunmetal" color (Bruton, tions were made with the unaided eye using 1986; Balfour, 1987). overhead illumination (both incandescent and flu- Recently, the authors had the opportunity to orescent). The body color as observed in oblique examine a suite of jewelry that featured six bril- incident light could best be described as black. The liant-cut black diamonds (figure l):a pendant with luster of all six stones, as expected for diamond, a heart-shaped blaclz diamond measuring approx- was adamantine. The authors agreed that both the imately 19.20 x 20.70 x 9.60 mm; a ring with a dark body color and (lack of) transparency contrib- round center stone measuring approximately uted to the high luster, which gave the stones an 16.05-16.20 x 10.02 mm; and a pair of clip-back almost metallic appearance. As would be expected drop earrings, each containing two round blaclz for diamond, the facet junctions were extremely diamonds ranging from 11.0-1 1.2 x 7.85 mm to sharp, unlike what would be seen on a gem 12.7-12.8 x 9.6 mm. All of these stones were material with a very dark body color and high subjected to standard gemological tests and exam- luster but lower hardness, such as "Alaskan blaclz ined with the microscope. The results of these diamonds," a misnomer sometimes used for fac- tests are provided below, and conclusions are eted hematite. Careful examination revealed that

Notes and New Techniques GEMS &. GEMOLOGY Winter 1990 283 Figure 2. Even with the unaided eye, numerous Figure 3. Artificially irradiated black-appearing breaks can be seen reaching the surface of the diamonds typically reveal a dark green colora- black diamonds, as illustrated here by one of tion through thin, relatively transparent edges the round brilliants. Photo by John I. Koivz~la; when examined with intense illumination. This oblique illumination. treated diamond, however, appeared green throughout most of the stone, even under the table as shown here. Photomicrograph by all six stones were heavily variegated, consisting of Robert E. Kane; magnified 10 x . a few transparent areas surrounded primarily by opaque zones that are caused by dense concentra- tions of blaclz inclusions. Also evident to the shaped stone in the pendant showed numerous unaided eye were small cavities and irregular areas (some large) that transmitted light and interconnecting fissures on the surfaces of these ranged from light gray to colorless. At certain stones (figure 2). positions the fiber-optic light pipe caused a blue luminescence (as is seen in "Jager diamonds," an Transmission of Light. It is the authors' experience old trade term for colorless diamond with a strong that the only conclusive method of determining if blue fluorescence) in the transparent areas of the the color of a blaclz diamond results from artificial heart-shaped diamond (figure 4) and in the upper irradiation is to pass light through a thin edge, such diamond of one of the earrings. as at the girdle or culet. Artificially irradiated "black" diamonds exhibit a very dark green color (figure 3) at the thin edges and in the relatively Figure 4. The transparent areas of the heart- transparent areas when examined using a 150-watt shaped black diamond luminesced blue to an tungsten-halogen fiber-optic illuminator or when intense fiber-optic light source. Photomicro- placed over the intense tungsten-halogen base graph by Robert E. Kane; magnified 15 x . light on a GIA GEM spectroscope unit [Liddicoat, 1989). A fiber-optic illuminator placed perpendicular to the table under each of the mounted black diamonds revealed the following: The diamond in the ring was almost completely opaque, with only a very few, minute areas allowing the passage of white light; the lower stone in one of the earrings was also almost totally opaque, with even fewer transparent areas than the stone in the ring; the other three black diamonds in the earrings all showed several small areas that were transparent and appeared essentially colorless; the heart-

284 Notes and New Techniques GEMS & GEMOLOGY Winter 1990 Microscopic Features. As with virtually all of the graphite when viewed with transmitted or darlz- natural blaclz diamonds the authors have collec- field illumination, and may be found in cleavages tively examined, the polish on these six stones was and fractures immediately surrounding silicate poor. The facets were pitted and covered with and sulfide inclusions. However, they have an prominent polishing and drag lines, which would entirely different appearance (i.e., brassy yellow appear to be due to the abundance of cleavages, compared to the characteristic gray of graphite) fractures, and inclusions that break the surfaces of when oblique illumination is used. We know of no the stones (figure 5). It is generally lznown in the published report where oxides or sulfides that trade that blaclz diamonds arevery hard to polish resemble graphite have been seen to line the faces and can damage polishing lap. of extensive surface-reaching cleavage and fracture systems of the type observed in these "black" diamonds. Therefore, we concluded that the inclu- sions in these diamonds were graphite. Because the stones were so heavily cleaved and fractured, we decided that the potential for damage was too great to attempt to obtain a scraping for X-ray diffraction analysis. Unfortunately, the client could not leave the suite in the laboratory for the time needed to perform chemical analysis on this material.

Absorption Spectra. The visible-light absorption spectra (400 to 700 nm) of the six blaclz diamonds were examined using a hand-held type of Beck prism spectroscope, first at room temperature and then cooled with an aerosol refrigerant to approx- imately - 65OFI - 54'C. Because the diamonds were essentially opaque, the external reflection Figure 5. The numerous pits and polishing and method of spectroscope lighting was used. At drag lines seen on all the black diamonds stud- either room or low temperature, we observed no ied for this report are evident on this stone. Photomicrograph by Robert E. Kane; coaxial illumination, magnified 15 x . Figure 6. Numerous minute black inclusions lining cleavages and fractures were responsible Examination of near-surface areas and thin for the almost opaque nature of the black dia- edges revealed that the opacity of the stones was monds. Photomicrograph by Robert E. Kane; due to numerous minute blaclz inclusions that oblique illumination, magnified 20 x . lined the extensive system of cleavages and frac- tures (figure 6). In one area on the heart-shaped stone that was covered with these opaque blaclz inclusions, a minute part of a small cleavage plane was exposed on the surface. Careful application of a needle probe to this small section revealed that these inclusions had the platy texture and easy cleavage characteristic of graphite, in addition to the typical blaclz color. It is lznown that cleavage and fracture systems in diamonds can become lined with graphite through the process of graphi- tization, in which the surface layer of diamond in the breaks is converted to graphite (Harris, 1968; Harris and Vance, 1972). Some sulfides, such as pyrrhotite and pentlandite, may look similar to

Notes and New Techniques GEMS & GEMOLOGY Winter 1990 285 distinct lines or bands in any of the six blaclz reaction was quite different from that described diamonds. above: a very weak, chalky greenish yellow over It should be noted that treated green blaclz- most of the stone, again with some mottling. The appearing diamonds may on very rare occasions large stone in the ring and both stones in the other reveal the treatment-associated 595-nm line in the earring were inert to both long- and short-wave hand-held spectroscope. U.V radiation. When we examined the stones with magnifica- Ultraviolet Fluorescence. Some of the blaclz dia- tion, we saw that all had been glued into their monds displayed a very unusual reaction to long- mountings. This was evident from the numerous and short-wave ultraviolet radiation. The heart- gas bubbles present in the glue. The glue was also shaped stone in the pendant and the top stone in marked by the white fluorescent line it produced one of the earrings (the same stone that showed a around portions of the girdle when the pieces were blue luminescence with transmitted light) exhib- exposed to both long- and short-wave ultraviolet ited a strong blue fluorescence to long-wave U.V radiation. The long-wave reaction, however, was radiation that formed very distinct patches and the stronger of the two. The authors hypothesize veins, intermixed with inert areas (figure 7). The that the diamonds were glued into their mountings sections that fluoresced seemed to correlate to the because of concern that any pressure from setting more transparent areas of the stones. These same might cause these highly cleaved and fractured sections fluoresced a moderate chalky greenish stones to break. yellow to short-wave U.V radiation. Although still very mottled, the short-wave fluorescence was Streak. All six of the blaclz diamonds cut easily even more extensive than the long-wave fluores- into the streak plate without leaving any residue. cence: There were very few inert areas. The other black stone in the same earring also Thermal Conductivity. All six black diamonds fluoresced to long-wave U.V radiation, but the registered well within the "Diamond" range on a GIA GEM Instruments pocket diamond tester.

Refractive Index. As is the case with all diamonds, the refractive indices of all six study stones were Figure 7. The heart-shaped blacli diamond and over the limits of the conventional refractometer the upper blacli diamond in one of the earrings fluoresced an uneven, strong blue in distinct (1.80 or 1.81). patches and veins, intermixed with inert areas, to long-wave U.V, radiation. Photo by Shane F. SEPARATION FROM McClure. POSSIBLE SIMULANTS There are some blaclz or black-appearing gem materials that, because of their relatively high luster, might be visually confused with blaclz diamonds. Table 1 summarizes the distinguishing properties of black diamonds and these other materials. CONCLUSION The six blaclz diamonds examined for this report all contained extensive cleavagelfracture systems that were lined with black inclusions that are believed to be graphite. The presence of these inclusions is undoubtedly responsible for the blaclz color exhibited by these stones. The fact that the areas of transparency in these stones were color- less and the absence of a 595-nm line in the spectroscope served to separate them from arti-

286 Notes and New Techniques GEMS & GEMOLOGY Winter 1990 TABLE 1. Comparison of natural black diamonds to gem materials with which they may be confused^

Mohs Material R.I. S.G. hardness Luster Additional features

Black Adamantine With magnification, numerous black diamond inclusions can be seen lining cleavages and fractures; nonincluded areas are transparent and range from light gray to colorless Irradiated 2.417 3.52 10 Adamantine Dark green color in transmitted "black light; may rarely show a 595-nm diamond absorption line in spectroscope Hematite Approx. 3.0 5.08-5.20 5.5-6.5 Metallic Reddish brown streak, splintery fracture Imitation Over limits of 4.00-7.00 2.5-6.0 Metallic Dark brown to black streak, hematite conventional granular fracture, magnetic refractometer; no measured data available Melanite Subadamantine Conchoidal to uneven fracture, (titanian to vitreous white to gray streak andradite garnet) Psilomelane Metallic to May be banded; conchoidal with submetallic fracture, white to gray streak chalcedony Black Adamantine to White, grayish, or brown streak, cassiterite submetallic or subconchoidal to uneven fracture

e ' vitreous YIG (yttriqm- No measured Approx. 6 No measured Vitreous to Strongly attracted to magnet, does iron garnet) data available data available submetallic not exhibit electrical conductivity Uraninite No measured 7.5-10.0 5-6 Submetallic, also Causes radiation burns if worn, will (pitch blen'de data available (single crystals) resinous to generate autoradiograph; fracture is in massive 5.2-9.0 greasy conchoidal to uneven, streak is form) (pitchblende) black, brownish black, gray, or brownish green

,'Â¥Thiinformation is based on the six stones examined tor this article. The properties of the other gem materials are as reported in Liddicoat (1989).

ficially irradiated black-appearing diamonds, Bruton E. (1986) Legendary Gems or Gems that Made History. which are in reality a very dark green. They can be Chilton Book Co., Radnor, PA. Fritsch E., Rossman G.R. (1988) An update on color in gems. separated from other black or black-appearing Part 3: Colors caused by band gaps and physical phenom- materials on the basis of their distinctive gem- ena. Gems o) Gemologx Vol. 24, No. 2, pp. 81-102. ological properties. Harris J.W (1968)The recognition of diamond inclusions. Part 2: Epigenetic mineral inclusions. Industrial Diamond Re- view, Vol. 28, No. 335, pp. 458-4611, Harris J.W, Vance E.R. (1972) Induced graphitisation around crystalline inclusions in diamond. Contributions to Min- REFERENCES eralogy and Petrology, Vol. 35, pp. 227-234. Liddicoat R.T. (19891 Handbook of Gem Identification, 12th Balfour I.(1987) Famous Diamonds. William Collins Sons Co., ed., 2nd rev. printing. Gemological Institute of America, Glasgow, Scotland. Santa Monica, CA. Black diamonds (19341. Gemmologist, Vol. 4, No. 39, p. 86. Orlov Y.L. (1977)The Mineralogy of the Diamond. JohnWiley &. Bruton E. (1978) Diamonds. Chilton Book Co., Radnor, PA. Sons, New York.

Notes and New Techniques GEMS & GEMOLOGY Winter 1990 287 "EMERALDOLITE": A NEW SYNTHETIC EMERALD OVERGROWTH ON NATURAL BERYL By Dominique Robert, Emmanuel Fritsch, and John I. Koivula

This article describes a new manufactured gem mate- rial marketed under the trade name "Emeraldolite," which is an epitaxial growth of flux synthetic emer- ald on opaque white beryl. The material has a dis- tinctive visual appearance, and is commonly used for jewelry in its "rough" form. The gemological proper- ties of "Emeraldolite" are very similar to those nor- mally shown by flux-grown synthetic emeralds.

n Emerald~lite~~is a new manufactured gem mate- rial that consists of a substrate of common opaque white natural beryl with an epitaxial deposit of flux-grown synthetic emerald (figure 1).Although it is not presently being produced in commercial quantities, the capacity exists for a large-scale operation. It has been used in jewelry in its "natural" form, but is also fashioned en cabochon. Unlike most synthetic emeralds, it is usually not faceted because of its opacity. This article provides a general description of the procedure used to produce this new manmade gem material, and reports on its gemological properties and chemistry.

METHOD OF SYNTHESIS "Emeraldolite" is manufactured by one of the Figure 1. This 76.42-ct "Emeraldolite" specimen authors (D.R.)in France. A flux process (a chemical consists of a flux-grown synthetic emerald over- reaction in anhydrous solvents) is used to produce growth on natural white beryl. Photo by Robert the synthetic emerald overgrowth on a natural Weldon. beryl seed; fluoroberyllate compounds play an important role (see Robert, 1987). The resulting product is reminiscent of the The flux process that produces the synthetic Lechleitner overgrowth of hydrothermal emerald emerald overgrowth for "Emeraldolite" is also on prefaceted colorless beryl (see, e.g., Schmetzer significantly different from that used to grow et al., 1981).Both are based on the same principle: synthetic emeralds such as the Lennix product (see the synthesis of an epitaxial overgrowth on less Graziani et al., 1987).In the Lennix process, A1203 expensive beryl, rather than the (more costly and and SiO, are dissolved from the crucible itself, and more time-consuming) synthesis of an entire the flux is a typical mixture of lithium molybdate stone. The two products vary greatly in appear- and a boron salt. By contrast, the synthetic emer- ance, however, with the Lechleitner material usu- ald layer in "Emeraldolite" is grown using a chemi- ally translucent to transparent, while virtually all cal - not a physical - reaction involving fluorine as of the "Emeraldolite" produced to date has been a transport agent. This allows for faster growth opaque. than the Lennix process. Further information on

288 Notes and New Techniques GEMS & GEMOLOGY Winter 1990 the procedure use to grow "Emeraldolite" must remain proprietary.

CURRENT PRODUCTION Because "Emerald~lite~~only requires the growth of a thin (0.3-1 mm) layer of synthetic emerald, it is relatively inexpensive to manufacture (see "Syn- thetic emeralds . . . ," 1988). With only a small furnace, 15,000-20,000 ct of material can be produced annually. The process could be adapted to accommodate larger production in a variety of shapes and styles. Presently, production is variable, with ongoing experimentation into the most at- tractive product for jewelry use. It has been found, for example, that the overgrowth is unpleasantly asymmetrical on all isometric shapes, such as spheres, because of preferred growth along the optic axis. Figure 2. A different view of the specimen in figure 1 shows the thin flux synthetic emerald DESCRIPTION OF THE MATERIAL overgrowth. The color contrast between the A view from the base of the "Emeraldolite" sample white seed and the overgrowth is obvious. The in figure 1 shows a thin layer of transparent dark numerous parallel crystal faces demonstrate the green, flpx-grown synthetic emerald covering a epitaxial character of the overgrowth. Photo by milky-white natural beryl crystal (figure 2). The Robert Weldon. substrate, which plays the role of seed crystal, can be of any size or shape. The linear dimension of the beryl core used is not a critical parameter (pieces over 10 cm have been successfully processed); Before deposition of the overgrowth, the sub- rather, the total surface area is key because it strate can be preformed in a particular shape determines the amount of feed material necessary [cabochon, for example) to fit in standard mount- to obtain a smooth, homogeneous coverage. ings. The "Emeraldolite" can then be polished The dark color of the overgrowth is very even, (with greater ease than if the overgrowth were and is reproducible from run to run. The synthetic random, because there is only one crystallographic emerald layer has a step-like appearance caused by orientation) or incorporated as grown into pieces of the juxtaposition of numerous tiny (1-5 mm in jewelry (figure 3). Even polished, though, the sur- longest dimension) crystal faces that are all ori- face is irregular, so visual appearance will easily ented in the same crystallographic direction. This separate "Emeraldolite" from natural emerald and crystallographic orientation also contributes to even other synthetic emeralds. the homogeneity of color. GEMOLOGICAL PROPERTIES To characterize lfEmeraldolite" gemologically, we studied a total of 10 samples: one large (37.94 x ABOUT THE AUTHORS 24.3 1 x 18.13 mm; 76.42 ct), very dark, irregular Mr. Robert is a consulting engineer and professor at the St. Etienne School of Mines, St. Etienne, France. He has done ex- crystalline mass (figure 1);five smaller (20 mm in tensive research in crystal growth, and currently manufactures maximum dimension) rough pieces; one 20-mm both "Emeraldolite" and "Oulongolite." Dr. Fritsch is research piece polished as a flat tablet; and three "rough" scientist, and Mr. Koivula is chief gemologist, at the Gernologi- cal Institute 01 America, Santa Monica, California. pieces that had beenmounted in jewelry (again,see figure 3). The results of our examination are Acknowledgments: The authors are grateful to Robert Weldon of GIA for taking photographs of the material studied, and to summarized below. In general, the gemological Dr. James Shigley of GIA for his constructive comments, properties of the "Emeraldolite" overgrowth are Gems & Gemology, Vol. 26, No. 4, pp. 288-293 consistent with those of other flux-grown syn- 0 1991 Gemological Institute of America thetic emeralds (Koivula and Keller, 1985).

Notes and New Techniques GEMS & GEMOLOGY Winter 1990 289 with no visible phosphorescence. This contrasts with the weak red fluorescence typical of most flux-grown synthetic emeralds. Although the iron content of the material is relatively low (0.28-0.34 wt.% FeO; see "Chemical Analysis" below), other synthetic emeralds containing similar amounts of iron do fluoresce red (Koivula and Keller, 1985; Graziani et al., 1987). Quenching by vanadium is possible, but unlikely. Instead, the absence of fluorescence may be due to "self-quenching," which occurs when nearby ions of the same type (here, Cr3+ ions) interact because of their high concentration, and the energy absorbed is given off in a form other than visible luminescence (Way- chunas, 1988). The surfaces of several specimens are speckled Figure 3. These three pieces of "Emeralddite" with numerous tiny, -white, translucent, octa- jewelry represent a typical style in which this hedral crystals (figure41 and crusts of what appears new gem material is employed. The ma1 to be "lithium feldsparti-the type of crystals piece measures 5.5 x 3.5 cm.Photo by Robert obtained by Hautefeuille and Perrey when they Weldon, fast synthesized emerald by a flux method in 1888 [Nassau, 1976). These spots fluoresce a weak, Refractive Index. Because the essentially rough chalky, brownish yellow to long-wave U.V radia- surface is covered with tiny crystal faces, we used tion, and a strong, chalky, slightly brownish yellow the spot method (ona Duplex II refsactometerwith to short-wave U.V a white light source) on foul different areas of the large crystal and one spot on each of the other Visible-Light Spectroscopy. Using a Pye Unicam pieces. All yielded an R.I. of 1.56, which is typical 8800 spectrophotometer, we took the visible-light of flux synthetic emerald (Liddicoat, 1989; p. 101}. absorption spectrum of a small fragment of the Because of the limitations imposed by the irregular synthetic emerald overgrowth in a random orien- surface condition of the "Emeraldolite,"no bire- tation. The spectrum produced is typical of syn- fringence could be determined. thetic emerald: two broad bands with apparent maxima at about 430 and 6 10 nm,and a number of Specific Gravity. We could not determine an accu- rate specific gravity on any of the study specimens because the irregular surfaces trapped excessive Figme 4. 'liansiucmt, white, octahedral "It- amounts of air that could not be completely tbiuna feldspar" crystals form as a by-product dislodged. Moreover, the specific gravity of an oa and in the "Emeialdolite"overgrowth. Photo- entire piece of "Emeraldolite"would vary depend- micrograph by John I. Koivvia; magnified 30 x . ing on the specific gravity of the core. We did, however, test a 0.05-ct fragment of the synthetic overgrowth, using a mixture of methylene iodide and benzyl benzoate calibrated at 2.67. The sample floated very slowly to the surface of the liquid, on the basis of which we estimated the S.G.to be 2.66, which is typical of flux-grown synthetic emerald (Liddicoat, 1989; p. 101).

Ultraviolet fluorescence, When examined in dark- room conditions with both long- and short-wave ultraviolet radiation, the synthetic emerald over- growth and the white core material were inert,

290 NO& and New Tschoiques GEMS & GEMOLOGY Winter 1990 sharp bailds at 470,476,636,660,680, and 683 nm. "Cr lines" were easily seen with a, Be& hand spectfoscope.

Plwehroism, Although "Emeralcblite" is essen- tially opaque and very dark, we did see moderate pleocbioism (very slightly yellowish green and bluish green) when all specimens were viewed through a dichroscope with reflected light.

Chelsea Color Filter Reaction. When bathed in white light from a fiber-optic illuminator and examined with a Chelsea color filter, the surfaces tense brownish red. aid overgrowth layer contrasts with the uader- lying white beryl substrate. Photomicrograph Hardness. Using a set of Mobs hardness points, we b7 Job L maspified 6 x a found that "Emeraldolite" was easily scratched with the corundum point (hardness 91, but the topaz point (hardness8) did not produce a scratch even when a reasonable amount of pressure was prism, faces and basal planes. The occurrence of applied. We therefore estimated the Mohs haid- bipyrarnidal faces is strongly related to the some- ness to be approximately 8, which is within the what complicated end of the thermal synthesis expected range for synthetic emerald. cycle. These faces are less common in the firnap- oration, fades" obtained on the surface of the melt ~~ss,The epitaxial growth process smto and on the dsof the crucible (Robert, 1987].A begin with a short etching period that guarantees detailed description of the crystal shapes and complete continuity between the crystalline lat- associations is given in Robert ( 1988a and b). Note tice of the substrate and that of the overgrowth. that the stress cracks typical of the hydrother- This results in a very good toughness and median- may grown Lechlfiitner synthetic emerald over- ical solidity that would not be achieved if the growth were not seen in the flux overgrowth of emerald overgrowth had a random orientation. "Emeraldolite." The overgrowth cannot be broken off the sub- The small, colorless octahedral crystals of "li- strate, so the toughness of "Emeraldolite" is ba- thium feldspar" that were seen to fluoresce on the sically that of the substrate. If this latter contains surface of the samples were also seen inside the big fractures, it will shatter when put in the flux;if synthetic emerald overgrowth. This "lithiumfeld- it contains small fractures, the epitaacy will seal spar" crystallizes in the tetragonal system, and its them, reinforcing the piece. crystal structure is currently under study. In the synthetic emerald layer, we also observed Mmoscepic Features, Using oblique illumination, comparatively large primary flux inclusions of an we caremy examhed the transparent ov~owth OH-whiteto brown color [&we 61, as well as h&- of the "Emeraldolite"samples with a gemological relief spherical to subspherical voids that greatly mimope.fie features observed can te used to resemble the odhmy gas bubbles common to identify this material as a synthetic. most glasses (figure 71. The latter may be pafdally Specifically magnificationrevealed several fam- open at the surface, forming crater-like pits. Al- ilia of tiny parallel cryeta1faces that cover the flux though die flux inclusions were typical of those synthetic overgrowth layer like a mosaic. In some observed in flux-grown synthetic emeralds (Gii- few areas, the overgrowth had been chipped away, belin and Koivula, 19861 the bubble-like features exposing the white beryl substrate (figures 2 have not been seen before in synthetic emeralds and 5). and are more characteristic of inclusions found in The morphology of the emerald crystals in the the Kmschka synthetic ruby (Gobelin, 19821, also overgrowth is typical of emerald, with essentially a flux product.

Notes and New Techniques GEMS & GEMOLOGY Winter 1990 291 Figure 6. These primary flux inclusions were commonly observed in the "Emeraldolite" over- growth. Photomicrograph by John I. Koivula; Figure 7. High-relief spherical to szzbspherical magnified 20 x . voids are commonly seen in the "Emeraldolite" overgrowth layer. Photomicrograph by John I. IZoivula; magnified 50x. CHEMICAL ANALYSIS Using an energy-dispersive electron microprobe, Dr. Henry Hanni and George Bosshart, both at the 13.20 wt.74, Schmetzer et al., 1981). These high time with the Swiss Foundation for Research on concentrations of Cr3 + are responsible for the dark Gemstones [SSEF),analyzed the chemistry of the green color. The low concentrations of magnesium "Emeraldolite" epitaxial overgrowth. The range of also contrast with the high values [more than 0.8 compositions obtained is shown in table 1. wt.% MgO] found in natural emeralds. Concentra- Note in particular that the concentration levels tions of Na20 in "Emeraldolite" compare favorably of Cr3+ are significantly higher than those found with those of synthetic emeralds (less than 0.2 in most natural emeralds (approximately 1 wt.%; wt.%) and contrast with the 0.4 wt.% usually Hanni, 19821, but are lower than those found in the found in natural emeralds (Hanni, 1982). Lechleitner synthetic emerald overgrowth (7.64 to The higher concentrations of Mg and Na in nature are due to Mg2+ substituting for Al3+ in the beryl crystal structure, the charge deficit being

compensated by the presence of a Na + ion nearby. TABLE 1. Chemical composition of the "Emeraldolite" synthetic emerald overgrowth.= This mechanism does not occur during the growth of the "Emeraldolite" layer or any flux-grown Oxide Weight % synthetic emerald because Mg and Na are not 66.88 - 67.28 voluntarily introduced in the growth environ- 16.58- 18,21 ment. nd - 0.06 0.28- 0.34 CONCLUSION 0,17- 0.25 Manufactured in France, "Emeraldolite" is an nd - 0.13 overgrowth of deep green flux synthetic emerald 1.76- 4.15 on opaque white natural beryl. It is based on a nd - 0,12 principle similar to that of the Lechleitner syn- bdl thetic emerald overgrowth on transparent to trans- Chemical analyses performed by Henry Hanni and George Bosshart, lucent near-colorless natural beryl. Its unique SSEF, on an electron microprobe equipped with an energy-dispersive appearance makes it easy to separate from any spectrometer. Details of the operating conditions can be obtained from the analysts. nd = not determined; bdl= below detection limits. other natural gem or synthetic material. In addi- tion, one can find in the synthetic emerald over-

292 Notes and New Techniques GEMS & GEMOLOGY Winter 1990 growth characteristics typical of a flux-grown because its numerous crystal faces reflect light synthetic emerald. well. The material can, however, be polished, and "Emeraldolite" has been used by jewelry manu- lends itself to intarsia and sculpture, as well as to facturers in its original state, without polishing, cabochons.

REFERENCES Graziani G., Gubelin E., Martini M. (1987) The Lennix syn- 35, pp. 21 1-222. thetic emerald. Gems a) Gemology, Vol. 23, No. 3, pp. Robert D. (19871 Genkse du bervl. svnthkse de 1'6n1eraude. 140-147. ~ondea) Iviindraux, No. 80,';~ 39-42. Gubelin E.J.(1982) New synthetic rubies made by Professor I? 0. Robert D. (1988a)LIEmeraldolite, line nouvelle matiere. Revue Knischka. Gems a) Gemology, Vol. 18, No. 3, pp. 165-168. de Gemmologie a.f.g., No. 94, pp. 9-10. Gubelin E.J., Koivula J.I. (1986) Photoatlas of Inclusions in Robert D. (1988b)Qu'est-ce que llEmeraldonite [sic]. Revue de Gemstones, ABC Edition, Zurich, Switzerland. Gemmologie u.f.g., No. 95, pp. 19-20. Hanni H.A. (1982)A contribution to the separability of natural Schmetzer K., Bank H., Stable V (1981)The chromium content and synthetic emeralds. Journal of Gemmology, Vol. 18, of Lechleitner synthetic emerald overgrowth. Gems çs NO. 2, pp. 138-144. Gemology, Vol. 17, No. 2, pp. 98-100. Koivula J.I., Keller PC. (1985) Russian flux-grown synthetic Synthetic emeralds: New growth in an ancient gem (1988). emeralds. Gems et) Gemology, Vol. 21, No. 2, pp. 79-85. Solitaire, November, pp. 27-30. Liddicoat R.T. (1989) Handbook of Gem Identification, 12th Waychunas G.A. (19881Luminescence, X-ray emission and new ed., 2nd rev. printing. Gemological Institute of America, spectroscopies. In F. C. Hawthorne, Ed., Spectroscopic Santa Monica, CA. Methods in Mineralogy and Geology, Reviews in Mineral- Nassau K. (1976)Synthetic emerald: The confusing history and ogy. Vol. 18, Mineralogical Society of America, Washing- the current technologies. fournal of Crystal Growth, Vol. ton, DC, pp. 635-698, C'

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Notes and New Techniques GEMS & GEMOLOGY Winter 1990 293 EDITOR C. W. Fryer Gem Trade Laboratory, West Coast CONTRIBUTING EDITORS Robert Crowningshield LAB NOTES Gem Trade Laboratory, East Coast Karin N. Hurwit Gern Trade Laboratory, West Coast Robert E. Kane Gern fracVe Laboratory, Wes t Coast David Hargett Gem Trade Laboratory, East Coast

AZURITE clinic system, and can vary widely in blue subparallel sharp-edged crystals habit and be highly modified. Among (figure 1). Azurite is almost invaria- The West Coast laboratory recently the most attractive specimens are bly found in conjunction with mal- had an opportunity to examine sev- the nearly spherical aggregates or achite; some of these specimens can eral collection-quality specimens of rosettes that exhibit numerous deep be quite exceptional (figure 2). RIZ azurite, the theme mineral of the 1991 Tucson Gem &Mineral Society Show. These fine specimens came Figure 1. This fine azurite cluster (10 x 7.6 cm) is reportedly from from several different localities. one of the world's earliest exploited copper deposits, near Lyon, Azurite is a copper carbonate hy- Chessy, Prance. droxide, with the chemical formula CU~(CO~)~(OH)-,.Its name, in allu- sion to its color, is from the Persian word lash-ward, which means blue, Azurite is soft, with a Mohs hardness of 3 '17. to 4. Its specific gravity normally ranges from 3.77 to 3.89, although some porous material may be as low as 3.30. The refractive indices for azurite are 1.730 and 1.836, and it is biaxial positive. Fac- eted azurite is extremely rare; it is generally excessively dark, almost black, even in small gemstones. Azurite is widely associated with copper ores. Major sources of azurite in the United States are the copper- mining districts at Bisbee and Mo- renci, in Arizona; it also occurs at several localities in Nevada, New Mexico, Utah, and California. Other notable deposits include Tsumeb, Namibia; Chessy, France; and Mo- rocco, China, Mexico, Australia, the Soviet Union, Romania, and Zaire. Azurite crystallizes in the mono-

Editor's Note: The initials at the end of each item identity the contributing editor who provided that item. Gems & Gemology, Vol. 26, No. 4, pp. 294-299 @ 1991 Gemological Institute 01 America

294 Gem Trade Lab Notes GEMS & GEMOLOGY Winter 1990 strong dispersion of CZ (0.60) is no- ticeably greater than that of diamond (0.44);because the cubic zirconia and diamond were in relatively close proximity in this ring, the difference in dispersion was readily apparent. DH

DIAMOND Fancy Intense Yellow Ever since the laboratory first en- countered a Sumitomo synthetic yel- low diamond in the course of routine testing four years ago, we have rou- tinely tested all intense yellow dia- monds with both long- and short- wave U.V. radiation. Readers may recall that Sumitomo synthetic yel- low diamonds do not fluoresce to long-wave U.V, but do fluoresce a chalky greenish yellow to short-wave U.V. (see Shigley et al., "The Gem- ological Properties of the Sumitomo Figure Sf. This section of a 22-cm-long azurite specimen reportedly Gem-Quality Yellow Synthetic Dia- from Bisbee, Arizona, shows the rosettes of deep blue crystals (the monds," Gems d Gemology, Winter largest cluster measures 1.9 cm) that are common from this lo- 1986, pp. 192-208). In addition, be- cality Hare, they emerge from a bed of iron-stained malachite, cause they are type Ib diamonds, they which often occurs in association with azurite. do not exhibit any absorption lines in the hand-held spectroscope, which are present in many type la's. CUBIC ZIRCONIA not contain a 415-nn~absorption Thus far, with the exception of line, the yellow CZ in this ring did the 0.80-ct round-brilliant-cut stone Simulating a display two prominent absorption referred to in the above article, all the Fancy Yellow Diamond bands in the same area as the 453-nm faceted Sumitomo synthetic dia- Yellow cubic zirconia can effectively and 478-nm bands. This confirms the monds we have seen have been small imitate a fancy yellow diamond. need for caution when examining (less than 0.25-0.30 ct) square step Some years ago, a large yellow cubic diamond-like materials in this color cuts, having been fashioned from the zirconia, fashioned to look like a 10- range. squarish tablets prepared and sold by ct cushion octagon modified bril- Other tests helped prove the iden- Sunlitorno for use as heat sinks for liant, was submitted to the East tity of the imposter. The girdle of the electronic applications. Although we Coast laboratory (see Gems el Gem- CZ showed the typical attempt to would be surprised at this time to ology, Winter 1985, p. 234). Recently, simulate the bruted girdle of a dia- encounter any other shape, we do the East Coast lab was asked to mond, but it did not approach the test all small intense yellow dia- examine the two side stones in a frosted appearance of diamond. The n~onds,regardless of shape. While lady's ring; one proved to be a natu- orange fluorescence to long-wave writing this note, we learned that ral-color yellow diamond, but the U.V. radiation is typical of cubic zir- Sumitomo has manufactured a few other was a cubic zirconia. conia, although it has also been seen gem-quality synthetic yellow dia- Spectroscopy is the most useful in some natural-color yellow dia- mond crystals in excess of 9 ct (1. test for determining the origin of monds. Because the thermal conduc- Shigley, pers. comm., 1990).However, color in a diamond. A Beck hand-held tivity of CZ is lower than that of the firm still maintains that it has no type of spectroscope revealed the diamond, the reaction to the needle plans to market crystals to the Cape series of bands-at 415, 453, on the thermal conductivity tester jewelry industry. 466, and 478 nm-present in the was minimal. In addition, this stone Recently, the East Coast labora- natural-color type la yellow dia- had a chipped culet with an appear- tory received for examination a mond. Although cubic zirconia does ance atypical of diamond. Last, the brooch (figure 3) that contained a

Gem Trade Lab Notes GEMS & GEMOLOGY Winter 1990 which followed the periphery of the stone (figure 61, actually extended in a definite plane from the crown area into the pavilion, toward the culet. The stone did not fluoresce to either long- or short-wave U.V radia- tion. The absorption spectrum, as observed with a GIA GEM hand-held type of spectroscope unit, showed I weak Cape lines at room tempera- Figure 4. The similarity in ap- ture. When the stone was cooled with peaiance between a Sumiiomo a refrigerant, an additional faint, but synthetic yellow diamond distinct, line at 592 nm became visi- (here, the 0.19-ct stone in the ble. KH center) and the natural fancy Figure 3. Two of the fancy yel- yellow diamonds in the brooch low diamonds in this brooch shown in figure 3 is striking. of 0.5-1.0 ct stones fluoresced The sione at the lower left is to short-wave, but not to long- one of the two that fluoresced V. wave, U. to short-wave U.V. radiation. number of fancy yellow marquise- West Coast labora-tory, which and pear-shaped brilliants. We were showed a color concentration around surprised to observe that two of the the culet with magnification (figure marquise shapes (each approx- 5). This "umbrella effect" is charac- Figure 6. Oblique lighting re- imately half a carat)did not fluoresce teristic of cyclotron bombardment. vealed an additional color to long-wave, but did fluoresce green- Usually, this type of treatment does zone around the girdle of the ish yellow to short-wave, U.V radia- not penetrate very deep into the stone in figure 5; such a zone tion. Because of the settings, we stone, as evidenced by the restricted had not been observed before could not determine if these stones color concentration in the area of in a cylcotron-treated dia- had the color zoning that is some- bombardment. However, this partic- mond. Magnified 15 x . times visible in the Sumiton10 syn- ular treated green diamond differed thetic diamonds. However, infrared from others that we had seen before, spectroscopy established that these in that another zone of darker color PEARLS two stones were not pure type Ib concentration became visible when diamonds, as all gem-quality syn- oblique lighting was used. This zone, Dyed Black Cultured, thetic yellow diamonds encountered Origin of Color to date have been. They were a mix- The GIA Gem Trade Laboratory rou- ture of types Ib and la, a strong tinely examines gray to black cul- indication of natural origin. Figure 4 tured pearls to establish whether or shows a magnified view of a section not their color is natural. Proof of of the brooch with a 0.19-ct Sum- natural color, as in those black cul- itomo synthetic diamond placed in tured pearlsgrown in the area around the center for comparison. The stone Tahiti, lies in the reaction to long- at the lower left is one of the two that wave U.V radiation. Like the Pinc- fluoresced to short-wave U.V RC tada margoritifera shell in which they are grown, natural-color Tahi- Treated Green tian cultured pearls appear brownish In recent months, the laboratories on to brownish red when exposed to both coasts have received increasing long-wave U.V in a dark room. On numbers of fancy-color diamonds for the other hand, all dyed black cul- examination, many over 5 ct. Some Figure 5. The distinct zone of tured pearls seen to date, whether of these diamonds had obviously color around the culet of this treated with silver nitrate or by an- been treated to enhance their color. green diamond indicates cyclo- other unidentified dye process, either This was the case with a half-carat tron treatment. Magnified do not fluoresce at all or fluoresce a darkgreen round brilliant seen in the 15 X. dull green,

296 Gem Trade Lab Notes GEMS & GEMOLOGY Winter 1990 X-radiography may also provide Although we were unable to re- useful information. Typically, the tain these cultured pearls long layer of conchiolin in a cultured pearl enough to analyze the coloring agent, provides marked contrast between similar pearls examined by X-ray the shell bead center and the overly- fluorescence in the GIA Research ing nacre in an X-radiograph. In a Department were found to contain, cultured pearl treated with silver surprisingly, the metallic element nitrate, however, silver tends to con- tellurium. RC centrate in the area of the conchiolin; because silver is opaque to X-rays, Uncommon Cultured the X-radiograph of a cultured pearl The East Coast laboratory was asked treated with silver nitrate may show to identify the beads in the earrings a light ring around the nucleus, or it shown in figure 10. All proved to be may show almost no contrast be- cultured pearls. The button cultured tween the nucleus and the nacre. pearls are unusual in that they have During the past year, we have lentil-shaped nuclei. In addition, the encountered a number of gray to single black cultured pearl showed a black and brown cultured pearls that reversal pattern (a ring that is clients have submitted as "Tahiti" opaque, rather than transparent) in pearls. Figure 7 shows one of three the X-radiograph, which is probably - such undrilled 10-mm cultured due to the use of silver salts. Figure 10. The button-shaped cultured pearls in these ear- rings contain unusual leniil- shaped nuclei. The single black cultured pearl was found to be dyed.

Lentil-shaped nuclei are uncom- mon; we have mentioned them only once before in Gems el Gemology I I (Summer 1984, p. 109).At that time, Figure 8. As revealed in this we learned that off-round nuclei are X-radiograph, one of the dyed seldom used in the culturing process Figure 7. This 10-mm dyed because they greatly increase the black cultured pearl fluoresced black cultured pearls has a very thin deposition of nacre, mortality rate of saltwater mollusks. yellow to long wave U,V radia- Incidentally, the near-colorless bril- t ion. but the other two show strong contrast between the nacre liants in these earrings are zircons. RC pearls that were recently seen in the and the nuclei. East Coast laboratory. Unlike natu- ral-color Tahitian pearls, these three Unheated RUBY fluoresced a distinct yellow to long- Figure 9. A fingerprint pattern with a Glass Filling wave U,V radiation. The X-radio- (of dye!) was observed on the We often associate the presence of graph (figure 8) shows that two of surface of two of the three glass fillings in rubies with heat these beads have good contrast be- dyed black cultured pearls. treatment, since glass is sometimes tween the nucleus and the nacre, Magnified 60 x , used to fill the spa11 cavities that may while the third specimen has a very occur on the surface of a stone during thin nacre. With magnification, as heating. seen in figure 9, we observed a dark Recently, we observed a glass- fingerprint pattern on the surfaces of filled cavity in a 1.12-ct ruby submit- two of the beads that was unlike ted to the East Coast laboratory (fig- anything we had seen before. What- ure 11). The presence of numerous ever dyeing method was used does crystals and pristine needles, with- not require that the pearls be drilled, out surrounding stress cracks or and the color may be confined to a other evidence of heating, strongly relatively thin surface stain. indicates that the stone had not been

Gem Trade Lab Notes GEMS & GEMOLOGY Winter 1990 297 hand-held type of spectroscope, all four showed the absorption spectrum typical of natural and synthetic ruby. Three of the four contained fine in- tersecting needles, along with undis- tul-bed subhedral crystals, which proved that these three stones were natural in both origin and color. However, close examination of the fourth cabochon, second from the Figure 13. The synthetic ruby Figure 11. A glass-filled cavity left in the pin, revealed curved striae is readily apparent in this in the pin shown in figure 12 and gas bubbles. When we viewed has a glass-filled cavity. Mag- 1.12-ct faceted ruby, which this cabochon through the back, we nified 15 X. showed no other evidence of noted that the bubbles were confined heat treatment. Magnified to a shallow cavity that had been 15 x. filled with a glass-like material (fig- ure 13).The curved striae are typical of a flame-fusion synthetic. heat treated to improve color or clar- On the basis of our ongoing en- ity. However, since some glasses melt counters with filled rubies, we rec- at a low temperature, one such glass ommend that our readers not only could have been easily applied to this continue to use the techniques out- stone without producing any indica- lined in the article "Natural Rubies tions of heat treatment in the stone with Glass Filled Cavities," by itself. Robert E. Kane (Gems &> Gemology, The glass filling fluoresced a Winter 1984, p. 1871, but that they chalky yellow to long-wave U.V radi- also be on the lookout for synthetics ation and contained a large gas bub- with this type of treatment. ble. DH Figure 14. Natural-appearing Tom Moses needle-like incl~isionscan be seen against a background of SYNTHETIC RUBY, curved growth lines in this with a Glass Filling flame-fusion synthetic sap- SYNTHETIC SAPPHIRE phire. Magnified 30 x . Figure 12 shows what appears to be a modern bar pin, but with an Art Flame Fusion, with Deco design influence, that contains Needle-Like Inclusions four well-matched red cabochons The East Coast laboratory recently flame-fusion synthetic sapphire that (each approximately 8.50 x 7.00 x had the opportunity to examine a contained some needle-like inclu- 4.90 mm). When examined with a 1.77-ct cushion antique mixed-cut sions. Although these inclusions were very "natural" looking, the Figure 12. The cabochon that is second from the left in this bar pin presence of curved growth lines, also was found to be synthetic ruby; the other three stones all proved visible in figure 14, left no doubt that to be natural ruby. the stone was synthetic. On previous occasions, the lab has observed natu- ral-appearing inclusions in synthetic ruby and synthetic blue sapphire (see Gems &> Gemology, Spring 1989, p. 38, and Summer 1984, p. 111, respec- tively J. When the stone was viewed in certain directions, the needle-like in- clusions were more prominent than the curved striae and gas bubbles. As seen with higher magnification in figure 15, the needle-like inclusions

298 Gem Trade Lab Notes GEMS & GEMOLOGY Winter 1990 it would appear that some things never change. The East Coast labora- tory recently received a large piece of light, slightly greenish blue material for identification. Although the color was suggestive of turquoise, the R.I. of 1.56, hardness between 2 and 3, and S.G. of less than 2.57 elin~inated natural turquoise as a possibility. The surface of this material was smooth, and magnification revealed a molded appearance on one corner. Figure 15. Higher magnifica- With the permission of the client, tion (63 x ) reveals that the we broke off several millimeter-size "needles" in figure 14 actu- are Figure 16. The use of a translu- chips for closer examination. The ally strings of tiny gas bubbles. cent, medium dark blue plas- effervescent reaction when one chip tic filter over transmitted illu- was placed in dilute hydrochloric mination accentuates the acid indicated that the material was, are actually strings of tiny gas bub- curved color banding in this bles. The inclusions seen in this or at least contained, a carbonate. 5.16-ct yellowish orange syn- However, the chip did not completely stone are an uncommon mix for a thetic sapphire. Magnified 10 x . synthetic sapphire, which is usually dissolve. After about 15 minutes the an "easy" identification. This should reaction ceased, leaving a rough, serve as a reminder that no identi- diffused illunlination and is exam- whitish surface quite different from fication should be taken lightly. ined in different directions. Curved the original. The whitish material ft -- Nicholas DelRe yellow to orange color banding fre- that remained after the acid bath was quently becomes visible (figure 16) easily scraped. These scrapings not Orange or Yellow with this combination of color con- only looked like plastic (figure 171, trast and diffused lighting. Curved but when touched with a hot point Historically, the distinction of natu- color banding is often more apparent they also gave off an odor characteris- ral from synthetic orange ("pad- in synthetic yellow and synthetic tic of plastic. The smooth surface paradscha"] and synthetic yellow orange sapphires with the blue filter below the scraped area reacted again sapphire has been the most difficult technique than it would be without to hydrochloric acid. of the sapphire separations. Some it. R I< The infrared spectrum taken on stones contain virtually no identify- another chip yielded a curve that was ing inclusions, and curved striae may indicative of calcite, thus confirming not be readily visible in synthetic the carbonate identification. Al- sapphire in this color range (R.T. Imitation TURQUOISE though I.R. spectroscopy is often Liddicoat, Jr., Handbook of Gem The following report was reminis- useful for identifying plastic treat- Identification, 1977). Even today, cent of one in the Winter 1965 issue; ment, the diagnostic plastic peaks there are synthetic yellow and syn- fall at the same energies as broad thetic orange sapphires that prove peaks in the spectrum of calcite. difficult to identify. For these deter- Figure 17. Magnification (at Thus, the calcite spectrum of this minations, we are now using a blue 45 x) of the scraped surface of piece hid any infrared evidence of filter with the nlicroscope in a tech- the acid-treated chip of imita- plastic treatment. Ilene Reinitz nique that was initially reported by tion turquoise revealed curls B. W. Anderson and was later de- of the plastic binder. scribed by R. Hughes in an ICA Lab Because of space constraints, we Alert and a brief Journal of Gemmol- could not publish the Historical ogy article (Vol. 21, No. 1, 1988, pp. Note feature in this issue. 23-25). This technique involves placing a FIGURE CREDITS translucent, medium dark blue plas- Figures 1 and 2 are by Shane F. McClure. tic filter (just under 3 mm thick) over Nicholas DeIRe supplied figures 3, 4, and darkfield or transmitted illumina- 10-15. Figures 5 and 6 are by John I. Koivula. Dave Hargett is responsible for tion. The stone is then positioned in a figures 7, 9, and 17. Figure 8 is by Tom stone holder over the blue-filtered, Moses. Figure 16 is by Robert E. Kane.

Gem Trade Lab Notes GEMS & GEMOLOGY Winter 1990 299 GEM 1TOWS John I. Koivula and Robert C. Kammerling, Editors

DIAMONDS this was part of such an exercise." De Beers continues to emphasize that crystals of this nature are produced only De Beers announces world's largest synthetic diamond in the course of experimentation and strictly for indus- crystal. Scientists at the De Beers Diamond Research trial purposes. Laboratory (DRL) in Johannesburg, South Africa, have Previous largest synthetics have also been products successfully synthesized a 14.2-ct good-quality indus- of De Beers Industrial Diamond Division technology. In trial monocrystal diamond (figure 1).This is believed to the early 1970s, a 6.75-ct synthetic diamond was manu- be the largest synthetic diamond yet manufactured. factured; and in 1987, an 11.14-ct stone was produced Over 500 hours of high-temperature, high-pressure run- (illustrated on page 191 of the Winter 1987 issue of ning was required to produce the diamond, which called Gems &> Gemology). for prolonged maintenance of the delicately balanced In addition to Dr. Caveney, members of the DRL conditions necessary for successful synthesis. This syn- research team that successfully synthesized this dia- thetic crystal is considerably larger than the normal mond include: Moosa Adia, assistant director of re- industrial monocrystals, which are laser sliced into search; Robbie Burns, head of large monocrystal devel- components for high-tech diamond tools such as high- opment; and Vesna Cvetkovic, Carlton Dodge, Lorraine pressure anvils, scalpel blades, heat sinks, and radiation Donates, and Dennis Welch. counters. According to Dr. Robert Caveney, director of re- search at DRL, "Synthesizing a stone of this size is China-cut diamonds sold in Singapore. Diamonds cut in extremely expensive and would not in the normal course factories in Shanghai were sold at the first Shanghai be commercially viable. However, it is necessary to Diamond &Jewelry Trade Fair, held August 16-18, 1990, experiment and test our technology and equipment, to in Singapore. A total of 646 ct of the 1,400 ct offered sold continually push the boundaries further outward, and at the fair. Individual stones ranged from 0.03 to 3.0 ct; 596 ct ranged from 0.20 to 0.50 ct, while about 50 ct were over 1 ct. The stones were described as being of good make, F to K color, and WSto VS clarity, [jewelleryNews Figure 1. This 14.2-ct good-quality industrial Asia, September 1990) monocrystal synthetic diamond is reported to be the largest synthetic diamond yet manufac- Guyana mining development. An agreement has been tured. Photo courtesy of De Beers Industrial reached whereby Ivanhoe Capital Corp. can acquire a Diamond Division (Pty) Ltd. 65% interest in Golden Star Resources' Mazaruni al- luvial diamond properties in Guyana, South America. According to the agreement, lvanhoe will provide up to $C4 million in funding for exploration and development. The three properties are located in the Kurupung- Enachu region about 200 km southwest of Georgetown. [Mining lournal, September 7, 19901

COLORED STONES Possible foreign participation in Afghan mining. Af- ghanistan is well known as an important source of a number of gem materials, notably lapis lazuli, tour- maline, kunzite, and emerald. A recent report indicates that vast gold reserves have been discovered in that country as well: Deposits estimated to contain 20 tons of gold have been uncovered by Soviet geologists along the northeastern border of Badalzhshan, with an addi- tional 15 tons identified in the region's Samthi area.

300 Gem News GEMS & GEMOLOGY Winter 1990 In an effort to raise funds for mining projects, the Afghan government is expected to amend its constitu- tion to permit foreign investment in mineral resources. While the primary goal may be to develop a gold-mining industry, the proposed legislation could also open up the country to more extensive gemstone mining. (Diamond Intelligence Briefs, August 1, 1990)

Novel assembled stone. Some unusual assembled stones have been manufactured to exhibit or enhance optical phenomena. These include cat's-eye opal triplets and "star" stones produced by cementing a thin metal plate etched with three sets of intersecting lines to the base of a synthetic corundun~cabochon. Nanette Forrester of American Lapidary Artists, Los Angeles, showed us what could be described as a new "high-tech" type of assembled stone: quartz cabochons backed by computer chips. When these stones were illuminated from above, some exhibited fairly distinct four-rayed stars as well as subtle interference colors (figure 2). Ms. Forrester subsequently donated two of these unusual composites to GIA for further examination, Magnification revealed that the asterism was caused by reflection^ of light from the tightly spaced microcircui- Figure 3. This craftsman in San Miguel de try of the computer chip, which formed complex pat- Cozumel uses a lathe-driven cotton buff to pol- terns that intersect at 90'. The tight spacing also ish a piece of Caribbean black coral. Photo by produced a diffraction-grating effect, resulting in the Robert C. Kammerling. interference colors. Denton J. Anderson of Gemological Services, Denver, Colorado, created and produces these novel "gems." He Black coral industrv on the Mexican Caribbean. Coral is told us that the computer chips are cut from silicon disks an organic material that has long been used for ornamen- that are 10 cm I4 in.) in diameter and about 1.2 mm tal purposes. Black conchiolin coral is less commonly thick. They are then topped with a cabochon of hardened seen than the calcareous varieties: the best-known glass or quartz (attached with an epoxy resin). Finally, a source is Hawaii, but it has also been found elsewhere in gold paint-like substance is applied to the back. the Pacific Ocean as well as in the Indian Ocean and the Persian Gulf. The types of black coral found in Hawaii belong to the conchiolin species Antipathes dichotoma Figure 2. These novel assembled stones have and Antipathes grandis. been constructed from silicon chips and quartz. On a visit to the Mexican Caribbean during the Photo by Robert Weldon. summer of 1990, one of the Gem News editors observed the black coral industrv centered on the island of Cozumel. Essentially a cottage industry, nu- merous "black coral factories" (many no more than small gift shops catering to the tourist trade) were noted on the island as well as in towns along the adjacent mainland coast. The Mercado de Artesanias "Gonzaloz," in the town of San Miguel de Cozumel, was typical of one of these small "factories." The facility consisted of three individ- uals working at outdoor benches in front of a small shop where the finished products were sold. First, a hand-held jeweler's saw was used to cut off the desired length- of coral for fashioning. The piece was then shaped on a small grinding wheel, and the surfaces were smoothed with coarse-grit emery paper. The pieces were polished on a lathe-driven cotton buff with what appeared to be

Gem News GEMS & GEMOLOGY Winter 1990 301 jewelers' rouge (figure 3). Small detailingand piercing Activity in this area expanded significantly in the late were done by hand using a coarse metal needle. 1980s, with the introduction of heavy excavating cquip- According to the article "The Black Coral of Cozumel" ment. A report in the April 1990 issue of JewelSiam (by N. Steinhilber, Lapidary Journal, January 198 1 ) and carried a brief interview with the provincial governor, promotional literature obtained at one of the shops, who said that the province has adequate reserves to meet noted French oceanographer Jacques Cousteau discov- "strong demand" for the next 15-20 years. He also ered the black coral at depths of 65 m (about 200 ft.) identified that there are 50 mines in the province, of while studying Palancar reef off Cozumel's southwest which about 20 are operating profitably. coast in 1960. The coral requires approximately 50 years In January 1990, one of the Gem News editors had an to grow to an average of 3 cm long and 5 mnl wide. To- opportunity to visit a large, mechanized operation of day, it is recovered primarily by divers from caves and S.A.E Mining Co. The site visited is reached by driving3 crevices at depths of 95 m. lzm north of Bo Phloi on route 3086, then traveling about Cozumel's black coral is a gorgonacean coral, 3/4 km west on an unpaved local access road. Company Gorgonia species, unlike the Hawaiian Antipathes black president Paiboon Pimpisitthavorn and other executives corals. For additional information on the various types of provided information and a tour of their facilities. black coral, see H. S. Pienaar, 'African Star Coral, A New This operation uses from 300 to 500 employees, most Precious Stylasterine Coral from the Agulhas Bank, of whom are recruited locally. At the time of the visit, South Africa," Journal of Gemmology, Vol. 17, 1981, pp. the firm had identified 72 kn12 of productive area, and 589-601. approximately 1,000 acres were being worked. Before The editor was surprised to find numerous specimens excavation begins at a particular site, cores are drilled of apparently good-quality material while exploring into the sapphire-bearing gravel layer, a secondary de- beaches on the southeast coast of Cozumel Island. The posit weathered from the surrounding basaltic moun- January 198 1 report previously cited provided a possible tains. If this layer is found to be at least 3-5 m thick, the explanation, as the author of that article had had similar area is worked; if not, it is held in reserve for possible good fortune in the same area after violent storms had future development. hit the island. It is quite possible that Hurricane Diana, A promising site is mined by first stripping the which struck Yucatan only two days earlier, had assisted overburden - typically 15 m thick- with heavy equip- in this editor's harvesting. ment. The gem-bearing gravels, called lzasa, are then transported by truck to the on-site processing plant Update on sapphire mining in Kanchanaburi. Thailand's (figure 41, where they are stockpiled to insure continued Kanchanaburi Province, located approximately 100 lzm production even during the rainy season, when flooding (60 mi.) west of Bangkok, is a well-known source of often halts mining. (Admirably, because of ecological sapphires. Small-scale commercial mining activity has concerns, excavated areas are refilled with overburden taken place continuously for over 30 years in Bo Phloi, and prepared for agricultural cultivation. Water is also which is about 40 km north of Kanchanaburi City. recycled, and no chemicals are used.)

302 Gem News GEMS & GEMOLOGY Winter 1990 Procesiing of the gravels begins by washing themwith and miners and dealers alike are more optumgtic about higli-pressure water camions to remove clay and satid the future of the emerald industry in Colombia than and then passing them through & coarse screen to they have been in years. mmw&m**-m-buw ported first to (me jig, a cone-shaped rotating grid, for Unusual color-zonedgametiAnumber of gero materials further separation, and then to another, which ¥ose the cdydisplay dmzdq. Some d &me, moh aa prhciple of graviq sepsk~onto poduce a hal~~-hi- and tri-coloied tourmaline, fliay be cut intentionally trate, The halsorting and extraction d gem materials to display and emphasize the individual colors; others, is done by hand. 3lack spinel, black pyroxene, sad red such as amethyst, with zones of colored add colorless garnet are also recovered. areas, will be cut hsucha way thgt the color@ areas A visit to the sorting rooms at the Site revealed that fife masked, producing a stone that "faces up" with most of the sapphire recovered was medium to d^rk blue, drmcolor. with some green and a. few (2%-3% of total sapphire Ganuets are usually colored uniformly. Howeror, Dr. yield) light yellow stones, The yellow material can be ByronButler of Wbrld Gems/G.S.G.,Scottable, Arizona, heat treated to produce light "lemon" yellow to bright 3~6ce&tlysent us for examination the 1.42-ct &net yellow to "cognac" orangy brown stones. Some of the shown in figure 5. This modified hexagonal step cut, sapphire rough is sold as4to dealers who visit the mine reportedly from an African locality; displayed strong site. Other material is examined by S.A.2 employees, color zoning in IQht brownish yellow and medium then heat treated and cut in-house. bro-wnish orange that was only partially masked &-up Some of the faceted stones ¥wer examined at the by the cutting. milling facility Alh* these stmwere somwllat Gemdogjcd mtimof the atme ddthe less saturated (more "grayish") than heat-treated 5ri following properties: transparent; singly refractive; Lankan sapphires, they were closer in appearance to the green with some reddish orange "flashes" through the Sri Lankan material than to the dark, mky sapphires Chelsea filter; very weak brownish red fluorescence to people have come to associate with 'Thai" sapphire. long-wave U.V radiation, with a similar but slightly The editors thank Messis. Paibo~nPimpisittha~~m, chalky reaction to short-wave U.V and no phosphores- Ampan }

Gem News GEMS & GEMOLOGY Water 1990 303 of the stone, and 1.748 on the darker portion. Careless This 2.16-ct oval double cabochon (9.79 x 7.79 x 5.12 testing could lead one to believe that the stone was mm) was mined in Jalisco, the major opal-producing doubly refractive with a 0.010 birefringence. state of Mexico. The stone was acquired from another We concluded that this was a color-zoned grossular dealer who had had it in his personal collection for garnet. It is quite possible that a greater concentration of several years, the chromophore on the darker section of the stone was The opal appears opaque and almost black when also responsible for the higher R.I. reading obtained viewed face-up in reflected light; in intense transmitted there. light, such as that provided by a fiber-optic illuminator, it appears translucent with a dark orange-brown body Heavy liquids studied in Australia. Heavy liquids con- color. The base exhibits broad areas of play-of-color in taining organic compounds have long been used in gem green, yellow, and orange, while the dome shows three identification and in mineral separation, including the chatoyant bands of color, one across the dome and the separation of diamond from sands. Concerns relating to other two near the base (the latter two are not visible in occupational health and safety, as well as the complex figure 6).The top band is red in the center and green on controls required, have limited the large-scale use of either end; both side bands are predominantly green, one heavy-liquid separation. with a slightly yellowish orange center and the other The Australian Mineral Industries Research Associa- with a blue area at one end. tion (AMIRA)is embarking on a two-year study aimed at Magnification with darkfield illumination revealed identifying relatively nontoxic heavy liquids for use in minute, short stringers of whitish particles; direct mineral separation. According to the proposal, a range of transmitted light revealed a mottled layer that was inorganic compounds - especial1y the polyanions -are vaguely reminiscent of the structure seen in tortoise to be investigated to determine their application in shell. The opal had a spot R.I. of 1.44; gave a singly producing heavy liquids as solutions in water or other refractive reaction in the polariscope; was inert to both safe solvents. (Mining Magazine, July 1990) long- and short-wave U.V radiation; appeared brownish orange through the Chelsea filter; and exhibited an Black cat's-eye opal. The Fall 1990 Gem News column absorption cutoff below 500 11111, transmitting virtually described a yellow opal that exhibited true chatoyancy nothing in the blue region. and in earlier columns we have discussed assembled The specimen also had a specificgravity of 2.02, rather cat's-eye opal triplets. Recently, Neal Dwire of Neal low for opal. This, combined with the high transparency Dwire Gemstones, Tucson, Arizona, showed us an at- and the knowledge that porous opal from Jalisco may be tractive chatoyant black opal (figure 6). treated, caused us to suspect enhancement. Near-infra- red spectroscopy, performed by Dr. Emmanuel Fritsch of the CIA Research Department, revealed no indication of either polyn~erimpregnation or carbonaceous enhance- Figure 6. This 2.16-ct black opal exhibits play- ment (such as smoke or sugar treatment). We therefore of-color in the form of chatoyant bands. Photo concluded that this was a natural cat's-eye black opal. It by Robert Weldon. is the first such stone from lalisco that either editor has seen. Opals with this type of chatoyancy have been reported from Idaho. In addition to Dr. kitsch, the editors would like to thank Sam Muhlmeister, of the GIA Research Depart- ment, and Christopher l? Smith, of the GIA Gem Trade Laboratory, for assistance in examining this stone.

Exceptionally large white opal. Steven Sodokoff, of San Francisco Diamond Exchange, recently gave the editors the opportunity to examine an exceptionally large, gem- quality opal (figure 7). The stone, a free-form cabochon, measures approximately 5-112 x 4 x 1-518 inches (14.0 x 10.2 x 4.1 cm] and weighs approximately 1 Ib. 10 ozs. All of its surfaces are polished and there are no areas of matrix. Mr. Sodokoff reports that the original rough was recovered in 1976, from the Boi Morto mine (about 3.5 km north-northwest of the town of Pedro 11) in Piauf I State, Brazil. It was cut by Scott Cooky, and is being 1I called "Galaxy." The opal is translucent with a brownish white body -- color. Face-up it displays a predominantly pinfire play-

304 Gem News GEMS & GEMOLOGY Winter 1990 of-color across its entire surface. When the stone is examined from directly overhead, approxin~ately30% of the top surface displays a predominantly orange play-of- color, while the remainder shows primarily green with lesser amounts of yellow flashes as well as some violet and red. What is even more unusual for a stone this size is the fact that the opal appears gemmy throughout: Play-of- color is also seen from the sides and base of the stone, the latter predominantly green pinfire. It is interesting to note the pronounced layering in the stone. The layers run roughly parallel to the base of the cabochon.

Color-change cobalt spinel. Efraim Katz of African Gem Cutters, Miami Beach, Florida, loaned us an interesting spinel for examination. The 16.41-ct rectangular cush- ion-shaped mixed cut (15.72 x 13.51 x 10.58 inm), appears medium dark violetish blue in fluorescent light and medium dark purple in incandescent illumination [figure 8). Gemological investigation revealed some interesting properties: R.I. of 1.714 (lower than what is typical for blue spinel); red appearance through a Chelsea filter; bright re$ transmission luminescence; moderate to strong chalky red fluorescence to long-wave U.V, none to short-wave U.V, and no phosphorescence; and, when examined through prism and diffraction-grating desk- model Spectroscopes, a diffused absorption band at Figure 7. This unusually large (14.0 x 10.2 x 454-461 nm, a faint fluorescent line at 552-554 nm, and 4.1 cm) opal shows pinfire play-of-color through- a strong fluorescent line at 686 nm. out. Photo @CIAand Tino Hanilmid, The U.V-visible absorption spectrum recorded at the

Figure 8, This 16.39-ct spinel appears medium dark violetish blue under fluorescent light (left) and medium dark purple in incandescent illumination (right). Photos 0 Tino Hammid.

Gem News GEMS & GEMOLOGY Winter 1990 305 Figure 9. This faceted and carved topaz scz~lp- ture weighs more than 35,000 ct. Photo by Robert Weldon.

GIA Research Department with a Pye-Unicam 8800 from one portion. The sculpture recently cut by Stoller spectroscope revealed features known to be due to Co2+, and Lehrer represents one of the largest fashioned which is undoubtedly the cause of the predon~inantly specimens of any gem species. violetish blue color. EDXRF analysis revealed the pres- The artists found the stone to be a real challenge, ence of minor amounts of chromium and possibly especially the large front viewing face. Said Stoller, "This vanadiunl one or both of which are probably responsible topaz played by its own rules. We could not apply the for the color change. The EDXRF analysis did not reveal same techniques that we use in cutting smaller topaz any cobalt, probably because it is present in such a low gems." Added Lehrer, "The process of cutting and polish- concentration. ing took place over a two-year period. We found that the difficulties began at the final polishing stage." Invariably, Large topaz sculpture. Gem minerals form in a number they encountered scratching when the polished surface of geologic environments. Pegmati tes -small igneous would pit and then the material from these pits would bodies representing the end phase of crystallization from drag across the face. Several polishings were required of a solidifying magma - are particularly interesting to the the large front face in particular. gemologist because of the sometimes huge, high-quality crystals that form in pockets within them. In fact, these Cat's-eye bicolored tourmaline. Bicolored tourmaline pockets in pegmatites are sometimes referred to as occurs with some frequency, the often distinct color "nature's jewel box." zones resulting from changes in the environment of the Recently we had the opportunity to examine an growing crystal. However, such changes may also be exceptionally large topaz that was fashioned from a noted as differences within the inclusion scenes in the crystal that originated in a Brazilian pegmatite. The different color zones. stone, a transparent very light blue-green sculpture that Recently, Ralph Mueller of Ralph Mueller & Associ- had been both faceted and carved, measures 24.6 x 10.6 ates, Scottsdale, Arizona, loaned us a 20.65-ct bicolored x 15.8 cm and weighs approximately 35,000 ct (figure 9). tourmaline with a sharp chatoyant band at the juncture The sculpture was fashioned by Lawrence Stoller and of the two color zones (figure 10). Examination with Glenn Lehrer, of Marin County, California. It hasproper- magnification revealed that the hollow tubular inclu- ties typical of blue-green topaz, including several eye- sions running parallel to the c-axis were confined to the visible two-phase inclusions and one eye-visible three- blue portion of the stone, stopping abruptly where the phase inclusion. pink coloration begins. Edward Swoboda, co-owner with Stoller and Lehrer of The editors thank Robert Weldon for bringing this the gem, informed us that the original rough was a 79-lb. stone to their attention. (35 kg), slightly waterworn, singly terminated crystal recovered from the Barra Vermelha area of Minas Gerais More gems from the USSR? In a move that could result more than 40 years ago. Mr. Swoboda obtained the in more gemstone production in the USSR, Wales-based crystal in the 1950s. He had the stone sawn in the 1970s Robertson Consultancy Group has entered into an and cut a 20,000+-ct gem (known as the "Princess") exclusive agreement to market Soviet mineral deposits.

306 Gem News GEMS & GEMOLOGY Winter 1990 Figure 11. Immersion and diffused illumination reveal the characteristic color concentrations along facet junctions that prove that this ring- set sapphire has been diffusion treated. Photo by Nicholas DelRe. Fisure 10. Careful orientation by the lapidary placed the chatoyant band of this 20.65-ct bi- colored tourmaline along the division of the two color zones. The inclusions that cause the Figure 12. "Rainbow" quartz is reportedly pro- band are actually confined to the blue portion duced by allowing molecules of silver/platinum of the stone. Photo by Robert Weldon. to adhere to the external surface of the quartz. This cluster weighs 17.86 grams. Photo by The firm will work with the Soviet Ministry of Geology Robert Weldon and Maha Smith. to provide foreign mining concerns with data for assess- ing project potential. Although the Soviets reportedly prefer joint ventures, it appears that there is 110 longer any legislation that would preclude 100% foreign owner- ship. Seminars, exhibitions, and field trips are being planned to help interested parties gain an understanding of Soviet operating conditions and mining laws. (Mining Journal, July 20, 1990)

ENHANCEMENTS Diffusion-treated sapphire update. The Summer 1990 issue of Gems el Gemology contained a comprehensive article on blue diffusion-treated sapphires. Although this article discusses and illustrates the identification of loose sapphires so treated, the same identification tech- niques described can also be used quite effectively in detecting mounted stones. Robert Crowningshield, of the East Coast GIA Gem Trade Laboratory, provided us with a photograph of a diffusion-treated stone mounted in a ring. As can be seen in figure 11, the combination of immersion and diffused illumination reveals the color concentrations along facet junctions that are a key identifying feature of this enhancement.

"Rainbow" quartz: A new enhancement. In the Fall 1990 Gem News column we provided an update on colorless quartz gems on which a thin film of gold had been

Gem News GEMS & GEMOLOGY Winter 1990 307 Figure 13. The base of this 2.78-ct synthetic ruby (face up) and that of this 2.53-ct synthetic blue spinel (face down) have been rough-ground to give these cabochons a more natural face-up appearance. Photo by Robert Weldon. Figure 15. The 4.07-ct cabochon of "11nori Stone" glass on the right bears a strong resem- applied. These treated stones display both the blue to blunce to some pectolite from the Dominican greenish blue transmission color of gold and surface Republic, as exemplified by the 28.59-ct speci- iridescence. men on the left. Photo by Robert Weldon. The Gem News editors recently became aware of another, similar surface treatment that is being applied quartz, leaving it essentially colorless. EDXRF analysis to colorless quartz, including single crystals, crystal of the sample, by Sam Muhlmeister of the GIA Research clusters (figure 12), and some fashioned pieces. Accord- Department, did not show the presence of platinum or ing to promotional literature provided by TransGem silver. This may be due to the fact that the applied layer is Corp. of West Bend, Wisconsin (vendor of this material as so thin that it is not detectable by this method. well as 'Aqua Aura" quartz), "Rainbow" quartz is pro- duced by "allowing molecules of silver/platinum to Figure 16. Sold as "purple onyx," this 8.87-ct adhere to the natural electric charge which surrounds purple dyed quartzite could be mistaken for the quartz crystals. The extremely thin, transparent sugilite. Photo by Robert Weldon and Maha bond breaks light into a rainbow of colors." Smith. Like 'Aqua Aura" quartz, "Rainbow" quartz exhibits moderate to strong superficial iridescence in surface- reflected light. It differs from 'Aqua Aura'" however, in that it does not alter the apparent body color of the

Figure 14. The jewelry "stones" pictured here are all glass imitations of jadeite. Photo by Ro-

308 Gem News GEMS & GEMOLOGY Winter 1990 Jade "processing." It appears to be a somewhat wide- Glass imitation jadeite. From time to time, the Gem spread practice to wax- or paraffin-coat many ornamen- News editors see interesting glass imitations. Recently, tal gem materials to improve their apparent luster. one of the editors spotted some attractive imitations of Nephrite and jadeite, the two jades, are often seen so "Imperial" jadeite [figure 141 being offered by street treated. vendors both in the Chinatown area of Los Angeles and The prevalence of this practice was brought home to in Hong Kong. the editors when glancing through a Hong Kong trade The color of the piece fashioned as a saddle-cut publication, Jewellery Review. The magazine included a hololith ring was fairly uniform and similar to that of one-page pictorial on how a jade hololith bracelet is very fine green jadeite. Another piece, a "carved" circu- produced. The first step in this eight-step process is lar disk set in an imitation gold bale for use as a cutting a slab of appropriate thickness. In step 2, the medallion, exhibited a less saturated color in a mottled center of the bracelet is drilled out with a cylindrical bit. pattern, a color distribution common in jadeite jade. In steps 3 through 6, the bracelet takes its final form Magnification revealed the gas bubbles and swirled through four grinding operations, followed by polishing striae [schlieren)typical of glass imitations in all pieces, [step7). The final step, most interestingly, is described as 'waxing;" the accompanying illustration shows a A glass imitation pectolite? Pectolite is a translucent to heavily encrusted bracelet being removed from a pot of opaque greenish blue ornamental material that often liquefied wax. [Jewellery Review Vol. 2, 1990) shows one or more fibrous radial patterns. It has been marketed under the trade name Larin~ar. "Imori Stone" is a partially devitrified glass into which SYNTHETICS AND SIMULANTS fibrous inclusions are induced to give it a fibrous Natural-appearing synthetic cabochons.- While looking appearance overall. "Imori Stone" has been produced in a through a llturmali" box of inexpensive flame-fusion number of colors, with the greenish material used to synthetics at a local gem show, one of the editors spotted imitate jade. In the course of studying "Imori Stone," we some oval cabochons that had a reduced transparency noted that it also occurs in colors that make it look quite not normally seen in flame-fusion synthetics. Two of the similar to pectolite. Figure 15 shows a cabochon of this cabochon4 were purchased for examination: a 2.78-ct glass imitation next to a cabochon of pectolite. synthetic ruby and a 2.53-ct synthetic blue spinel. Standard gemological testing confirmed the identities Dyed quartz imitation of sugilite? One of the more novel of the two specimens. Visual exan~inationand magnifi- stones we have examined recently is a semitranslucent, cation verified the cause of the reduced transparency: dark purple oval single cabochon [figure 16) that was While both synthetics were essentially inclusion-free, purchased as "purple onyx." The stone was donated to they had irregularly shaped, rough-ground frosted bases GIA by Ed Barker, whose father obtained it in New (figure 13).The cabochon cut contributed to the rather Mexico. The material is being set in Indian jewelry and natural appearance of the stones, as included material of sold in considerable quantities. lower transparency is often cut in this fashion rather Standard gemological testing identified the gem as a than faceted. quartzite. While the color appears uniform in overhead We remember hearing several years ago about a clever illun~ination,strong transmitted light reveals a dense deception being used on some nice-colored faceted Sri mass of dark purple color concentrations in fractures Lankan sapphires. These stones had had their pavilion surrounding what seem to be essentially colorless facets rough-ground to increase light scattering, giving grains. The stone appears brownish orange through a them a "velvety" appearance like that exhibited by fine Chelsea color filter and is inert to both long- and short- sapphires of Kashmir origin. They were then bezel-set wave U.V radiation. Spectroscopic examination revealed to conceal the deception and passed off as Kashmir a very weak, diffused absorption band at approximately sapphires. 491-503 nm, a prominent band at 529-572 nnl, and some extremely weak general absorption through the Thailand cutting CZ. In addition to being a major yellow-green region. A slight purple discoloration was cutting center for colored stones and an increasingly produced on an alcohol-dipped cotton swab rubbed important country for diamond cutting, Thailand is also across the stone's base; an acetone-dipped swab pro- fashioning significant amounts of cubic zirconia. In duced a similar but darker and more noticeable dis- 1989, Thailand exported 13,256 kg (66,280,000 ct] of coloration. polished CZ, according to the Thai Department of While this dyed quartzite may be marketed as "purple Business Economics. The major market was the United onyx," it could easily be mistaken visually for manga- States, which imported 4,326 kg. Both figures represent noan sugilite. Since receiving the original specimen an approxin~ately13% increase by weight over 1988. from Mr. Barker, we have seen more of this material in (Jewellery News Asia, September 1990) the trade.

Gem News GEMS & GEMOLOGY Winter 1990 309 GEMOLOGICAL ABSTRACTS

Dona M. Dirlam, Editor

REVIEW BOARD

Barton C. Curren Robert C. Kammerling Christopher P. Smith Topanga Canyon, California GIA, Santa Monica GTL, West Coast Bob E Effler Neil Letson Karen B. Stark GIA, Santa Monica New York, New York GIA, Santa Monica Emmanuel Fritsch Shane F. McClure Carol M. Stockton GIA, Santa Monica Gem Trade Lab, Inc , Santa Monica Los Angeles, California Patricia A. S. Gray Elise B. Misiorowski Rose Tozer Venice, Calilornia GIA, Santa Monica GIA, Santa Monica Mahinda Gunawardene Gary A. Roskin William R. Videto Idar-Oberstein, Germany GIA, Sanla Monica GIA, Santa Monica Karin N. Hurwit James E. Shigley Robert Weldon Gem Trade Lab, Inc.. Santa Monica GIA, Santa Monica Los Angeles, California

DIAMONDS with diamond-poor lzimberlites. They also den~onstrate Study of prospecting mineralogy of spinel group in the similarity of spinel composition between diamond- kimberlites in China. Q. Shuying, D. Chujun, and bearing lzimberlites from the Yakutia region of the Soviet G. Yuemin, Abstract, 15th General Meeting, In- Union and those in China. IES ternational Mineralogical Association, June 28-July 3, 1990, Beijing, China, pp. 89-91. COLORED STONES The authors demonstrate the use of spinel-group min- AND ORGANIC MATERIALS erals as a prospecting aid in the search for diamond- The American connection. J. Culp Zeitner, Lapidary bearing lzimberlites. By plotting the composition of Journal, Vol. 44, No. 2, May 1990, pp. 59-70. spinels on an Al-Cr-Fe (or Ti) ternary diagram, they A number of gem materials have been named for their illustrate how spinels from diamond-bearing kinl- associations with American places and people, as was berlites differ in composition from spinels associated acknowledged at the recent CFMSIAFMS National Show in California. Most of these names are variety and trade names. Ms. Zeitner provides some interesting This section is designed to provide as complete a record as practical of the recent literature on gems and gemology. Articles information on the derivation of some well-known (and are selected for abstracting solely at the discretion 01 the section not so well-known) minerals. Often they are named after editor and her reviewers, andspace limitations may require that we a person: bixbite (anearly term for red beryl), after a gem include only those articles that we feel will be of greatest interest to and mineral dealer; liddicoatite (a calcium lithium our readership. aluminum tourmaline], after Richard T. Liddicoat; Inquiries for reprints 01 articles abstracted must be addressed to kunzite, after George Frederick Kunz; n~organite,after the author or publisher of the original material, J. I? Morgan; and pumpellyite (chlorastrolite],which is The reviewer of each article is identified by his or her initials at the the state stone of Michigan, after Raphael Pumpelly of end of each abstract. Guest reviewers are identified by their full Keweenaw Names derived from localities are even more names. Opinions expressedin an abstract belong to theabstracter and in no way reflect the position of Gems & Gemology numerous: danburite, from Danbury, Connecticut; or or GIA. benitoite, after San Benito County, California. Three photos, two in color, accompany this interesting article. Q 7997 Gemological Institute of America WRV

310 Gemological Abstracts GEMS & GEMOLOGY Winter 1990 An American gem geography. D. Federman, Modern Charoitites are a rare type of rock that contain Jeweler, Vol. 89, No. 6, June 1990, pp. 61-67. 35%-95% of the mineral charoite. This rock has be- Highlighted in this article are some of the major gem come an in~portantornan~ental gem material because of deposits of the United States. Mr. Federn~anbriefly its unusual purple color and its peculiar texture. The discusses the locations and mining histories of U.S. genesis of this rock type still remains a subject of deposits of turquoise, freshwater pearls, tourmaline, controversy. The authors suggest that charoitites are of diamond, sapphire, ruby, peridot, opal, and amethyst in metasonlatic origin, that is, they result from mineral chronological order of discovery. In addition, there are formation that took place by simultaneous solution and several beautiful photographs of these American gein- deposition, and not by magma crystallization. As evi- stones used in jewelry. Also provided is a full-page map dence, the authors cite the unusual mineralogy and of North America with major gem localities in the 50 textures of these rocks, their chemical uniqueness from United States indicated. Mr. Federn~anpoints out two other magmatic rocks, the acicular or fibrous crystal additional sources of information on this subject, ac- habit of the minerals, and the framework crystal struc- knowledging that this article is intended only to intro- tures of these minerals that would allow the diffusion of duce the reader to the vast and varied occurrences and chemical constituents to bring about the metasoma- histories of American gem treasures and their role in the tisn~. IES world market. CPS Mtorolite. G. Phillips and G. Brown, Australian Gem- Examination of an interesting cultured blister pearl. R. inologist, Vol. 17, No. 5, 1990, pp. 205-207, Kammerling, J. Koivula, and R. Kane, Australian Mtorolite is the name given to a green chrome-colored Gemmologist, Vol. 17, No. 5, 1990, pp. 174-1 75. chalcedony found near Mtoroshanga, Zimbabwe. The While in China, senior author Robert Kammerling authors begin by describing the history of the deposit purchased an intriguing half shell with a large blister- and then provide the results of their examination of pearl image of the goddess Kwan Yin, Inserting objects in specimens held in the museum of the Gemmological mollusl~taproduce unusually shaped blister pearls has Association of Australia's Victorian Branch. been practiced in China for centuries. This article The specimens investigated had the following prop- concentrates on the kinds of materials that are used to erties: mottled green to white chalcedonic structure; produce these blister pearls. Although lead is the most hardness of 7; 2.56 S.G. for light green and 2.57 for dark familiar, detailed examination and observation of this green material; uneven to subconchoidal fracture; 0.004 image revealed that the material was plastic. This is the form birefringence; pink to red through the Chelsea first time that this type of insert and its methods of filter, reaction correlating to depth of body color; very detection have been reported. Accompanying the report weak milky green to long-wave U.V radiation and weak are three photographs and two X-railiographs that help milky green to short-wave; brown-red in transmitted substantiate the conclusions. RW white light; general absorption with some transmission in the green and red regions. The one internal feature Golden labradorite. J. D. Lindberg, Lapidary Journal, Vol. noted was "n~ossypatches." 44, No. 3, June 1990, pp. 20-24. The authors also review the gemological properties Mexico yields large, facetable, nonphenomenal crystals reported in the literature for this material, some of of this feldspar species. Mr. Lindberg reports that Benny which are not identical to (although they are compatible Fenn has some sizable faceting n~aterialand has cut with) the results of their testing. Additional detail is some large gems, including a 92-ct Portuguese cut provided as to the location and occurrence of the (pictured in color). One black-and-white photo shows material. With respect to the latter, they note that great "two or three pounds" of material in a double handful of similarities exist between the mode of formation of eight crystals. A basic description of the n~aterialin- mtorolite and the green chrysoprase chalcedony from cludes refractive indices (oneinadvertently omitted)and Marlborough in central Queensland. RCK specific gravity, as well as crystal habit and inclusions. The only reference to the locality of this n~aterialis the New crystallochemical and genetic data for turquoise. n~ountainousarea dividing Chihuahua and Sonora, L. K. Yakhontova, I. I. Plyusnina, T, V Soboleva, Mexico. WRV Abstract, 15th General Meeting, International Mineralogical Association, June 28-July 3, 1990, Minerals and mineral parageneses of charoitites as a Beijing, China, pp. 121-122. reflection of their genesis characteristics. K. A. Turquoise from deposits in Middle Asia and Armenia Lazebnic and L. V Nikishova, Abstract, 15th was investigated to clarify the origin of these deposits. General Meeting, International Mineralogical As- Two main stages of turquoise formation could be distin- sociation, June 28-July 3, 1990, Beijing, China, pp. guished: a hydrothermal stage where turquoise formed 60-6 1. as a vein mineral with quartz and pyrite, and a supergene

Gemological Abstracts GEMS & GEMOLOGY Winter 1990 311 stage where turquoise crystallizes from solutions during mining of the diamond deposits in the Kimberley region weathering. fEs of Western Australia. Emphasis is given to the Argyle AK1 mine, which is currently the largest producer of diamonds in the world. The extraordinary aspect of Ein ungewohnlicher Granat aus Ostafrika (An unusual these deposits is the association of diamonds with garnet froin East Africa). H. Bank and U. Henn, lamproite as the host rock, rather than lzimberlite. This Zeitschrift der Deiitschen Gemmologischen Ges- type of occurrence has prompted a revision in diamond ellschu~t,Vol. 38, No. 4, 1989, pp. 161-163. exploration methods throughout the world. A brownish orange 64.47-ct garnet from East Africa While the host rocks are different, there appear to be shows an R.1. of 1.739 and an S.G. of 3.74. On the basis of no differences in diamonds from lamproites and kim- its gemological properties, it is most likely a grossular berlites based on statistical studies of crystal size, (hessonite],but, according to the authors, it could also be morphology, color, distribution, inclusions, and surface a pyrope-almandine or a pyrope-spessartine (lln~alayall), features. Details of the characteristic features of these U.V-visible absorption spectroscopy and energy-disper- diamond crystals are presented, including a brief men- sive microprobe analysis show this garnet to be a pyrope- tion of the pink diamonds that have attracted consider- spessartine with significant almandine and grossular able attention in the gem market. /Es components, the latter contributing to the low R.I. EF Famous mineral localities: De Kalb, New York. G. W Robinson, Mineralogical Record, Vol. 21, No. 6, GEM LOCALITIES 1990, pp. 535-541. The Brazilian en~eraldsand their occurrences: Socoto, Transparent, light green crystals of gem-quality diopside Bahia. D. Schwarz, T. Eidt, and l? A. Couto, Journal from this locality have been known since the late 1800s. of Gemmology. Vol. 22, No. 3, 1990, pp. 147-163. This article describes the geology, mineralogy, and min- The Socoto emerald deposits first opened in 1983 and ing history of this famous mineral occurrence in upstate quickly became one of Brazil's major sources. Production New York. The diopside crystals are found in pockets or figures through 1986 are provided in conjunction with cavities in calcium-silicate host rocks (quartz-tremolite those of nearby Carnaiba. A discussion of regional and schist to massive diopside). The crystals themselves local geology reveals the typical nature of these emerald range up to 7 cnl across, and represent some of the best deposits: an ultran~afitebody approximately 3,650 nl crystals of this mineral species ever found. The locality long and 200 111 wide, penetrated by pegmatite veins was unworlzed for many years, but small-scale mining accompanied by inetasomatically altered zones in now produces mineral specimens for collectors on a which the emerald mineralizations occur. Accessory limited basis. Several crystals and one faceted stone are minerals include molybdenite, scheelite, powellite, phe- illustrated, /ES nakite, chron~ite,asbestos, and sulfides. Reported values for Socoto emeralds are R.l.'s of lip Famous mineral localities: Murfreesboro, Arkansas. = 1.579-1.582 and 11" = 1.587-1.590, birefringence of A. L. Kidwell, Mineralogical Record, Vol. 21, No. 6, -0.007-0.009, and density range of 2.67-2.72 glcn12. 1990, pp. 545-555. Results of microprobe analyses for 20 emeralds and a This well-illustrated article describes the geology and variety of inclusions are given (but details of the analytic mining history of the diamond-bearing deposit near conditions are not provided). Study of approximately 100 Murfreesboro, Arkansas. The occurrence of liimberlite specimens with the n~icroscoperevealed a considerable in Arkansas has been known since the mid-1800s, but it variety of mineral inclusions, including mica, talc, was not until 1906 that the first diamonds were discov- chlorite, actinolite, allanite, apatite, quartz, feldspar, ered. Since that time, this deposit has had an interesting carbonates, tourmaline, hematitelgoethite, limonite1 history involving changes in land ownership and various lepidocrocite, molybdenite, pyrite, chromite, and beryl, attempts to mine diamonds on a profitable basis. Cur- as well as growth tubes and channel-like cavities, rently, the deposit is owned by the state of Arkansas and densely included core zones, color striae and zoning, managed by the state Department of Parks and Tourism, fluid (two- and three-phase] inclusions, and fractures. which allows visitors to search for diamonds for a small Regional and geologic maps and 21 photon~icrographs daily fee within the "Crater of Diamonds" State Park. illustrate the article. CMS The diamonds are found in a micaceous peridotite, first described as a kimberlite but more recently shown to have closer chemical and mineralogic affinities to the Diamonds from Kiniberley, Western Australia. J. D. diamond-bearing lamproites of Western Australia. Grice and G. L. Boxer, Mineralogical Record, Vol. Seven peridotite bodies occur within or near the state 21, No. 6, 1990, pp. 559-564. park, although not all are known to contain diamonds. This article presents a brief review of the discovery and The diamond crystals themselves represent coin-

312 Gemological Abstracts GEMS & GEMOLOGY Winter 1990 plex forms of the isometric system, with the trisoc- mines, the author provides an update on activity at the tahedron and hexoctahedron more common than the various sites at the time of a personal visit in early 1989. octahedron and dodecahedron. Most of the crystals have The Muzo area was being worked by two n~ining curved faces and edges. Between 1972 and 1988, some con~panies:COEXMINAS and TECMINAS. The former 13,000 diamonds were found by visitors to the state park. had converted almost entirely to underground mining; Of these, 60% were classified as white (i.e., near color- the procedure is briefly described. According to the less), 21% brown, 17% yellow, and 2% other colors. government-run ECOMlNAS, all mining in the area will About 10% of these could be considered fine gem quality be underground within the next few years. The author on the basis of clarity. Nearly 40 diamonds weighing 5 ct notes that because this produces far less workable "waste or more have been reported, including a 40.25-ct crystal rock," the shift to underground mining will have a discovered in 1924 that was faceted into a 12.42-ct stone. negative effect on the giiaqueros who work the mine The article concludes with a description of present tailings. mining operations in the state park, and a note regarding Yacopi, a new mine located about 15 km south of current exploration efforts in the area by several mining Muzo, was producing large quantities of pale-colored companies. Although there are no exact production material. Poor security prevented a visit to Cosquez, records before 1972, when the property became a state while information on Penas Blancas was not available park, a knowledgeable local geologist estimated that a because the area was controlled by guerillas. Production total of approximately 400,000 diamonds have been at Chivor was erratic, with no mining at the time in the recovered. /Es Buenavista area. Activity at Cachalh was limited almost entirely to repair and clearance work. A Kenyan gemstone from the feldspar family: Further The article includes three tables of official govern- observations. C. R. Bridges, G, Craziani, and E. ment production statistics which, as the author notes, do Cubelin, Australian Getnmolog~st,Vol. 17, No. 5, not give the whole picture, since much material is 1990, pp. 177-183. smuggled out of the country. The author speculates that This article reports on a follow-up investigation of gem- most of the smuggled material is sent to the United quality feldspar recovered from a pegmatite on Kioo States. RCK Hill, Kenya, about halfway between Nairobi and Mom- basa. The feldspar occurs in association with ver- The Pharoahs' forgotten emerald mines. 0. Grubessi, C. miculite, quartz, schorl tournlaline, altered garnet, and Aurisicchio, and A. Castiglioni, Journal of Gem- kyanite. Recovery is carried out using blasting material mology, Vol. 22, No. 3, 1990, pp. 164-1 77. and simple hand tools. The emerald mines exploited by the ancient pharoahs, The gem-quality material, rangingfrom colorless to perhaps as early as 2000 B.C., were worked by the blue or green, generally occurs within large, opaque Egyptians until the 13th century AD.; later, it appears, white feldspar crystals. It has a vitreous luster; 6-6 '12 they may have been worked by the Turks. Around 1750, Mohs hardness; mean refractive indices of a = 1.531, 3 however, all activity at the mines stopped, and all = 1.535, y = 1.539, with a corresponding birefringence of records and knowledge of their location was lost. Redis- 0.008; 2V angle of 89'; S.C. of 2.63 + 0.01; very weak covered in the 19th century and periodically explored pleochroism in colorless and bluish green; inert through since then, the nlines have never again been commer- the color filter; very weak to faint whitish fluorescence cially exploited. The authors report on the information to long-wave U.V radiation and inert to short-wave U.V and samples acquired on a recent expedition by Angelo Magnification revealed some healing fissures, two-phase and Alfrcdo Castiglioni. Ancient caravan paths lead to fluid inclusions, and flakes and "parcels" of vermiculite. the Sikeit region, where remains of temples and miners' X-ray diffraction and chenlical analyses were also car- residences still exist. The nearby mountains are pock- ried out. Optical observations verified the absence of the marked with the abandoned entries and cavities of the internal reflections that produce a schiller effect in some Djebel Zabarah mine. feldspars. The authors report analytic results for an ~in- The authors conclude that the material has a bulk specified number of Zabarah emerald specimens, includ- con~positionpredominantly of albite, with anorthite ing chemical analyses, basic physical properties, unit- varying from approxin~ately5 to 11 niol.%, and that it is cell parameters, and infrared spectral features. Compari- a peristeritic plagioclase feldspar which formed at rela- son with data for emeralds from eight other localities tively low temperatures. R CK and two synthetic crystal-growing processes revealed chemical similarity to emeralds from Habachtal, Aus- New aspects of the emerald workings in Colon~bia.D. tria, with substitution of Mg for A1 in the octahedral Schwarz, Australian Gemmologist, Vol. 17, No. 5, site; unit-cell and infrared features are consistent with 1990, pp. 168-1 70. the chemical data. Since Habachtal emeralds were not Beginning with a brief history of the Colombian emerald known in ancient times, the otherwise distinctive char-

Gemological Abstracts GEMS & GEMOLOGY Winter 1990 313 acteristics of the Zabarah emeralds should be useful tallinity. Furthermore, the author points out, these archaeologically. The 12 illustrations include locality techniques can provide information on the growth photos, infrared spectra, and conlparative data graphs. conditions of a crystal, and can thus be used to distin- CMS guish natural from synthetic diamonds. 1Es Sapphirine from the Kolonne area, Sri Lanka. R. R. Current issues and problems in the chemical vapor Harding and E. G. Zoysa, Journal of Gemniology, deposition of diamond. W A. Yarbrough and R. Vol. 22, No. 3, 1990, pp. 136-140. Messier, Science, Vol. 247, 1990, pp. 688-696, This brief report provides the geologic setting for sap- Yarbrough and Messier provide a status report on the phirine occurrences in the Kolonne region of Sri Lanka, chemical vapor deposition (CVD] of synthetic dia- as well as R.I.'s, S.G.'s, birefringences, and thorough mond-in particular, synthetic diamond and dian~ond- chemical analyses of two gem-quality blue sapphirines like carbon thin films-addressing points that were not from the area. The authors point out striking sim- discussed in detail by Angus and Hayman in their 1988 ilarities between sapphirine and serendibite. The latter review paper. Because specifics of the growth mecha- occurs in the same area and, while not yet encountered nism are still largely unknown, the authors review in cut form, does provide a potential problem in identi- con~monalitiesamong the numerous variations of the fication. Apparently only X-ray diffraction or chemical CVD growth technique, analysis can provide a conclusive distinction between The Raman microprobe and X-ray diffraction anal- the two. ysis are the principal techniques used to characterize the The tabulation of properties for these two minerals coatings. Although there are still technical barriers to provides a puzzling set of R.l.'s, apparently high and low quantifying the amount of nondiamond component in values, which suggest a range of chemical compositions certain films, progress has been made in understanding for both minerals that is not discussed; a complete the nlorphology and orientation of synthetic diamond listing of all indices would have been more useful and crystals in the films. There is also interest in the less confusing. nucleation of synthetic diamond on nondiamond sub- Illustrations of sites and samples, a geologic sketch strates and the adhesion of the resulting films, but map, and tables of chemistry and properties round out considerable uncertainty remains as to the precise the rest of this admirable and thorough note. CMS n~echanisminvolved. A more fundan~entalquestion is still open, too: Why does synthetic dian~ond form Titanite crystals from the Harts Range, Central Austra- instead of graphite? A nun~berof reaction schemes have lia. D. McColl and 0. V Petersen, Mineralogical been proposed, but none fits all the experimental data Record, Vol. 21, No. 6, 1990, pp. 571-574. available. Also, why don't other carbon polymorphs Well-formed gem-quality crystals of titanite have re- form? cently been found in the Harts Range, 200 km northeast The authors conclude by discussing the in~portance of Alice Springs, in Central Australia. This area is of the prospect that from the CVD metastable growth of known as a source of several gem minerals, including synthetic diamond, we may learn how to grow other sapphirine, kornerupine, and ruby. The titanite occurs in metastable, well-crystallized materials with interesting a narrow vein of feldspar-rich rock, within occasional properties, such as cubic boron nitride. EF vugs up to 20 cm in diameter. The crystals are tabular, and each displays a number of crystallographic faces. A dark-field illuminator for gemmological microscopes. The more perfect crystals are yellowish brown and 3 to 4 'T Linton and G. Brown, Australian Gemmologist, cm long. Chemical composition and unit-cell data are Vol. 17, No. 5, 1990, pp. 171-172. also presented. IES This report by the Instrument Evaluation Committee of the Gemmological Association of Australia begins with INSTRUMENTS AND TECHNIQUES a brief summary of the virtues of using darkfield illumination in gemstone microscopy. It then proceeds Catliodoluminescence of diamonds. J. Just, Abstract, to describe and evaluate a Japanese-manufactured dark- 15th General Meeting, International Mineralogi- field illuminator designed for use with microscopes that cal Association, June 28-July 3, 1990, Beijing, do not already incorporate a similar lighting system. China, pp. 182-183. The authors found the instrument easy to assemble, The author describes the use of cathodolun~inescenceas install, and use, enabling the effective exan~inationof a technique for diamond identification. A majority of even relatively nonreflective inclusions in dark-colored diamonds exhibit some degree of cathodoluminescence, gems. Their only real criticism was that the semi-matte which can be determined with a scanning electron upper surface of the ill~iminator'smask produced some microscope. Use of this technique allows one not only to confusing reflections from the surfaces of some identify diamond, but also to assess a specimen's crys- high-R.I. gems.

314 Gemological Abstracts GEMS & GEMOLOGY Winter 1990 This abstracter feels that such a microscope acces- orate the passing of a loved one, the style blossomed into sory would certainly be a valuable tool for those gen~olo- widespread popularity during the 19th century. In 1861, gists whose microscopes do not incorporate darkfield Queen Victoria went into deep mourning after the death illun~ination.Given the current gem identification chal- of her husband, Prince Albert. For the next 25 years, only lenges provided by synthetic and enhanced gems, how- mourning jewelry was acceptable for British court dress. ever, one would be better advised to obtain a good Rings, lockets, bracelets, brooches, and earrings incor- stereoscopic binocular microscope with integral dark- porating the hair of loved ones were produced in profu- field capability, R CIZ sion; hair jewels became so popular that they were even mass produced. In fact, women were cautioned to make JEWELRY ARTS their own pieces to ensure that the hair used really did belong to their loved one. The Georges & Victoria: Jewelry as a social statement. Besides the historical aspects of hair jewelry, the A. G. Kaplan, Jewelers' Circular-Keystone, Vol. article also covers the ways that hair was prepared to be 161, No. 2, February 1990, Heritage Section, pp. worked into jewelry and early advertisements that relate 270-278. to the making of hair jewelry. Excerpted from Mr. Kaplan's next edition of The Official Six color plates show examples of hair jewels to Guide to Antique Jewelry, this article presents a basic illustrate this interesting article. Unfortunately, al- overview of the styles, n~otifs,and gems that were though two books are mentioned as having inforn~ation characteristic of jewelry from the Georgian and Victo- about how to make hair jewelry, no other bibliographic rian periods, which encompassed most of the 18th and references are provided. EBM 19th centuries. Mr. Kaplan delineates the period 1714 to 1830 as Vitreous paste gem carving. N. Tagliamonte and L. Georgian and briefly describes a few styles that were Tagliamonte, Lapidary Journal, Vol. 43, No. 12, popular during that time, including naturalistic jewels, March 1990, pp. 28-33. engraved gemstones and cameos, and the classically Stone carving is about as old as humanity itself and the derived Djrectoire style. He also mentions the develop- carving of gem materials has become an art. Carved ment of paste imitation gems and pinchbeck imitation gems are used not only for personal adornment, but also gold to satisfy the rising middle class. as a symbol of a person's power and status. The Victorian period, which spanned from Queen This excellent article tells the history of paste gem Victoria's coronation in 1837 through 1900, has been carvings with an emphasis on its roots in Aquileia, a broken into three subperiods: Early Victorian or Roman- Roman colony founded in 191 B.C. (The Romans devel- tic (1837-1860], Mid-Victorian or Grand (1860-1885), oped the use of vitreous materials for their carvings, and Late Victorian or Aesthetic (1885-1890). Sentimen- since glass was readily available, economical, and ver- tal jewelry, Gothicrevival jewels; and designs that reflect satile.) Reasons for the popular uses of glass carvings are the impact of the Great Exhibition of 1851 are referred to given, and authors Tagliamonte describe the mastery of as Early Victorian styles; archeological jewelry, massive various paste carving artists through time. Other eras gold, and mourning jewelry typify the Mid-Victorian covered are the "Dark Ages," with the beginning of the period; a lighter touch in metalwork and colored stones famous Venetian glass, and the "Golden Age," during are sketchily cited as characterizing the Late Victorian which glass was used by such notables as Cartier and period. Tiffany. Three photographs of carvings representative of While it is impossible to include everything in an various eras help the reader understand the beauty and article that is this broad in scope, the author has talent involved in the glyptic arts. RW provided a general introduction tothese periods. Thir- teen color photographs illustrate the text. EBM JEWELRY RETAILING Hair jewelry: Much more than mourning. A. London and Private right to act against false advertising strength- l? London, Jewelers' Circular-Keystone, Vol. 161, ened. R. J. Jacobs-Meadway, Jewelers' Circular- No. 2, February 1990, Heritage Section, pp. Keystone, Vol. 161, No. 3, March 1990, pp. 282-285. 184-185. The authors became fascinated with hair jewelry in The anh ham Act, which gave any person or company the 1976, when they visited a small exhibit in Bennington, right to sue for the misrepresentation of goods, has Massachusetts. This visit inspired them to research the recently been revised. These latest amendments em- history of this unusual artform. power the honest jeweler to fight back against competi- Originating in Norway, the practice of incorporating tors who consistently seek an unfair conlpetitive edge, hair into jewelry spread through Scandinavia to Ger- underkarat their goods, andlor misrepresent the quality many and eventually to France, England, and America. of their colored stones. Used primarily in memorial jewelry, made to commem- Not only does the prohibition attack misrepresenta-

Gemological Abstracts GEMS & GEMOLOGY Winter 1990 315 tions, but it also attacks statements that might mislead Inclusions noted were as follows: (1)swirling gray- or deceive. For example, if a diamond is advertised as ish "clo~~diness"or "treacle;" (2)rounded high-relief flux "the finest there is." this imolies that the stone is "D- glass remnants containing a contraction bubble; (3)low- flawless." If the stone is of lesser quality and this is not relief cavities, some with two-phase fillings; (4)plati- disclosed to the customer, the customer could sue the num platelets and "needles," (5)obvious parallel growth jeweler for not providing true top quality at the adver- banding or zonal structures; (6) white flux infilling tised price. Even though the stone might be a "fine" partially healed conchoidal fractures; and (7)multiple, stone, or the "finest" for the price, the advertisement high-relief, rounded, stretched, and distorted "bubbles," might be misleading and may injure the competitor. which are possibly ren~nantsof colorless flux glass. The Lanham Act is not considered an appropriate Interestingly, a two-phase negative crystal breaking the legal recourse for small independent businesses, though. surface of the 4.36-ct crystal mirrored the ebauchated Section 43(a)of the Lanham Act is considered to be the external faces of the host. most helpful to jewelers. It promotes fair dealing of The authors conclude from the gemological evi- competitors as well as protects consumers from decep- dence that these specin~enswere either of the self- tive trade practices. KBS nucleated variety ("Type 4") or ebauchated crystals grown on Verneuil seeds ("Type S"), and that at least some PRECIOUS METALS of the current production is grown in platinum crucibles charged with white polycrystalline flux, The report is Le fasi di lavorazione per trasforniare il lingotto in un well illustrated with color photographs and photoinicro- prezioso oggetto d'oro [The stages by which ingots graphs. RCK are transformed into precious gold articles]. V d'Anna, Joy Oro, Vol. 4, No. 1, 1990, pp. 16-19. Synthesis of diamond from graphite-carbonate systems This article briefly outlines the processes needed to under very high temperature and pressure. M. transform a gold ingot into a gold jewelry item. Ms. Akaishi, H. Kanda, and S. Yamaolca, Journal of d'Anna discusses the different stages, from alloying the Crystal Growth, 1990, Vol. 104, pp. 578-581. gold to rolling it into wire and sheets. The author Synthesis of large, single-crystal synthetic diamonds at emphasizes that for every gold item produced, even a high temperatures and pressures has been successfully mass-produced item like a chain, each step must be demonstrated using a variety of metals (Fe, Co, Ni, etc.) supervised; thus, even "industrial" manufacturing as solvent-catalysts. However, the use of nonmetallic should be considered a craft. This article is printed catalysts has also been reported in industrial patents. bilingually in Italian and English. Twelve color photo- The present study was undertaken to investigate these graphs illustrate the text. RT claims. Using a mixture of graphite and the carbonates of Li, SYNTHETICS AND SIMULANTS Na, Mg, Ca, and Sr, tiny diamond crystals were synthe- Knischka-created rubies. G. Brown and S. M. B. Kelly, sized at high pressures (7.7 GPa) and temperatures Australian Gemmologist, Vol. 17, No. 5, 1990, pp. (2150°C)These crystals, up to 20 am, were transparent 199-204. and colorless but poorly formed. The authors concluded that carbonates have a strong solvent-catalytic effect 011 This Gemmology Study Club Report begins with a the transformation of graphite to diamond. Although comprehensive review of the literature on the synthetic many scientific and technological problems remain, this rubies produced by Prof. P. 0. Knischka of Steyr, Austria. study points the way toward the possible development of It then proceeds to describe the authors' examination of growth methods capable of producing transparent, high- three specimens believed to represent post-1986 com- quality colorless synthetic diamonds without metallic mercial production: a 0.63-ct oval faceted gem, a 4.36-ct inclusions or other features indicative of a laboratory llebauchated"crystal (i.e., one with rough chiseled faces), growth environment. and a 1.20-ct crystal. Note: In a second article, the authors report success- The specimens ranged from medium, slightly pur- ful results at the same temperatures and pressures using plish pinkish red to dark purple-red or bright "firey" red. graphite-sulfate and graphite-hydroxide systems. See M. Dichroism was strong in purplish red or red (ordinary Alcaishi, H. Kanda, and S. Yamaolca (1990)High pressure ray) and orange-red (extraordinary ray]. The samples synthesis of diamond in the systems of graphite-sulfate were transparent with a vitreous luster. Refractive and graphite-hydroxide, Japanese Journal of Applied indices were 1.760-1.768, with a birefringence of 0.008. Physics, Vol. 29, No. 7, 1990, pp. LI 172-L1174. JES Through the Chelsea color filter, the samples appeared a bright fluorescent red, the same reaction produced by exposure to long-wave U.V radiation. The short-wave TREATMENT reaction was either a slightly duller red or inert. The Coloration in electron-irradiated beryl. W. F. Rink, P. F. absorption spectrum was typical of that for ruby; spe- Gielisse, and H. S. Plendl, Journal of Geminology, cific gravity was 4.0. Vol. 22, No. 1, 1990, pp. 33-37.

316 Gemological Abstracts GEMS & GEMOLOGY Winter 1990 Near-colorless beryl is often treated in order to create a ological history was fast in the making. The Moche yellow color. After irradiation with 3 MeV electrons treasures were touted as the "richest in the New World," from a Van de Graaff accelerator, two defects are created: and were compared to the treasures of T~~tanlchamunin a Maxixe-type color center that gives rise to a blue Egypt. Located along 250 miles of Peru's northern coast, component, and an O^+Fe3+ charge transfer that the Moche culture has produced the finest metalwork in provides ;i ycllow conlponcnt. The blue component the Western hemisphere. As time went on, further disappears 011 heating, but the yellow color remains. The chanters of this astonishing- tale continued to unfold. main interest of the article is in the details given The latest is written by Alva, as a sort of sequel to his regarding the irradiation procedure, since the color original article ["Discovering the World's Richest Un- centers mentioned are already well known. EF looted Tomb," National Gmgaphic, October 1988). Here, the talented photography of Nathan Benn pulls you right into this unbelievable story, as you gaze on MISCELLANEOUS images of gold burial masks, effigies with lapis lazuli Mineralogy of volcanoes. F. H. Pough, Lapidary journal, inlays, and finely crafted gold necklaces and pottery. It is Vol. 43, No. 10, January 1990, pp. 74-80. a breathtaking catalog of some of the most exciting This second in a four-part series examines differences golclwork produced in pre-Columbian times. RW among volcanoes and discusses why various minerals are associated with certain types of lava flows. The article also points out some of the cataclysn~icactivities Rocks depicted in painting and sculpture. R. V. Dietrich, that volcanoes display. Dr. Pough reminds us that these Rocks s) Minerals, Vol. 65, No. 3, 1990, pp. activities are still ongoing, and encourages us to be 224-236. careful when venturing forth on Vulcan's slopes: "On This article is an overview of artistic representation of hot lava flows, keep your trouser bottonls tucked inside rocks in painting and sculpture throughout history. The your boots; unseen cracks sometin~esblast invisible hot earliest example is the Blue Monkey fresco from Crete, B.C. gas. Y~LIWon't sink; the lava is denser than you. . . .I1 The dated approximately 1600 During the Renaissance, author kontinues to build on the modes of formation the best-known artists depicting rocks were Leonardo da under which many n~inerals,including gem materials Vinci, Giovanni Bellini, and Albrecht Durer. In the 18th such as,peridot and some garnets, are born. Dr. Pough and 19th centuries, artists who created noteworthy includes five of his own color photographs. WRV examples include Paul Cezanne, Claude Monet, Wins- low Homer, and Vincent van Gogh. During this century, we have exanlples by Rene Magritte, Salvador Dali, and The Mining Law of 1872: Reforming it will drastically Georgia O'Keeffe. change the future of American mining. S. Voyniclc, The color photographs of the paintings are espe- Rock d Gem, Vol. 20, No. 12, December 1990, pp. cially interesting. Photographs of paintings that are 26-32. referred to in this excellent article but not shown can be When first instituted May 10, 1872, the purpose of the found in the art books listed in an extensive appendix. General Mining Law was to open land development in 19 Ron Conde western states. Originally, one billion acres of federal land were available for prospecting and mining; today, 400 million acres remain due to the establishment of An Urban view of jewelry. L. Urban, lewelers' Quarterly, national parks, wildlife refuges, military and federal Vol. 28, No. 4, 1989, pp. 50-51. training areas, etc. Recently, environmentalists, min- In the quiclc-paced '80s and '90s, does the jewelry eral-royalty interests, and land-use reformers have designer have time to take a beautiful photograph of his pushed for a major overhaul of the Mining Law. Mr. or her jewelry? Urban states that "one of the most Voynick provides a detailed history of the Mining Law to disappointing things about some jewelry photography is present day, as well as related withdrawal acts; discusses the 'line it up and shoot it quick' approach." And yet, a H.R. 3866, the proposal that would supersede it; and beautiful photograph of an exquisite piece of jewelry is presents a fairly unbiased account of arguments for and always a pleasure to behold. Urban suggests that photo- against the reform act. This well-written, informative, graphic recording can be made to look pleasurable and and comprehensive article will be of interest to anyone alluring, if not by learning some photographic essentials concerned about the legal aspects of mining in the U.S. yourself, then by hiringa photographer to do the work for RT you. Even though the costs may seem prohibitive at first, a good photograph library could provide a jeweler1 designer with years of inexpensive advertising. New tomb of royal splendor. W. Alva, National Gco- The article also discusses general protocol when graphic, Vol. 177, No. 6, June 1990, pp. 2-1 1. working with a professional photographer. A sidebar at When in 1988 the news of the pre-Columbian treasures the end of the article gives tips on "What Makes a Good uncovered at Sipan, Peru, reached the world, archae- Jewelry Photograph." RW

Gemological Abstracts GEMS & GEMOLOGY Winter 1990 317 GEM TESTING, they present it to the layperson in a 10th Edition manner that is lively and well orga- By Basil W Anderson, revised by E. nized. While very little of the infor- Alan fobbins, 390 pp., illus., p~lbl.by mation will be new for the gemolo- BOOK gist, others may find the book a htterworths, London, 1990. US$49.95. useful reference guide. Although the subtitle might lead Gem Testing was first published in potential readers to think that the REVIEWS.-. - - - .- 1942, and Basil Anderson was excep- Elise B. Misiorowski and book focuses only on diamonds, the tionally well qualified to write it. He eight parts actually contain a wealth B. was a pioneer in establishing what is Loretia Loeb, Editors of information for the consumer on probably the first comn~ercialgem- many additional subjects, including testing laboratory, but, more than colored stones, jewelry history, de- that, he was an exceptionally cre- sign, appraisals, and insurance. The ative scientist. During his many already familiar with Anderson's difficult topics of grading reports and years as director of the Precious great classic, Gem Testing ap- pricing are handled in a balanced, Stone Laboratory of the London proaches identification with the instructive fashion, with the advan- Chamber of Comn~erce,he added question: "Is this a diamond? -or a tages of shopping at a reputable jew- significantly to the gem tester's arse- ruby?, or an emerald?"After 11 chap- eler clearly discussed. nal. Before Basil Anderson, the spec- ters on the properties of gemstones The diamond sections cover ev- troscope was not regarded as a gem- and the equipment available to de- erything from size and shape to the ological instrument. His long series tect or quantify them, Anderson effects of clarity and color on price. of articles on spectroscopy in the wrote 17 chapters on specifics of how They also explain the importance of Gemmologis~magazine was a clas- to identify all of the major and many cut and proportion. Unfortunately, sic, and added materially to the liter- minor gems and substitutes. His ob- some of the information may be ex- ature on gemology and to the effec- servations, accumulated over a life- cessive for the average consun1er, and tiveness of the gemologist in all time in the gem laboratory, make the inclusion of current price charts kinds of identification problems. available to everyone the experience will date the book prematurely. Not only was Basil Anderson an of an especially insightful, meticu- However, the part on colored exceptional scientist, but he was also lous, intelligent, and creative scien- stones includes notes on the more an outstanding teacher and a gifted tist. common gem materials and some of writer. Most of his writings were I commend Alan Jobbins for up- the more exotic stones seen on the highly technical in nature, but they dating a classic work very effectively, market today, and, therefore, enables were written to be easily assimilated enhancing rather than detracting in the book to be more than a one-time by most gemologists, and often they any way from the qualities that have reference. Careful, accurate explana- were written with a twinkle. From made Gem Testing a must for every tions of synthetics, simulants, mis- time to time, when using Gem Test- gemologist's-and gemmologist's - nomers, and treatments are also pre- ing, one encounters the light touch library. sented. that characterized Anderson's writ- RICHARD T LIDDICOAT The book includes a good index, ing. Chairman of the Board, GIA a bibliography, and a series of appen- Gem Testing was a beautifully Santa Monica, CA dices detailing gemological associa- written and very lucid text in Ander- tions and laboratories; many of the son's day. Alan Jobbins, editor of the ENGAGEMENT AND latter appear to be jewelry stores Journal of Gemmology and former with Certified Gemologist Appraiser curator of Gems and Minerals at the WEDDING RINGS: (CGA) or Master Gemologist Ap- Geological Museum in London, is an The Definitive praiser (MGA] titleholders on staff. excellent writer and communicator Buying Guide for Although the text of Engage- in his own right. He has added chap- People in Love ment and Wedding Rings is well ters on gemstone enhancement and By Antoinette Matlins, Antonio Bo- on the manufacture of synthetics and nanno, and Jane Crystal, 269 pp., other substitutes, and he has updated illus., publ. by Gemstone Press, the text where new developments South Woods~ock, VT, 1990. warranted. But he has not made -- changes in Anderson's text where USS14.95' *This book is available for purchase at they were not essential. The authors have distilled a great the GIA Bookstore, 1660 Stewart Street, For those few gemologists and deal of information into this book's Santa Monica, CA 90404. Telephone: students of gemology who are not large-size paperback format, and (800) 421-7250, ext. 282.

318 Book Reviews GEMS & GEMOLOGY Winter 1990 illustrated with line drawings and task. Each chapter is footnoted and Other topics covered include black-and-white photos, the color has its own bibliography, making the how to select the right setting, the section is disappointing. It consists book a very useful reference for fu- pricing of quality, and how to choose mainly of badly reprinted advertising ture scholars. Black-and-white pho- a personal jeweler. The author uses material, which is properly credited tos of the rings and gems are taken photos to explain clarity and cut but does verv little to enhance the from various angles to show impor- grades, as well as the different tests usefulness of this volunle. tant features. A very, important- note involved in identifying diamond sim- Overall, this is a book for the concerning the orientation of the ulants. Self-tests at the end of every interested consumer rather than the photographs is found on the pub- chapter prompt the reader to focus on gemologist, but, because it is both lisher's page. Several of the pieces are the significant points covered. accurate and well written, it makes also depicted in color, often n~agnif- The Diamond Ring Buying an enjoyable guide for everyone. ied to show details of the spectacular Guide is a useful boolz for the first- LISA S. ROUTLEDGE workmanship and apparent quality. time diamond purchaser, the gemolo- Instructor, Resident Gemology The only complaint that these re- gist who needs a good review on GIA, Santa Monica viewers had was that the quality of diamonds, and the retailer seeking the photographs did not meet expec- more information to give to cus- tations in relation to the other quali- tomers. ISLAMIC RINGS AND ties of the book. KAREN BABCOCK STARK GEMS -THE ZUCKER The gems, frequently inscribed COLLECTION or carved as ring stones, seals, or Edited by Derek j. Content, 551 pp., talismans, include carnelian and Le Lapis Lazuli, Son Histoire, Ses ill~~s.,publ. by Philip Wilson Pub- other chalcedonies, lapis, turquoise, Gisements, Ses Imitations (Lapis Ushers, London, 1987. US$115.00' and malachite. Regrettably, fewer Lazuli, Its History, Deposits, and 1111- than one-third of the gem pieces This massive tome covers a topic itations), by Claire do Cunha, 139 described are shown in the 14-page that hitherto seems to have been pp., illus., publ. by Le Rocher, Mon- color section, leaving these reviewers overlooked: Islamic goldwork and aco, 1989. This attractive study of feeling teased and wanting more.. gem carving from the seventh to the lapis lazuli as a gem material is the Otherwise, this book is a milestone 19th deAturies. While there have first book entirely dedicated to this work on the subject and would be a been several articles written on var- gem, It is structured into three main welconle addition to the library of ious aspects of this subject, as well as parts. In the first, Ms. da Cunha any appraiser, gem collector, or passing references in many books concentrates on ancient sources and - jewelry lover who is interested in the peripherally related to it, this seems uses of lapis lazuli. In the second subject matter. to be the first book to concentrate on part, she provides detailed descrip- this specific area. MICHAEL and PAT GRAY tions of the modern sources of lapis, Essentially, the work is a de- Graystone Enterprises an exhaustive study of the structure Venice, CA tailed description of a personal col- and chemistry, as well as an exten- lection of Islamic gems and rings sive review of identification pro- assembled by Benjamin Zucker. De- cedures, from classic gemological rek Content and Ludvik Kalus nre- OTHER BOOKS RECEIVED methods to such sophisticated tech- pared the descriptive catalogue of The Diamond Ring Buying Guide, niques as electron microprobe anal- each jewel, which makes up the body How to Spot Value and Avoid Ripoffs, ysis and Raman and cathodolu- of the boolz. The section that follows by Renee Newman, 140 pp., illus., minescence spectroscopies. The the catalogue, titled "The Craftsmen publ. by International jewelry Publi- author concludes the volume with a and Their World," analyzes the sig- cations, Los Angeles, 1989, complete list and description of the nificance of the collection in four US$12.95.' This highly informative various lapis lazuli treatments, syn- chapters. The first, Ralph Pindar- guide is intended for the first-time thetics, and imitations. Wilson's excellent historic account shopper who knows very little about Several useful experiments and of "Seals and Rings in Islan~," is evaluating diamonds or jewelry observations that have never been followed by Jack Ogden's "Islanlic craftsmanship, but it could also ap- previously published are of particu- Goldsmithing Techniques in the peal to the enthusiast craving more lar note. Although the book is writ- Early Medieval Period" and Joseph information about diamonds. The ten entirely in French, it is illus- Saden's "The Art of the Goldsmith scope of the book ranges from gen- trated by numerous informative fig- Reflected in Medieval Arabic Litera- eral facts about diamonds to more ures (e.g., color photographs, detailed ture." The fourth chapter is a gloss- technical grading terms. It also con- maps, and spectra)that will be useful ary of Medieval Judeo-Arabic gold- tains pertinent information on differ- to all gemologists. The author's thor- smithing terms by Hadassa Shy. ent cutting styles, as well as on gold oughness in describing this fascinat- Every aspect of the text is pre- and other alloys, to help the con- ing gem reflects her many years of sented in English, Arabic, and sumer make intelligent purchasing experience teaching gemology. Hebrew, undoubtedly a tremendous decisions. EMMANUEL FRITSCH

Book Reviews GEMS GEMOLOGY Winter 1990 319 Index Volume 26 Numbers 1-4, 1990

SUBJECT INDEX This index gives the first author (in parentheses) and first pqe of the article, 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 (1-114), Summer (115-176), Fall (177-246), Winter (247-324).

Book reviews Burnla (Myanmar] Amber Basic Wax Modeling, An Adventure jadeite from, compared to jadeite with mushroonl inclusion (GN]228 in Creativity [Tsuyuki] 3 18 from Guatemala (Hargett] 134 Amethyst Black Pearls of Tahiti (Lintilhac] 169 scepter, from California (GN] 159 Diamond Cutting: A Complete Guide Amethyst simulant to Diamond Processing, 3rd ed. synthetic sapphire [GTLN)94 (Watermeyer)239 Calcareous concretions Andalusite The Diamond Ring Buying Guide, in Pinctada n~argoritiferamollusks cat's-eye (GTLN)94 How to Spot Value and Avoid (GTLNI 153 Ripoffs (Ncwman)318 Apatite cameo ' Emeralds of Pakistan: Geology, greenish blue cat's-eye (GN)228 mother-of-pearl. (GN1. 100 greenish blue, from Madagascar (GN) Geinology, and Genesis (Kazn~iand Cameo sin~ulant 159 Snee, Eds.) 239 plastic (GN) 159 'Aqua Aura," see Treatment Encyclopedia of Minerals, 2nd ed. Cathodolu~ninescence Aquamarine, see Beryl (Roberts, Campbell, and Rapp Jr.] in gem identification (Fritsch)64 Aquamarine, synthetic 169 Cavity filling, see Filling hydrothermal, from USSR- Engagement and Wedding Rings: The Change-of-color phenomenon, see Color manufacture, properties, and Definitive Buying Guide for People ill change identification of (Schmetzer] 206 Love (Matlins, Bonanno, and Crystal] Chatoyancy Assembled stones 318 in andalusite (GTLN] 94 beryl triplet (GN] 100 The 4 C's Value of Diamonds (Cheng] in apatite (GN]228 "bicoIored" tournlaline doublet [GN] 239 in bicolored tourmaline (GN)300 159 Gem Identification Made Easy: in black opal (GN)300 cat's-eye opal triplet (GN) 159 A Hands-On Guide to More in iolite (GN)228 "plume" agate-and-glass doublet (GN) Confident Buying and Selling in opal (GN)228 159 (Matlins and Bonanno) 169 in tanzanite (GN)228 quartz with computer-chip backing Gem Testing, 10th cd. (Anderson, rev. Chrysoberyl (GN)300 by Jobbins)318 carved (GTLN)220 tourmaline-and-cat's-eye tourmaline Illustrated Guide to jewelry localities of the 1980s (Shigley)4 doublet (GN] 159 Appraising: Antique, Period, and Chrysoprase Asterism Modern (Miller)239 from Brazil (GN] 159 in quartz (GN] 100 Islaniic Rings and Gems-The Coating (Kammerling)32 in scapolite (GN]228 Zucker Collection (Content, Ed.] Colombia Azurite 318 emerald mining in (GN]300 from France and Arizona (GTLN] 294 The Jewelry Design Source Book Color, cause of (Bayer, Craven, Hinks, Lightbrown, in black diamond (Kammerling] 282 B Ogden, and Scarisbrick! 239 in the Dresden Green diamond (Kane] Le Lapis Lazuli, son Histoire, ses Beryl 248 dyed green [GTLN) 220 Gisements, ses Imitations [Lapis in Paraiba tourmaline (Fritsch] 189 localities of the 1980s (Shiglcy) 4 Lazuli, Its History, Deposits, and in synthetic aquamarine treatments of the 1980s (Kainmerling) Imitations] (da CLIII~I~)318 (Schmetzcr)206 32 Brazil Color change triplet (GN) 100 tourmaline from Paraiba (GN) 100, in cobalt-colored spinel (GTLN)220, see also Emerald 159, (Fritsch) 189 (GN)300

320 Annual Index GEMS & GEMOLOGY Winter 1990 Color zoning fracture filled, showing "flash effect" H in diffusion-treated sapphire (Kane] (GTLN) 94 Heat treatment .-.11.5 from Zimbabwe (GN]228 of Kashmir sapphire (Schwieger] 267 in irradiated diamond [GTLN] 220, see also Beryl of Montana sapphire (GN) 100 294 Emerald sinlulant in the 1980s [Kammerling)32 in Kashmir sapphire (Schwieger) 267 crystal from fluorite (GN]228 of Paraiba tourmaline (GN) 100, in Paraiba tourmaline (Fritsch) 189 crystal from quartz and green epoxy [Fritsch) 189 Coral resin [GN) 159 of tanzanite [GN)228 black, from Mexico [GN)300 crystal from glass [GN) 100 Coral simulant (GTLN] 153 dyed beryl [GTLN)220 Corundum 'Emeraldolite" -synthetic emerald localities of the 1980s [Shigley] 4 overgrowth on beryl (Robert)288 Inclusions see also Ruby, Sapphire Emerald, synthetic (Nassau) 50 in black diamonds (Kan~merling)282 Country of origin 'Emeraldolite," see Emerald sin~ulant identification of, using Raman determination of, in Kashmir sapphire Endangered species spectroscopy [Fritsch)64 (Schwieger) 267 ivory, coral, and tortoise shell in the in Kashmir sapphire [Schwieger) 267 question [Liddicoat) 247 1980s (Misiorowski) 76 of lazulite in quartz (GTLN] 94 Crystal n~orphology Enhancement, see Coating, Diffusion of n~ushroomin amber [GN) 228 in green grossular garnet [tsavorite) treatment, Dyeing, Filling, Heat needle-like, in flame-fusion synthetic [Kane] 142 treatment, Irradiation, Treatment sapphire (GTLN) 294 Cubic zirconia in opal (GTLN] 220 developments in the 1980s (Nassau) 50 in Paraiba tourmaline (Fritsch) 189 submitted as yellow diamond [GTLN) in synthetic aquamarine (Schmetzer] 294 206 Cuts and cutting Feldspar in treated gemstones [Kamrnerling) 32 in the 1980s (Misiorowski) 76 large orthoclase crystals from Instruments Madagascar (GN) 100 tweezers with diamond grit - see also Labradorite impregnated tips [Koivula) 149 D Filling, fracture or cavity lolite Diamond of beryl, corundum, diamond, opal, cat's-eye [GN) 100, 228 etch channels in (GTLN] 153 and tourmaline (Kammerling)32 Irradiation filling fractures in (GN] 100 of diamond, "Yehuda" treatment [GN) detection of, in black diamonds hardness research [GN] 159 100 [Kamn~erling)282 with internal etch figures (GTLN] 94 of emerald, with "flash effect" to treat gemstones in the 1980s localities of the 1980s (Shigley]4 IGTLNI 94 (Kammerling)32, (Fritsch)64 treatments in the 1980s (Kammerling) of ruby and synthetic ruby (GTLN) of diamond, may produce color zoning 32 294 [GTLN]220, 294 from Trinity County, California- Fluorescence of green diamond [Kane]248 history, source, and recovery of in black diamond (GTLN] 220, [Kopf) 212 (Kammerling) 282 with unusual fluorescence (GTLN) of dyed black cultured pearls [GTLN) 294 294 Jade, see Jadeite with unusual laser drill hole [GTLN) in yellow diamond (GTLN] 294 Jade sinlulant 220 dyed calcite and serpentine [GN)228 Diamond, colored dyed green quartzite [GN] 100 black [GTLN) 220, [Kammerling) 282 glass (GN]300 Dresden Green [Kane)248 Garnet Jadeite green, detection of treatment in color-zoned grossular [GN]300 from Guatemala-history, geology, [GTLN]220, 294 localities of the 1980s (Shigley)4 mining, properties, and comn~ercial purple [GTLN) 153 see also Grossular garnet aspects of (Hargett) 134 Diamond, cuts and cutting of [grossularite) from Japan [GN) 159 developments in the 1980s Gem localities Jewelry (Misiorowski]76 of the 1980s [Shigley) 4 of the 1980sÑgems designs, metals, risk of shattering [GTLN) 94 Gems a) Gemology and trends [Misiorowski)76 Diamond, synthetic "Challenge" results (Liddicoat) 177 period, with modern gem substitutes in 14.2-ct yellow De Beers (GN)300 Most Valuable Article award (Keller) 11 1 [GTLN] 153, 220 new technology [Nassau) 50, (Fritsch)64 Glass period, with unusual hallmarks [GTLN] 9-ct yellow Sumitomo (GTLN) 294 as emerald crystal imitation [GN) 100 153 Diffusion treatment as filling in diamond [GN) 100 Jewelry design of corundun~IKammerlineI 32 as filling in ruby and synthetic ruby in the 1980s (Misiorowski] 76 of sapphire [GN) 100, 300[~ane)115, [GTLN) 294 Jewelry designers jadeite imitation (GN]300 (GTLN)220 of the 1980s - Boucheron, Bulgari, as pectolite imitation (GN)300 ~resdenGreen diamond Carrera, Cartier, Dunay, Gate, Marina history, origin, properties, and cause of in period jewelry (GTLN] 153 B., Niessing, Picasso, Van Cleef & color of (Kane)248 radioactive "egg" [GTLN) 153 Arpel, Wakabayashi (Misiorowski)76 Durability Graining of diffusion treatment in sapphire in the Dresden Green diamond (Kane) K 248 (Kane) 115 Kashmir Dyeing Granulation in the 1980s (Misiorowski]76 sapphire from (Schwieger) 267 in the 1980s [Kammerling)32 Kunzite, see Spodumene Grossular garnet (grossularite) color zoned [GN)300 green (tsavorite]from Tanzania- Ekanite locality, properties, and crystal Labradorite

asterism in (GN) 100 morphology of [Kane] 142 sunstone from Oregon-, [GNI , 100 Emerald Guatemala Lapis lazuli from Colombia [GN)300 jadeite from [Hargett] 134 banded, from Afghanistan (GTLN] 153

Annual Index GEMS & GEMOLOGY Winter 1990 321 Laser drilling Postage stamp Spectra of diamond (GTLN)220 of emerald and gold cross from Bermuda of cobalt-doped diffusion-treated Localities, see Gem localities (GN) 159 sapphire (Kane] 115 Pseudomorph of colorless and blue areas of cryptocrystalline quartz pine cone (GN] diffusion-treated sapphire (Kane) 1 15 159 of green diamond (Kane] 248 Majorica imitation pearls, sec Pearl of Kashmir sapphire, to determine simulant treatment and country of origin Mineral fakes Q [Schwieger] 267 manufactured emerald specimens [GN] Quartz of Paraiba tourmaline [Fritsch] 189 100, 159, 228 "Aqua Aura," with gold coating to of purple diamond (GTLN] 153 Mining produce iridescent blue (GN)228 of synthetic aquamarine ISchmetzer) of emerald in Zimbabwe (GN]228 dyed to imitate sugilite (GN)300 206 and environmental concerns in the with lazulite inclusions (GTLN) 94 use of, for identification in the 1980s 1980s (Shigley)4 localities of the 1980s [~higley!4 (Fritsch) 64 of Paraiba tourmaline (GN) 159, "rainbow," with silver-platinum coating [GN)3'00 Spinel (Fritsch) 189 color change in (GTLN)220, (GN]300 of sapphire in Kanchanaburi, Thailand star, from California [GN] 100 localities of the 1980s [Shigley] 4 (GN]300 see also Amethyst gune Quartzite from Tanzania (GN) 100, (GTLN) 153 Mokiime cat's-eye IGN) 100 as metal technique in the 1980s dyed green (GN) 100 Spinel, synthetic [Misiorowski]76 cabochon with natural-looking back Mother-of-pearl cameo [GN] 100 [GN] 300 Museums and gem collections Radioactivity in glass egg (GTLN) 153 Spodumene Green Vaults, Dresden, Germany (Kane) localities of the 1980s (Shigley)4 248 Raman spectroscopy Stability Myanmar, see Burma use of, in gem identification [Fritscli] 64 Retrospective of color in diffusion-treated sapphire of the 1980s (Liddicoat and Boyajian) 1 (Kanel 115 oftreatment in fracture-filled diamond 0 Rhodochrosite simulant (GN] 100 Opal dyed calcite beads [GN] 159 sugilite simulant cat's-eye (GN)228, 300 Ruby dyed quartz (GN)300 large, from Brazil (GN)300 with glass filling (GTLN)294 Synthetic crystal growth localities of the 1980s (Shigley)4 treatments (Kan~merling)32 developments in the 1980s (Fritsch]64 with plastic-like coating [GN] 228 from Vietnam [GN] 159 Synthetic gem materials sugar-treated, with plastic-like coating see also Corundum in the 1980s (Nassau] 50 (GN)228 Ruby, synthetic treatments in the 1980s (Kan~rnerling) cabochon with natural-looking back T 32 [GN]300 with unusual inclusion [GTLN] 220 with glass filling [GTLN) 294 Taaffeite unusual specimen of (GTLN) 94 Knischka (GN]228 red (GN) 100 new, aggregate-like, from USSR (GN) Tanzania green grossularite (tsavorite) from P 100 in the 1980s (Nassau] 50 [Kane) 142 'Paraiba" apatite purplish pink spinel from [GTLN] 153 from Madagascar (GN) 159 Tanzanite Paraiba, Brazil s cat's-eye (GN)228 tourmaline from [GN] 100, [GN) 159, Sapphire heat treatment of (GN]228 (Fri tsch ] 189 from Brazil and Colombia [GN] 100 see also Zoisite Pearls diffusion-treated (GN] 100, 300, (GTLN) Thailand with evidence of repair (GTLN) 153 220 sapphire from Kanchanaburi (GN)300 freshwater, from Texas [GTLN]220 diffusion treatment of - history, Thin films Pearls, cultured procedure, identification, durability, of synthetic diamond [Fritsch]64 with colored bead nuclei (GTLN] 220 and stability [Kanel 115 Topaz compared with Majorica imitation from ~anchanaburi,Thailand (GN]300 cat's-eye (GN) 159 (Hanano) 178 from Kashmir-characterization and 'Aqua Aura," with gold coating to comparison of gray baroques from Japan heat treatment of (Schwieger] 267 produce iridescent blue (GN]228 with those from French Polynesia from Montana (GN] 100 localities of the 1980s (Shigley) 4 (GTLN)220 63.65-ct colorless (GTLN)220 35,000-ct sculpture (GN]300 dyed black [GTLN) 294 treatments in the 1980s [Kammerling) treatments in the 1980s (Kammerling) gray baroque, from Japan [GTLN] 153 32 32 with lentil-shaped nuclei (GTLN) 294 see also Corundum Tourmaline natural-color gray (GTLN) 94 Sapphire, synthetic bicolored cat's-eye (GN)300 in jewelry in the 1980s (Misiorowski]76 as amethyst sinlulant (GTLN) 94 localities of the 1980s (Shigley)4 separation of saltwater from freshwater flame-fusion, with needle-like from Paraiba, Brazil [GN] 100, 159, (Fritsch]64 inclusions (GTLN] 294 (Fritsch] 189 Pearl simulant identification of orange and yellow 20.37-ct liddicoatite (GN] 100 Majorica imitation pearl - history, (GLTN)294 Treatment production, and identification of in period jewelry [GTLN] 153 'Aqua Aura1'-gold coating on topaz and (Hanano] 178 in the 1980s [Nassau] 50 quartz, to produce iridescent blue Pectolite simulant Scapolite (GN]228 "Imori stone" glass (GN)300 brownish green star (GN)228 of gemstones in the 1980s- Peridot Scattering development and detection of from Arizona (GN] 159 in purplish pink spinel [GTLN] 153 [Kammerling]32 Play-of-color 'Smaryll," see Beryl glass-filled cavities in ruby and in rock with opal cement from Sodalite synthetic ruby (GTLN) 294 Louisiana [GN) 159 semitransparent beads IGTLN) 153 of opal (GN) 228

322 Annual Index GEMS & GEMOLOGY Winter 1990 see also Coating, Diffusion treatment, Dyeing, Filling, Heat treatment, X-radiography Zimbabwe Irradiation comparison of gray cultured pearls from emerald mining in (GN)228 Tsavorite, see Grossular garnet Japan and from French Polynesia Zircon (grossiilarite] (GTLN) 220 iridescent (GN) 100 Turquoise simulant (GTLN) 294 of cultured pearl to aid in drilling from Tanzania (GN] 100 Tweezers (GTLN) 153 Zoisite with diamond grit-impregnated tips of dyed black cultured pearls (GTLN] localities of the 1980s (Shigley)4 [Koivula) 149 294 see also Tanzanite to separate cultured pearl from Majorica imitation pearl (Hanano] 178 u X-ray fluorescence USA in freshwater pearls from Texas (GTLNI diamond from California (Kopf)212 220 use of, in gem identification (Fritsch)64 v Vietnam Y ruby from (GN) 159 Yehuda treatment, see Filling 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 26 of Gems o) 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.

B '- detection in the 1980s, 3249 (Spring] M Kammerling R.C., see Kane R.E. and Boehm E.', sce Koivula 1.1. McClure S.F., see Kammerling R.C. and Koivula ).I. Boyajian WE., see Liddicoat R.T. Kane R.E. Kan~pfA.R., see Kane R.E. Menzhausen J., see Kane R.E. Kane R.E., Kamn~erlingR.C., Koivula J.I., Mercer M.E., see Fritsch E. D Shigley J.E., Fritsch E.: The Misiorowski E.B.: Jewelry of the 1980s: identification of blue diffusion-treated Dirlam D.M., see Shigley J.E. A retrospective, 76-93 (Spring) sapphires, 115-133 (Sunlmer) Moon M., see Fritsch E. Kane R.E., Kan~pfA.R., Krupp H.: Well- Muhlmeister S.M., see Fritsch E. F formed tsavorite gem crystals from Fritsch E., Rossn~anG.R.: Tanzania, 142-148 (Summer) New technologies of the 1980s: Their Kane R.E., McClure S.F., Menzhausen J.: impact in gemology, 64-75 (Spring] The legendary Dresden Green diamond, Nassau K.: Synthetic gem materials in the Fritsch E., Shigley J.E., Rossman G.R., 248-266 (Winter) 1980s, 50-63 (Spring) Mercer M.E., Muhlmeister S.M., Moon Kane R.E., see Kamn~erlingR.C. M.: Gem-quality cuprian-elbaite Keller AS.: R tourmalines from SAo Jose da Batalha, The Gems a) Gemology most valuable Robert D., Fritsch E., Koivula J.I.: Paraiba, Brazil, 189-205 (Fall) article award, 1 11-1 12 (Spring) "Emeraldolite": A new synthetic Fritsch E., see Kane R.E., Koivula J.I., Thank you! 3 (Spring) emerald overgrowth on natural beryl, Shigley J.E., and Robert D. Koivula J.I., Boehm E., Kammerling R.C.: 288-293 (Winter) Diamond grit-impregnated tweezers: A Rossman G.R., see Fritsch E. H potentially destructive gemological tool, 149- 15 1 (Summer] Hanano J., Wildman M., Yurkiewicz P.G.. Koivula J.I., see Kanlmerling R.C., Kane Schmetzer K.: Hyclrothermally grown Majorica imitation pearls, 178-188 (Fall) R.E., Kopf R.W., and Robert D. synthetic aquamarine manufactured in Hargett D.: Jadeite of Guatemala: A Kopf R.W, Hurlbut C.S., Koivula J.I.: Novosibirsk, USSR, 206-21 1 (Fall) contemporary view, 134-141 (Summer] Recent discoveries of large diamonds in Hurlbut C.S., sec Kopf R.W. Schmetzer K., see Shigley J.E. Trinity County, California, 212-219 Schwieger R.: Diagnostic features and heat (Fall) treatment of Kashmir sapphires, J Krupp H., see Kane R.E. 267-280 (Winter) Shigley J.E., Dirlam D.M., Schmetzer K., Jobbins E.A., see Shigley J.E. Jobbins E.A.: Gem localities of the L 1980s, 4-31 (Spring) K Liddicoat R.T.: Shigley J.E., see Fritsch E. and Kane R.E. Kammerline R.C., Kane R.E., Koivula J.I., Congratulations! 177 [Fall] ~c~lure~s.~.:An investigation of a The country of origin question, 247 suite of black diamond jewelry, 282-287 (Winter) Wildman M., see Hanano J (Winter) Liddicoat R.T., Boyajian W.E.: The 1980s in Kan~merlingR.C., Koivula J.I., Kane R.E.: review: New realities of the gem and Y Gemstone enhancement and its jewelry industry, 1-2 (Spring) Y~~rkiewiczP.G., see Hanano J.

Annual Index GEMS & GEMOLOGY Winter 1990 323