FALL 1987 Volume 23 Number 3

TABLE OF CONTENTS

EDITORIAL 125 What Is a Synthetic? Richard T Liddicont FEATURE 126 An Update on Color in Gems. ARTICLES Part I: Introduction and Colors Caused by Dispersed Metal Ions Emmanuel Frjtsch and George R. Rossman The Lennix Synthetic Emerald Giorgio Graziani, Edward Giibelin, and Maurizio Martini

NOTES I 148 Synthetic or Imitation? AND NEW An Investigation of the Products of TECHNIQUES Kyocera Corporation that Show Play-of-color Karl Schmetzer and Ulrich Henn Man-Made Jewelry Malachite V. S. Balitsky, T M.Bublikova, S. L. Sorolizna, L. V. Balitskaya, and A. S. Shteinberg Inamori Synthetic Cat's-Eye Alexandrite Robert E. Kane REGULAR Gem Trade Lab Notes FEATURES Editorial Forum Gem News Book Reviews Gemological Abstracts Suggestions for Authors

------ABOUT THE COVER: Many factors contribute to color in gem materials. This issue introduces the first of a three-part series that explores and reviews the current understanding of gemstone coloration, both natural and by treatment. This first part discusses factors that govern the perception of color and then studies the role of one of the best known causes, dispersed metal ions, in the color of many gem materials. For example, the yellow color in this 65-ct untreated sapphire is primarily due to the presence of a certain content of octahedrally coordinated Fe3+ and TP+;the demantoid garnets that surround it are colored by Cr3+ in octahedral coordination. This brooch, set in platinum with diamonds, dates from the First World War. Courtesy of R. Esmerian, Inc., New York. Photo @ Harold &> Erica Van Pelt-Photographers, Los Angeles, CA. Typesetting for Gems & Gemology is by Scientific Composition, Los Angeles, CA. Color separations are by Effective Graphics, Compton, CA. Printing is by Waverly Press, Easton, MD.

@ 1987 Gemological Institute of America All rights reserved ISSN 001 6-626X EDITORIAL Editor-in-Chief Editor Editor, Gem Trade Lab Notes STAFF Richard T Liddicoat Alice S. Keller C. W Fryer Associate Editors 1660 Stewart St. Editor, Gemological Abstracts Peter C. Keller Santa Monica, CA 90404 Dona M. Dirlam D. Vincent Manson Telephone: (213)829-2991 Editor, Book Reviews john Sinkankas Editorial Assistant Elise B. Misiorowski Technical Editor Nancy K. Hays Contributing Editor and Carol M. Stockton Subscriptions Editor, Gem News Lisa Hebenstreit, Manager John 1. Koivula Diane J. Emmons, Assistant Manager

PRODUCTION Jennifer Brosious Julie Matz Cecile Miranda STAFF Linda Manion Patricia Mayer Ruth Patchick Susan Kingsbury Peter Johnston

EDITORIAL William E. Boyajian Robert C. Kammerling Sallie Morton REVIEW BOARD Santa Monica, CA Santa Monica, CA Son Jose, CA Robert Crowningshield Anthony R. Kampf Kurt Nassau New York, NY Los Angeles, CA Bernardsville, N1 Dennis Foltz Robert E. Kane Ray Page Santa Monica, CA Los Angeles, CA Santa Monica, CA Chuck Fryer John 1. Koivula George Rossman Santa Monica, CA Santa Monica, CA Pasadena, CA C. S. Hurlbut, Jr. Henry 0. A. Meyer James E. Shigley Cambridge, MA West Lafayette, IN Santo Monica, CA

SUBSCRIPTIONS Subscriptions in the U.S.A. are priced as follows: $32.95 for one year 14 issues), S89.95 for three years (12 issues) Subscriptions sent elsewhere are $42.00 for one year, $120.00 for three years. Special annual subscription rates are available for all students actively involved in a G1A program: S29.95 U.S.A., $39.00 elsewhere. Your student number must be listed at the time your subscription is entered. Single issues may be purchased for S8.50 in the U.S.A., $1 1.50 elsewhere. Discounts are given for bulk orders of 10 or more of any one issue. A limited number of back issues of G&G arc also available for purchase. Please address all inquiries regarding subscriptions and the purchase of single copies or back issues to the Subscription Manager. For subscriptions and back issues in Italy, please contact Istituto Gemmolog~coMeditcrraneo, Via Marmolaia #14, -38033, Cavalese TN, Italy. MANUSCRIPT Gems a) Gemology welcomes the submission of articles on all aspects of the field. Please see the Suggestions SUBMISSIONS for Authors in this issue of the journal, or contact the editor for a copy. Letters on articles published in Gems a) Gemology and other relevant matters are also welcome. COPYRIGHT Abstracting is permitted with credit to the source. Libraries are permitted to photocopy beyond the limits of U.S. AND REPRINT copyright law for private use of patrons. Instructors are permitted to photocopy isolated articles for noncommercial PERMISSIONS classroom use without fee. For other copying, reprint, or republication permission, please contact the Editor. Gems eJ Gemology is published quarterly by the Gemological Institute of America, a nonprofit educational organization for the jewelry industry, 1660 Stewart St., Santa Monica, CA 90404. Postmaster: Return undeliverable copies of Gems a) Gemology to 1660 Stewart St., Santa Monica, CA 90404. Any opinions expressed in signed articles are understood to be the views of the authors and not of the publishers. What Is a Synthetic? Richard T. Liddicoat, Editor-in-Chief

n recent years, there has been an ongoing debate over what constitutes a synthetic and even Iwhether the term itself is appropriate. In a letter to the editor in this issue, Dr. Eugene Love contends that the definition of synthetic as it has come to be used in gemology (i.e., to indicate the man-made equivalent of a natural gem] differs from the classic definition (i.e., that anything made by man is synthetic], and that the limited gemological definition should thus not be used. Moreover, manufacturers whose products virtually replicate the chemical composition and crystal structure of the equivalent mineral object strenuously to the term synthetic on the grounds that it has been used so often as a synonym for artificial (i.e., Dr. Love's classic use) that the public doesn't know the difference gemologically. Their objections also have merit. Yet dealers of natural gemstones have protested the use of any other term to describe manufactured gem equivalents. Marketing skills today are such that it is easy, through the subtle use of language, to convince the consumer that a laboratory product with all the properties of the natural gem is the work of nature. The term synthetic leaves no doubt. In the view of the average stone dealer, the more rigid the restraints, the better. This viewpoint, too, deserves consideration. Because these opposing positions both have merit, this whole subject is one that resists consensus in the jewelry industry. While the "limited" definition of synthetic has its drawbacks, the consumer is less likely to be misled in any costly fashion, in my view, than by other terms such as created, 'which may suggest that the design rather than the material was created by the manufacturer. "Man-made" (or "woman-made," in the case of Judith Osmer's Ramaura products) leaves little doubt, but does not clearly distinguish gem equivalents from nonequivalent simulants such as the diamond simulant cubic zirconia (whichdoes not duplicate all of the properties, and attributes, of diamond as a synthetic diamond does]. If a reasonable substitute for synthetic-one with a meaning that is unmistakable to consumer and dealer alike-were to be proposed, I would be delighted to endorse it. Until then, synthetic remains the best choice. Another part of the synthetic controversy is represented in this issue by Dr. Karl Schmetzer's eloquently stated proposition that Inamori "synthetic" opal should not be regarded as synthetic (in the strict sense) because it does not contain water, whereas all natural opals do (although the Inamori product does contain the silica spheres that are essential to the play-of-color). One might propose the same argument for excluding flux synthetic emeralds, since all natural emeralds also contain water. Of course, water is considered sufficiently essential mineralogically that H20is part of the chemical formula for opal, while it is not for emerald. Here, however, we approach the issue of just how similar a synthetic must be to the natural gem material to merit the term synthetic, gemologically speaking. There has been little objection over the years to the application of synthetic to flame-fusion synthetic spinel, which has a major compositional difference from any spinels found in nature. And yet, given that the water in natural opals can be extremely low in concentration, the Inamori product-even with no water whatsoever present - is closer in composition to many natural opals than most synthetic spinels are to their natural namesakes. To quote Dr. Kurt Nassau from a personal communication: "the feeling in the U.S.A. appears to be that the product does not need to be 'absolutely identical,' but essentially the same" to be called a synthetic. Obviously, there is need for some consensus as to how similar constitutes synthetic. At the one extreme is Dr. Schmetzer's narrow view, and at the other is Dr. Love's (to me] overly general definition. Clearly, we need definitions meaningful to consumers on which gemologists can agree.

Editorial GEMS & GEMOLOGY Fall 1987 125 AN UPDATE ON COLOR IN GEMS. PART 1: INTRODUCTION AND COLORS CAUSED BY DISPERSED METAL IONS By Emmanuel Fritsch and George R. Rossman

Studies concerning the origin of color in he origin of color in minerals in general and gem gem materials have grown in sophistica- Tminerals in particular has been investigated with tion in recent years, so that much new in- increasing sophistication in recent years. The new infor- formation is now available about natural mation provided by this research demonstrates that sev- color and its possible modification by var- eral mechanisms can contribute to the coloration of a ious treatment processes. This three-part single gem. Moreover, recent concerns about gemstone series of articles reviews our current un- derstanding of gemstone coloration. The enhancement, which usually implies color enhancement, first part summarizes the factors that gov- make it necessary to understand what happens during ern the perception of color, from the treatment and what changes in appearance can and cannot source of light to the human eye, and be achieved. then examines in detail the role of one A strong interest in minerals arose early in history, color-cozising agent, dispersed metal ions, because they are among the few natural materials that can in the coloration of many gem materials, permanently retain color, unlike flowers and plants, which including ruby and emerald. The second fade or change with time. Colorful minerals such as iron part will explore charge-transfer phenom- oxides became the basic pigments of early paintings. ena and color centers as the cause of color Eventually, colored stones were cut and polished so they in gems such as blue sapphire and Maxixe could be worn for adornment. From antiquity into the 18th beryl. The series will conclude with col- ors that can be explained usjng band century, color was also at the center of numerous supersti- theory and physical optics, such as the tions, legends, and even "medical" treatments involving play-of-color in opal and the blue sheen gems and minerals. Yellow stones, for example, were of moonstone feldspars. supposed to cure jaundice, and green stones were believed to soothe the eyes (Kunz, 1913). As mineralogy became a science at the turn of the 19th century, color was used as a common indication in the ABOUT THE AUTHORS identification of minerals. Soon, though, people discovered Dr. Fritsch is research scientist at the Gemologi- cal Institute of America, Santa Monica, California. that crystals of the same mineral species could vary in Dr. Rossman is professor of mineralogy at the color, and they began to surmise that some hues were California Institute of Technology, Pasadena, Cali- related not to the mineral but to specific impurities (figure fornia. 1).Goethe, for example, was one of the first to relate the Acknowledgments: E.F. wishes to thank Professor amethyst coloration in quartz to its iron content. The Georges Calas, of the University of Paris VII, for his support in writing the original French version simple correlation between a certain color (e.g., "emerald of this article. Special appreciation is due to Pat green") and a given element (chromium) works to some Gray for typing and correcting the "French ac- extent, but modern research has shown that a number of cent" of the original manuscript. Thanks to Laurel Bartlett, John Hummel, and James Shigley for very different processes can result in a similar color their constructive comments. (Nassau, 1983). 0 1987 Gemological Institute of America Extensive collections of mineral and gemstone spectra

126 Color in Gems, Part 1 GEMS & GEMOLOGY Fall 1987 Figure 1. A number of different mechanisms are responsible for the vari- ety of colors found in tourmaline. For example, the blue color of indi- colite is caused by dis- persed Fez+, but charge transfer between iron ions often contributes to the color of the green va- rieties. This article ex- plains the influence of dispersed metal ions in the color of many differ- ent gem materials; ihe other two articles in this series will examine other causes of color such as charge transfer. Photo 0 Harold el Erica Van Pelt.

were assembled in the Soviet Union by a variety of ing color in fluorite. Nevertheless, many terms researchers during the 1940s to 1960s. A theory persist (such as "chrome" fluorite from Muzo, developed in 1929 to explain color in crystalline Colombia) that originate from erroneous beliefs solids was first applied to mineralogy in the late about the origin of the color ("chrome" fluorite is 1950s and was widely employed to explain color in actually colored by samarium). minerals in the 1960s. In the U.S., the application In the course of modern research, five basic of the science of color to minerals experienced its mechanisms have been identified as causes of major impetus around 1970, with the publication color in gem materials: dispersed metal ions, of Mineralogical Applications of Crystal Field charge-transfer phenomena, color centers, band Theory, by Roger Burns. At approximately the theory, and physical optics. The purpose of this same time, the optical properties of various syn- series of articles is to review the current knowl- thetic colored crystals were described (e.g., Kittel, edge of the origin of color in gems (see Fritsch, 1956; Farge and Fontana, 1979; Bill and Calas, 1985, for a broader discussion of the cause of color 1978). Some long-standing and widely accepted in minerals in general), illustrating each mecha- explanations among gemologists were reevaluated nism with a number of examples and indicating according to new understanding of the origin of briefly how treatment affects each type of colora- color. For example, organic products had long been tion. First, however, it is important to understand held to be responsible for the blue coloration of the external factors that may influence our percep- fluorite, as mentioned in the 2nd edition of Web- tion of the coloration of a gem. Therefore, this ster (1970).In 1978, however, Bill and Calas dem- initial article examines the role of light and the onstrated the role of ionizing radiation in generat- human eye and then describes the best-known

Color in Gems, Part 1 GEMS & GEMOLOGY Fall 1987 127 cause of color in gem materials: dispersed metal ions.

LIGHT AND THE HUMAN EYE ULTRAVIOLET Three factors are important in establishing the color of a gemstone: the type of illumination, the stone itself, and the human eye. Depending on whether the light source is incandescent, fluores- cent, or the sun, the appearance of a gem may vary considerably. Some gem materials demonstrate a total color change from one type of illumination to another (the "alexandrite effect," as explained, for example, in Farrell and Newnham, 1965).In addi- tion, the stone itself will modify the incoming Blue light in various ways, generally by absorbing part \ VISIBLE of it and transmitting the remainder. The trans- mitted light is then received by the human eye and Green transformed into a color perception by the brain. To understand the origin of color in the object Yellow itself, we must first briefly explore the roles of the Orange light source and the human eye. Red

What Is Light? A prism will separate sunlight into ------the colors of the rainbow-a juxtaposition of INFRARED violet, blue, green, yellow, orange, and red. Each of these colors, usually designated as "spectral col- ors," represents part of the visible spectrum (figure Figure 2. Each of the colors that make up visi 2). Light of a particular wavelength carries a given ble light corresponds to a specific wavelength energy - the shorter the wavelength, the higher the and energy range. energy. The visible range extends, depending on the observer, from about 375 nm up to 740 nm. In sunlight, higher energy radiations (such as ultra- almost blaclz when observed with such illumina- violet) and lower energy radiations (such as infra- tion. As an early French author stated, "it is the red) are also present. strangest thing in the world to see a magnificent One of the mechanisms that causes color is the sapphire parure become black in the candle's absorption by a gemstone of part of the visible glimmer" (Pouget, 1752). Fluorescent light, how- wavelengths that are passing through it. Thus, if a ever, emits a much larger proportion of light at the stone absorbs mostly red and violet-blue, as is the blue end of the visible spectrum and is, therefore, a case with emerald, the light that is not absorbed more desirable source of illumination for blue (i.e., green, plus a little yellow and blue) passes stones. through the stone, which will thus appear green. As mentioned earlier, the color of some gem The Human Eye and Color. Two classes of light- materials may be strongly modified when the sensitive cells are present in the retina of the source of illumination is changed. For example, human eye: cones and rods. If the light intensity is alexandrite is green in sun (fluorescent) light and low (as in a dimly lit room), there will be no color red in incandescent (e.g., candle) light. These two sensation. Objects appear in shades of gray. This light sources contain different proportions of the phenomenon is related to the use of the rods, which spectral colors. The flame of the candle has an are responsible for vision under poor lighting and orange tint, because it is emitting much more contain only one pigment (see, e.g., Wasserman, yellow, orange, and red than blue. In fact, it is 1978). emitting so little blue light that a stone transmit- At higher levels of illumination, color percep- ting only blue, such as blue sapphire, will appear tion involves the cones. Each cone contains one of

128 Color in Gems, Part 1 GEMS & GEMOLOGY Fall 1987 of the color-causing agent. Dispersed ions are single atoms, and thus thesmallest possible cause of color. Charge-transfer phenomena and the cre- ation of color centers both require small groups of atoms. A much larger cluster of atoms is involved in band theory. Lastly, physical structures of con- siderable dimension compared to the size of the atom (lamellae, for example) are responsible for colors explained by physical optics. In the case of these large structures, the color is determined primarily by their size and shape; for a few gem materials, texture has a greater impact on color (andphenomena) than does chemical composition. We will begin this discussion of the causes of WAVELENGTH (nrn) color in gemstones by examining how color is induced in gem materials through the absorption Figure 3. As evident from this graph of the of light by dispersed metal ions. "Dispersed" here spectral sensitivity of the human eye, a person's greatest sensitivity is to the color green. means that the ions are sufficiently isolated from Adapted from Duplessis (1 985). one another by other types of atoms that they never interact. three fundamental pigments, which have a maxi- COLORS CAUSED BY mum absorption in the red, the blue, and the green, DISPERSED METAL IONS respectively. The color we perceive is a combina- How Does an Ion Absorb Light? An atom con- tion of the responses coming from the three sists of a positively charged nucleus and negatively different types of cones, which depend in turn on charged electrons, which are in motion about the their levels of reaction to a given light stimulus. nucleus. The identity of the atom is determined by The human eye is not equally sensitive to each the composition of the nucleus. When the number visible color. Rather, it is most sensitive to green, of positive charges in the nucleus is equal to the as shown in figure 3 (Duplessis et al., 1985). It is number of negative charges (electrons]around it, interesting to note that the peak of this curve the atom is neutral. When it is not electrically coincides with the peak wavelength of the solar neutral (e.g., when it has an extra electron), it is radiation at the surface of the earth. In fact, the called an ion. The actual electric charge of the ion uneven spectral sensitivity of the human eye has is referred to as the valence state, and is sym- long been viewed as an adaptation to life with bolized by a sign and a number attached to the sunlight (Nassau, 1983). symbol of the atom, such as Cr3+ for chromium with three electrons missing, or 02- for oxygen THE INTERACTION OF LIGHT with two additional electrons. Sometimes a corre- WITH GEMSTONES sponding adjective exists: Ferrous iron is Fez+ and

Many things can happen to the light entering a cut ferric iron is Fe3 + . stone: It can be reflected, refracted, diffracted, Electrons are conveniently represented as scattered, absorbed, or simply transmitted. Al- moving around the nucleus within specific vol- though absorption is by far the most important umes called orbitals (figure 4). A given number of factor in determining color, one must realize that electrons revolving in a set of orbitals represent a several combinations of these different processes certain energy for this particular ion. Absorption are possible; for example, a colorless (nonabsorb- occurs when illumination causes one electron to ing) gem may acquire color by diffraction (e.g., move from one orbital to another orbital of higher opal). We will, therefore, describe the numerous energy. The corresponding change in energy of the causes of absorption in the first two parts of this ion equals the energy of the light absorbed. This series, and then, in the last part, will consider the can be illustrated schematically in energy-level remaining possibilities that influence color. In so diagrams, such as in figure 5. doing, we will follow as well an increase in the size When an electron absorbs light it changes its

Color in Gems, Part 1 GEMS & GEMOLOGY Fall 1987 Figure 4. These are some orbitals of metal ions that cause color in gem materials. The electrons move around the nucleus within these volumes of specific shape and direction. Adapted from Fyfe (1964); reproduced with permission.

. . - . / . .. .,& . .. - ...... , ,,;.. , - .hi? . ..,:- > ,, - ,, ..

orbital. This process is called a transition, from the band (the missing wavelengths). With a spec- ground state (low-energy initial configuration of trophotometer, it appears as a broad absorption the electrons) to the excited state (a higher-energy band on the graph (again, see figure 5). configuration). Figure 5 shows how an absorption The excited state is intrinsically unstable, so band as seen with a hand-held spectroscope relates the electron must return to its normal ground both to a (more accurate) spectrum recorded on a state. Generally, there are two ways for this to spectrophotometer and to an energy diagram that happen. The more common way is for the electron indicates the various energy levels involved. When to release the energy to the crystal lattice in the the transmitted light is observed with a hand-held form of atomic vibrations (heat). The other way, spectroscope, the absorption will give rise to a dark which can be of great gemological significance, is

Figure 5. An absorption spectrum as seen in a hand-held spectroscope is compared with that obtained with a research spectrophotometer and the relevant representation of the funda- mental mechanics of light absorp- tion. When a crystal absorbs light, electrons are moved from the low energy (ground) state to a higher en- ergy (excited) state. This energy is

^-+ ultimately lost when the electron re- Inlermediak -- Luminescence - - -- turns to its ground state by dissipat- energy level ,1 (emission band) / ing the energy either as heat in the crystal or through the emission of light (luminescence).

Ground st* - - ABSORPTION - Absorption of light drives the electron Optical absorption into a higher energy state and emission spectrum

130 Color in Gems, Part 1 GEMS & GEMOLOGY Fall 1987 luminescence, in which part of the energy ac- quired in the transition is converted into light emitted by the stone. Since the electron cannot emit more energy than it absorbed, luminescence must occur with an emission of energy equal to or less than that acquired in the absorption, as can be seen in figure 5. This means that the wavelength of luminescence must be equal to or longer than that of absorption. For example, Cr3 + in ruby absorbs in the yellow-green and luminesces in the red. This is also why so many gemstones emit visible (low energy) luminescence when exposed to ultraviolet (highenergy] radiation. Absorption in the ultravio- let spectral range results in an emission at a lower energy, that is, in the visible range. Figure 6. The difference in color intensity be- tween a pink beryl (morganite)from Brazil, The Identity of the Ion Affects the Color. In colored by Mn2+,and a red beryl from Utah, actuality, very few ions have the ability to absorb colored by Mn3+, illustrates the importance of visible light. The ones most commonly encoun- the valence state of the coloring ion. Photo by Shane McCliire. tered in gemstones are the ions of the following elements: titanium (Ti),vanadium (V),chromium (Cr),manganese (Mn],iron (Fe),cobalt (Co],nickel (Ni),and copper (Cu].Although a number of other this material contains Mn3+ rather than MI$+. elementscan also cause color, such as cerium in The reason for such differences has to do with the some orange cubic zirconia and uranium in heat- probability of occurrence of certain transitions, treated blue zircon, they tend to be restricted to and is explained by certain rules of quantum only one'material. mechanics, which are beyond the scope of this In most cases, different metal ions produce article. Because Mn^ (and Fe3+)transitions have different colors. For example, in general, colors a low probability of occurrence, they give rise to produced by iron will be quite different from those low-intensity absorptions in the visible range generated by chromium in the same mineral; that (Burns, 1970) and, consequently, to pale colors. is, in spinel, Fez+ causes a grayish blue color, while Transitions for Mn3+ and most of the other metal Cr3+ causes red. The following examples illustrate ions occur with much greater probability, produc- the various factors that influence how metal ions ing stronger absorptions and brighter colors. give rise to color in gem materials. Various treatment methods can have a power- ful influence on the color of gem materials by The Influence of the Valence State. The valence modifying the valence state of the metal ions they state of an ion exerts a strong influence on both the contain. For example, Fe^ can be changed into hue and the intensity of the color. While a number Fez+ by heating in reducing conditions (thus of valence states are possible for each element, turning green beryl to blue aquamarine; see figure only a few are important in gemology (a reflection 7 and Nassau, 1984). Irradiation (X-rays, gamma of the limited range of chemical conditions that rays, etc.), which can easily remove electrons from lead to the formation of gem materials]. For exam- atoms, very often produces the opposite effect of ple, manganese is known in valence states from heat treatment; for example, it converts Fez+ into MnO through Mn^, but it occurs commonly in Fe^, thus turning aquamarine into golden yellow gems as Mn2+ and Mn3+. Beryl containing Mn2+ beryl (Goldman et al., 1978).In the production of exhibits a delicate pink hue (morganite), while synthetic amethyst, irradiation is used to trans- Mn^-containing beryl occurs as bright red (red form Fe3+ into the Fe4+ necessary to obtain the beryl), as seen in figure 6. A different charge of the purple color (Balitslzyand Balitslzaya, 1986).In fact, same element generally produces a different hue. the only way treatment can affect color caused by In the case of manganese, absorption of light in a dispersed metal ions is by modifying the valence material occurs with much greater efficiency if state.

Color in Gems, Part 1 GEMS & GEMOLOGY Fall 1987 131 Figure 7. In beryl, Fe3+ causes yellow and Fez+ causes blue; green beryl is a mixture of Fe3+ and Fez+. The common pac- tice of heating green ber- yl modifies the valence state of the Fe3+ such that the yellow color is removed and only blue (aquamarine) remains. Photo 0 Harold o) Erica Van Pelt.

The Nature of the Neighboring Atoms Influences Ion Coordination. The coordination of an ion refers Color. While the identity of the ion itself is to the number of atoms to which it is directly inlportant, the nature of its neighboring atoms is of bonded and the geometry of this arrangement. equal significance. In most gem materials, the Color-producing ions usually are surrounded by color-producing ion is surrounded by and con- different numbers and arrangements of oxygen nected to oxygen ions. Different neighboring ions. Only three types of coordination are com- atoms, however, will lead to different colors. For monly encountered in gems (in order of fre- example, both green sphalerite and blue spinel are quency): octahedral, tetrahedral, and distorted colored by Co2+ in tetrahedral sites, but the Co2+ cubic (see figure 8).In an octahedron, the central ion in green sphalerite (like the metal ions in all metal ion has six neighbors to which it is bonded; if sulphides) is connected to sulphur, while that of no distortion occurs, they are all the same distance blue spinel is connected to oxygen (Romeijn, 1953; from the atom. The tetrahedron provides four Marfunin, 1979; Shigley and Stockton, 1984). surrounding ions; again, they are equidistant from

132 Color in Gems, Part 1 GEMS & GEMOLOGY Fall 1987 Figure 9. These two stones show the difference Figure 10. Both green peridot and red pyrope-al- in color caused by a difference in coordination: mandine garnet are primarily colored by Fez+. Co2+ is in tetrahedral coordination in [his blue The striking difference in color is caused by the spinel, and in octahedral coordination in the difference in ion coordination, which is octa- pink cobaltocalcite. Photo by Sham McClure. hedral in peridot and distorted cubic in garnet. Photo by Shone McClure.

Figure 8. Three types of ion coordination are commonly found in gem materials: tetrahedral the central metal ion if there is 110 distortion. In (four neighbors), octahedral (six neighbors), and distorted cubic coordination, the central metal ion distorted cubic (eight neighbors). As illustrated has eight neighbors; this coordination is gem- here, the garnet structure exhibits all three of ologically significant only for garnet and zircon. these common coordinations (the tetrahedrons Drastic differences in color may arise when the are in red, 'the octahedrons inblue, and the dis- same metal ion occurs in different coordinations, torted cubsites in yellow). Adapted from No- vak and Gibbs (1971). as illustrated by the examples of Co2+ (figure 9) and Fez+ (figure 10).Cobaltocalcite is popular as a collector's item because of its vivid pink color, which is due (as the name suggests) to cobalt; in calcite it is in octahedral coordination as Co2+. "Cobalt blue" spinel derives its vivid color from Co2+ as well. I11 this case, however, the cobalt is tetrahedrally coordinated, resulting in a striking blue color. A similar dramatic modification in hue is Octahedral encountered with Fez+. The green color of peridot results from the presence of ferrous iron in two slightly distorted octahedral sites, but Fez+ im- Distorted cubic parts a deep red color to almandine garnet (Loeffler Tetrahedral I and Burns, 19761. The basic reason for this differ- ence is the coordination of the Fez+ ion, which in I garnet is a distorted cube (again, see figure 8). To understand why changes in the geometry of the environment of the ion have such a profound effect on color, we must reconsider the orbitals of the central ion. These orbitals project outward toward the oxygen ions in the coordination envi- ronment: Some of the orbitals point directly at these surrounding ions, some fall in between (see figure 11).Electrons in these orbitals of the central ion are electrostatically repelled by the electrons Garnet in the neighboring oxygen ions. The intensity of I repulsion from the negatively charged oxygen ions

Color in Gems, Part 1 GEMS & GEMOLOGY Fall 1987 Figure 12. The strong brown-green pleocl~roismof this 12-cm-long epidote crystal from Pakistan is thought to be due to a geometric distortion of the octahedral iron site. Specimen courtesy of the Sorbonne Collection, Paris; photo 0 Nelly Bariand.

ill ill

depends on the number of oxygen atoms, their depends on the particular electrostatic repulsion distance from the central metal ion, and the experienced during this move. Consequently, the particular orbital the electron is in. When an amount of repulsion will be different in the case of electron in the central ion absorbs light and moves octahedral and tetrahedral environments and, from one orbital to another, the energy required thus, they will produce different colors.

Figure 11. Electrostatic repulsions of different intensities are experienced by electrons in different orbitals of the metal ion, as illustrated here in the case of octahedral coordination. (A) When an orbital of the metal ion points directly toward neighboring oxygen ions, the electrostatic repulsion between the electrons in the orbital and the oxygen ions, both charged negatively, is intense. (B) When an orbital points between oxygen ions, the repulsion is smaller. This difference is ultimately responsible for the different colors that arise from a given ion in different coordination geometry (see figures 9 and 10).

134 Color in Gems, Part 1 GEMS & GEMOLOGY Fall 1987 Pleochroism. The color of a gem mineral also depends on its orientation with respect to the light source, sometimes radically. For example, epidote shows brown in one direction and green in another (figure 12). The cause in epidote is that certain electron transitions are favored along certain crys- tallographic axes. This effect is most prominent in - minerals where the octahedral sites are signifi- e0) c cantly distorted from the ideal geometry. In this 3 case, when an electron moves from one orbital to >Â (0 another, a different amount of energy is required in ne different orientations. (It must be noted, however, -6 that this is only one origin of pleocl~roismin gem z 0 materials. Strong pleochroism can also be seen in ki coloration that involves charge-transfer processes EC or color centers, as will be described in part 2 of sm this series.) 6

Influence of the Details of the Coordination Envi- ronment. A particular ion, in a single valence state, can produce a variety of colors in different gem materials even though it is surrounded by the same Violet I Blue. I Green 1 Y I0 1 Red I I I I ^ number of oxygen ions. For example, ruby, emer- 400 500 600 700 ald, and alexandrite all owe their vivid coloration WAVELENGTH (nm) to Cr3+ 'in octahedral coordination (Loeffler and VISIBLE REGION Burns, 1976).Why, then, do ruby and emerald differ in color, 'and why does alexandrite show different Figure 13. Optical absorption spectra of a ruby colors under different light sources? Figure 13 from Burma, an alexandrite from Tanzania, and shows the optical absorption spectra of these three an emerald from Colombia. As the chromium minerals. The spectra of both ruby and emerald absorption bands shift toward longer wave- consist of two large absorption bands in the visible lengths, the color changes, respectively, from red, to red and green (under different types of region. The major difference is the exact position of light), to green only. the peaks of the two absorption bands. They are situated at highest energy (shortest wavelength) for ruby, which has two transmission windows -one both minerals, will appear at lower energies in centered in the blue (480 nm) between the major beryl than in corundum (again, see figure 13). absorption bands and one centered in the red In alexandrite, which is one of the chromium- (wavelengths longer than 610 nm). Because the eye bearing varieties of chrysoberyl, the Cr^ site is is more sensitive in the red just above 6 10 nm than intermediate between those of ruby and emerald. it is in the blue (see figure 3), the ruby appears red Consequently, alexandrite transmits both bluish (figure 14). On the other hand, the transmission green and red (again, see figure 13).In sunlight, it window for emeralds is centered in the green, will appear mostly green, because this is where where the eye is most sensitive, giving the stones solar light has its maximum intensity and the their rich characteristic color (figure 15). human eye has its greatest sensitivity. When The difference between ruby and emerald can viewed with incandescent light, however, the be explained by the particulars of the crystal- stone appears red because incandescent light con- lographic environment around chromium. Factors tains a relatively larger proportion of red than does such as the distance between chromium and its solar light (an excellent illustration of this color neighboring oxygen atoms, and the details of the change appears in Koivula, 1987). local geometry, contribute to the local electrosta- As another example, red corundum and green tic field about the chromium. These details are zoisite are both colored by Cr3+ in octahedral sufficiently different for the two minerals that the coordination, substituting for AP+ in the crystal absorption features, though similar in shape for structure. The difference in color is due to a

Color in Gems, Part 1 GEMS & GEMOLOGY Fall 1987 observed this "concentration effect" in corundum, spinel, and garnet (e.g., Calas, 1978).In the red Mg- A1 garnet pyrope, Cr3+ ions are present at low concentration, and the Cr-0 distance is 1.96 A (Calas, 1978). In the deep purple Mg-Cr garnet lznorringite, however, Cr-^ ions occur in the same coordination, but at higher concentration, with a Cr-0 distance of 2.03 A (Berry and Vaughan, 1985). Thus, in a single mineral group, such as garnet, an increase in concentration of Cr3+ will lead to an increase in the Cr-0 distance and modification of the color from red to purple.

Remarks. The various phenomena that we have described can be approached quantitatively by the use of chemical theories such as crystal field theory (Burns, 1970). These theories can explain the color in gems equally well in the case of either a major constituent (such as iron in peridot and garnet) or a minor component (such as chromium in ruby and emerald). The same type of reasoning can be applied to dispersed metal ions in noncrys- talline materials such as glasses; for example, the peridot-like green color of tektites and moldavites is also due to Fez+. Oversimplifying a little, metal ions create basically the same spectra in glass simulants as in the gems themselves. Table 1 lists the variety of colors caused by Figure 14. Because of the position of the Cr3+- absorption bands in its visible spectrum, ruby different metal ions in gem materials. When re- has a red body color. In addition, rubies not viewing this list, please keep in mind that many only transmit red, but they also emit it, so that gems are colored by a combination of causes (some their color can be reinforced by the strong red of which will be discussed later in this series of luminescence, especially in Burmese stones. articles). For example, the different shades of red in The deep red body color and natural red lumi- ruby are due to the influence of minor absorptions nescence of these two 20-ct rubies (set in ear- caused by small amounts of dispersed iron and rings) is enhanced by the cabochon cut. Cour- vanadium ions (Harder, 1969).Also, the same color tesy of Collection Cha~imet,Paris; photo 0 (e.g., green) can occur in a given gem material (e.g., Nelly Bariand. nephrite) for different reasons (dispersed octa- hedral Cr3+ produces "emerald-green," while dis- difference in the distance between the metal ion persed octahedral Fe2+ gives a more yellowish (chromium)and the neighboring oxygen atoms. In green). zoisite structure, Cr3+ occupies a site where the average metal-oxygen distance is 1.967 A (Dollase, CONCLUSION 1968).In corundum structure, however, it is much The first article of this series on the origin of color shorter- 1.913 A (Newnham and De Haan, 1962). in gem materials has reviewed the best-known Therefore, the Cr3+ ion experiences more electro- cause of color: absorption of light by dispersed static repulsion in corundum, and its absorption metal ions. We have demonstrated that not only is features are shifted to higher energies than in the identity of the metal ion important, but its zoisite, causing a contrast in color. valence state, the nature of the neighboring atoms, One factor that might influence the environ- its coordination, and the details of its environment ment of a given ion, in particular the metal-oxygen may also have a dramatic effect 011 the color of a distance, is its concentration. Various authors have gem material. The only way treatment can affect a

136 Color in Gems, Part 1 GEMS & GEMOLOGY Fall 1987 Figure 15. The vivid green of these Colombian emeralds results from the distinctive coordination en- vironment of the color-causing Cr3+ ions. The emerald in the pendant weighs 37 ct; the two drops in the earrings weigh a total of 49 ct. Jewelry courtesy of Harry Winston, Inc.; photo 0 Harold ed Erica 'Van Pelt.

Color in Gems, Part 1 GEMS & GEMOLOGY Fall 1987 137 --- TABLE 1. Dispersed metal ions and the colors they cause in various gem materials.

Ion and Ion and coordination Color and gem material coordination Color and gem material

Ti3+ No known gems where the origin of color has Mn2+ Pink: beryllmorganite (Woods and Nassau, octahedral been positively proved to be dispersed Ti3+, octahedral 1968); rhodocrosite (Lehrnann, 1978); lep- although the case of rose quartz is under idolite (Faye, 1968); titanite (Mottana and discussion (see Cohen and Makar, 1985) Griffin, 1979) Greenish yellow: some rare elbaites (Ross- v4 + Blue: zoisitelheat treated = tanzanile octahedral (Hurlbut, 1969) man and Mattson, 1986) Green: apophyllite (Rossman, 1974) Mn2+ Orange: spessartine (Manning, 1967a) dist. cubic v3 + Blue: axinite (Schmetzer, 1982) octahedral Brown-violet: zoisiteluntreated (Hurlbut, 1969) Fe3 + Yellow: chrysoberyl (Loeffler and Burns, Green: beryllvanadium emerald (Wood and octahedral 1976) Nassau, 1968); grossularllsavorite (Gubelin Yellow green: jadeite (Rossman, 1981); epi and Weibel, 1975); some kyanites, diopsides, dote (Burns, 1970); andradite (Manning, uvites, spodumenes and kornerupines 1967b) (Schmetzer, 1982) F@+ Yellow: orthoclase and other feldspars Color-change effect: corundum and some tetrahedral (Hofmeister and Rossman, 1983); sillimanite rare pyropes and pyrope-spessartines (Rossman et al., 1982) (Schmetzer et al., 1980) Fe2+ Blue: elbaitelindicolite (Dietrich, 1985) Cr3+ Blue: kornerupine (Schmetzer, 1982) octahedral Yellowish green to green: olivinelperidot octahedral Green: beryllemerald, spinel (Vogel, 1934); (Loeffler and Burns, 1976); diopside, spodumenelhiddenite, diopsidelchrome actinolitelnephrite (Burns, 1970); natural diopside, jadeitelchrome jadeite, nephrite, glasseslmoldavite, tektite (Pye et al., 1983) euclase, andraditeldemantoid, some rare olivines, variscite (Anderson, 1954-55); Fez+ Blue: gahnite and "gahnospinel" (Dickson and titanitelchrorne sphene, zoisite (Schrnetzer, tetrahedral Smith, 1976)

1982); uvarovite (Calas, 1978) Fe2+ Red: pyrope, pyrope-almandine (rhodolite), Color-change effect: chrysoberyllalexandrite dist. cubic almandine (Manning, 1967a) (Farrell and Newnham, 1965); some pyropes co2+ Pink: calcitelcobaltocalcite (Webster, 1970) (Schmetzer el al., 1980) octahedral Green: sphalerite (Marfunin, 1979) Red to violet: corundum/ruby, spinel (Vogel, 1934); some pyrope (Manning, 1967a); co^ Blue: spinel (Shigley and Stockton, 1984); taaffeite (Schrnetzer, 1983); topaz tetrahedral staurolite (Cech et al, 1981) (Anderson, 1954-55); stichtite Ni2+ Green: clay inclusions in chrysoprase and Mn3+ Red to violet to pink: beryllred beryl octahedral some opals, e.g., prase opal (Koivula and octahedral (Shigley and Foord, 1984); piemontite (Burns, Fryer, 1984) 1970); some elbaiteslrubellites, sugilite cu2+ Blue: turquoise and chrysocolla (Lehmann, (Shigley et al., 1987); rhodonite (Gibbons et octahedral 1978); azurite (Marfunin, 1979) al., 1974); zoisitelthulite Green: malachite and dioptase (Lehmann, Green: andalusitelviridine (Smith et al., 1982) 1978) color caused by dispersed metal ions is by modify- ters. These two causes of color will be examined ing the valence state. In recent years, we have and illustrated with a number of examples in the become aware of the importance of other types of next article in this series. The least common coloration, such as charge transfer and color cen- origins of color in gem materials, band theory and ters. Heat treatment can induce or increase charge physical optics, will be discussed in the third and transfers, and irradiation often creates color cen- last part.

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138 Color in Gems, Part 1 GEMS & GEMOLOGY Fall 1987 tion and Mossbauer spectra of stanrolite and spinel. Mottana A,, Griffin W.L. (1979)Pink titanite (greenovite)from Canadian Mineicilogist, Vol. 14, pp. 206-215. St. Marcel, Valle D'Aosta, Italy. Rendiconti Societd Ital- Dietrich R.V (1985) The Tourmaline Group. Von Nostrand ianci di Minerulogia e Petrologia, Vol. 35, No. 1, pp. Rcinhold Co., New York. 135-143. Dollase W.A. (1968) Refinement and comparison of the struc- Nassau K. (1975) The origin of color in gems and minerals. turcs of zoisite and clinozoisite. American Mineralogist, Gems a) Gemology, Vol. 15, pp. 2-1 1. Vol. 53, pp. 1882-1898. Nassau K. (1983) The Physics and Chemistry of Color: The Duplessis Y,, Ed. (1985)Les Couleurs Visibles et Non Visibles. Fifteen Causes of Color. John Wiley & Sons, New York. Editions du Rocher, Paris. Nassau K. (1984) Gemstone Enliancement. Butterworths, Farge Y., Fontana M.P. (1979)Electronic and Vilmtional Prop- Stoneham, MA. erties of Point Defects in Ionic Crystals. North Holland Newnham R.E., De Haan Y.M. (19621 Refinement of the Publishing, Amsterdam. aA120i, Ti20.3, V203 and Cr203 structures. Zeitschrift fur Farrell E.F., Newnham R.E. (1965) Crystal field spectra of Kristallographie, Vol. 11 7, pp. 235-237. chrysoberyl, alcxandrite, peridot and sinhalite. American Novak G.A., Gibbs G.V (1971) The crystal chemistry of the Mineralogist, Vol. 50, pp. 1972-198 1. silicate garnets. American Mineralogist, Vol. 56, pp. Faye G.H. (1968) The optical absorption spectra of certain 791-825. transition metal ions in muscovite, lepidolite and Pouget (1752) Traiti des Pierres Pricieiises. As cited in P. fuchsite. Canadian Journal of Earth Sciences, Vol. 5, pp. Bariand and J. E Poirot (1985) Laroiisse des Pierres Pre- 31-38. cieuses, Larousse, Paris. Fritsch E, (1985) La couleur des mineraux et des genlmes. Pye L.D., O'Keefe J.A., Frkchette VD., Eds., (1984) Natural Premiere partie: Des tribulations d'un electron a I'inter- Glasses. North Holland Publishing, Amsterdam. ieur d'un atome isole. Monde e) Minkraux, Vol. 67, pp. Romeijn F.C. (1953)Physical and crystallographical properties 20-2.5. of some spinels. Philip Research Reports, Vol. 8, pp. Fyfc W.S. (1964) Geochemistry of Solids. McGraw-Hill Book 304-320. Co., New York. Rossman G.R. (1974)Optical spectroscopy of green vanadium Gibbons R.V., Ahrens TJ., Rossman G.R. (1974) A spec- apophyllite from Poona, India. American Mineralogist, trographic interpretation of shock-produced color change Vol. 59, pp. 621-622. in rhoclonite (MnSiO,?):The shock-induced reduction of Rossman G.R. (1981) Color in gems: The new technologies. Mn(Il1) to Mn(l1). American Mineralogist, Vol. 59, pp. Gems çt Gemology, Vol. 17, pp. 60-71. 177-182. Rossman G.R., Grew E.S., Dollase W.A. (1982) The colors of Goldman ,D,S., Rossman G.R., Parkin K.M. (1978) Channel sillimanite. American Mi~~eralogist,Vol. 67, pp. 749-761. constitutcnts in beryl. Physics and Chemistry of Min- Rossnlan G.R., Mattson S.M. (1986) Yellow, manganese-rich erals', Val. 3, pp. 225-235. elbaite with manganese-titanium intervalence charge Giibelin E.J.,Weibcl M. (1975)Green vanadiun~grossulargarnet transfer. American Mineralogist, Vol. 71, pp. 599-602. from Lualenyi, near Voi, Kenya. Lapidary Journal, Vol. 29, Schn~etzerK., Bank H., Glibelin E. (1980)The alexandrite effect pp. 402-426. in minerals: Chrysoberyl, garnet, corundum, fluorite. Harder H. (1969) Farbgebende Spurenelemente in den Neiies Jahrbiich fur Mineralogie Abliandlungen, Vol. 138, natiirlichen Korunden. Neiies Idhrbiich fiIr Minercrlogie pp. 147-164. Abhandlungen, Vol. 1 10, No. 2, pp. 128-141. Schmetzer K. (1982)Absorptionsspektroslcopie und Farbe von

Hofmeister A.M., Rossman G.R. (1983) Color in feldspars. In V-3 + - haltigen naturlichen Oxiden und Silikaten-ein pH. Ribbe, Ed., Reviews in Mir~eralogy,Vol. 2, 2nd ed.: Beitrag zur Kristallchemie des Vanadiums. Neiies Jahr- Feldspar Mineralogy, Mineralogical Society of America, bucli fiir Mineralogie Abhandlungen, Vol. 144, pp. Washington, DC, pp. 271-280. 73- 106. Hurlbut C.S. (1969) Gem zoisite from Tanzania. American Schmetzer K. (1983) Crystal chemistry of natural Be-Mg-Al- Mineralogist, Vol. 54, pp. 702-709. oxides: taaffeite, taprobanite, musgravite. NeuesJahrbtich Kittel C. (19561Introduction to Solicl State Physics, John Wilcy fur Mineralogie AL~I~aiidl~rngen,Vol. 146, No. 1, pp. 15-28. & Sons, New York. Shigley J.E., Stockton C.M. (1984) "Cobalt-blue" gem spinels. Koivula 1.1. (1987)Gem news. Gems in) Gemology, Vol. 23, No. 2, Gems Gemology. Vol. 20, pp. 34-4. pp. 122-124. Shiglcy J.E., Foord E.E. (1984) Gem-quality red beryl from the Koivula J.!., Fryer C.W. (1984) Green opal from East Africa. Wah-Wall Mountains, Utah. Gems 01 Gemology, Vol. 20, Gems &> Ceniology, Vol. 20, No. 4, pp. 226-227. No. 4, pp. 208-221. Kunz G.F. (1913) The Curious Lore of Precious Stones. Rc- Shigley J.E., Koivula J.I., Fryer C.W. (1987)The occurrence and printed by Dover Publications, New York, 1971. gemological properties of Wessels Mine sugilite. Gems 0) Lehmann G. (1978)Farben von Mineralien und ihre Ursachen. Gemology, Vol. 23, No. 2, pp 78-90. Fortschritte der Mineralogic, Vol. 56, No. 2, pp. 172-252. Smith G., Hilenius U., Langer K. (1982) Low temperature Locffler B.M., Burns R.G. (1976)Shedding light on the color of spectral studies of Mn-^-bearing andalusite and epidote

gems and minerals. American Scientist, Vol. 64, pp. type minerals in the range 30000-5000 cm - I. Physics and 636-64 7. Chemistry of Minerals, Vol. 8, pp. 136-142. Manning P.G. (19673) The optical absorption spectra of the Vogel l? (1934) Optische Untersuchungen am Smaragd und garnets alniandine-pyrope, pyrope and spessartine and einigen anderen durch Chrom gefarbten Mineralien. some structural interpretations of mineralogical signifi- Neiicss lalirbuch fur Mineralogie, Geologie und Paleon- cance. Canadian Mineralogist, Vol. 9, No. 2, pp. 237-251. tologie, Vol. A68, pp. 401438. Manning P.G. (1967b)The optical absorption spectra of some Wasserman J.S. (1978) Color Vision. John Wiley & Sons, New andradite and the identification of the ^'A,+ 'Â¥A4E(G) York. transition in octahedrally bonded Fe3+. Canadian Journal Webster R. (1983) Gems, Their Sources, Descriptions and of Earth Sciences, Vol. 4, pp. 1039-1047. Identification. Butterworths, London. Marfunin A.S. (1979)Physics of Minerals and Inorganic Mate- Wood D.L., Nassau K. (1968)The characterization of beryl and rials, an Introduction. Transl. by N.C. Egorova and A.G. emerald by visible and infrared absorption spectroscopy Mishchenko, Springer Verlag, Berlin. American Mineralogist, Vol. 53, pp. 777-800.

Color in Gems, Part 1 GEMS & GEMOLOGY Fall 1987 139 THE LENNIX SYNTHETIC EMERALD

- - p~- - - - - By Giorgio Graziani, Edward Giibelin, and Maurizio Martini

The Lennix synthetic emerald, currently s the techniques of crystal growth have become n~anufacturedin France, is a dark green, A increasingly sophisticated, greater numbers and moderately transparent to translucent types of synthetic emeralds have entered the marketplace. material grown by flux fusion. With the One of these products, the Lennix synthetic emerald, is microscope, zones of lighter and darker currently being manufactured by the Societe France pour green are evident. For the most part, the la Distribution de Produits Manufactur6s1 in Cannes, gemological properties of this synthetic emerald overlap those of natural einer- France (figure 1).In 1966, Mr. L. Lens, now president of the aids, although the low refractive-index manufacturing company, first accomplished the synthesis and specific-gravity values are good indi- of microscopic emerald clusters. Years of research and cators that this material is synthetic. The refinement followed, and in the period 1982-1983, Mr. presence of "wispy veil" inclusions pro- Lens finally obtained gem-quality synthetic emeralds in vides conclusive proof of synthetic origin, sizes suitable for use in jewelry. Mr. Lens reports that the as do the chemical analyses, infrared production capacity of the firm is currently 50,000 ct of transmission spectra, and cathodo- rough crystals per year, an amount that could be doubled luminescence. with the addition of a second furnace. The material is now available in France (and has already been mistaken for "African emerald" by some jewelers). Since the distribution of the material is controlled by a Canadian company, it is likely that this material will soon be introduced in Canada and the United States (E. Fritsch, pers. comm., 1987). Although Farn (1980)examined a number of the early ABOUT THE AUTHORS Lennix synthetic emeralds and pointed out some distinc- Dr. Graziani is professor of mineralogy at the Uni- versity of Rome; Dr. Gubelin, a prominent gemolo- tive characteristics of these stones, the present authors felt gist and author, is from Meggen, Switzerland; Dr. that a detailed examination of the material and its inclu- Martini is a gemologist at the Laboratory of Gem- sions was warranted to describe the means by which it mological Analysis, Rome. could be separated from natural emeralds and other Acknowledgments: The authors wish to thank Dr. synthetics. To aid in this project, Mr. Lens supplied eight J. Ponahlo, Director of the Austrian Gemmological Research Institute of the E.O.G.C.,Vienna, for his rough crystals and one faceted stone. The samples were help with the cathodoluminescence experiments, first tested for the standard gemological properties, and and Mr. L. Lens, of the French Society for the Dis- tribution of Manufactured Products, Cannes, for then chemical analyses, cathodoluminescence, X-ray to- providing samples and for his much-appreciated pography, X-ray diffraction, and advanced inclusion an- suggestions. The work was supported by a grant alyses were performed. The results of these tests are from the University "La Sapienza," Rome, for the provided here. study of mineral inclusions, and by a contribution from the Cassa di Risparmio di Roma, Italy, for gemological research. METHOD OF SYNTHESIS 0 1987 Gemological Institute of America Mr. Lens reports that the Lennix synthetic emeralds are

140 The Lennix Synthetic Emerald GEMS &. GEMOLOGY Fall 1987 Figlire 1. A 1.32-ct fac- eted Lennix synthetic emerald and a 1.42-ct crystal section of the material. Photo 0 Tino Hammid.

grown by the flux-fusion process. Crystallization Refractive Indices. When tested with a gemologi- takes place at atmospheric pressure, and follows a cal refractometer, the faceted Lennix synthetic rather involved cycle of temperatures, in the region emerald was determined to be uniaxial negative. of 100@  100¡Cestablished to compensate for Refractive indices were determined on microsam- variations in the composition of the flux during the pies isolated by means of the MEA apparatus growth process. (Graziani, 1983))from within both the light and dark green areas. TEST SAMPLES AND The values* are: = 1.556-1.562 (1.559)and VISUAL APPEARANCE a) = 1.558-1.566 (1.562), with a corresponding The synthetic samples examined by the authors birefringence for the mean values of 0.003, for the are in the form of eight tabular hexagonal crystals light green areas; and = 1.555-1.565 (1.560))a) = and one cut specimen. The rough crystals are 1.560-1.568 (1.5641, with a mean birefringence of characterized by a predominant basal pinacoid. 0.004, for the dark green areas. The faceted stone They range in size from 13.9 x 9.6 x 3.0 mm to 9.2 shown in figure 1, for example, revealed refractive x 6.9 x 3.2 mm; the cut sample weighs 1.30 ct and indices of = 1.559, a) = 1.562, with a bi- measures 7.90 x 6.12 x 3.12 mm. To the unaided refringence of 0.003. eye, the Lennix synthetic emeralds appear dark The low values of the light green areas (and the green and homogeneous in color (again, see figure stone in figure 1) are characteristic of flux-grown 1). Microscopic observations, however, reveal the synthetic emeralds and provide some indication of presence of more intense peripheral color zones synthetic origin. However, an identification parallel to the c-axis. should not be based on these values alone. The samples range in clarity from moderately to heavily included. Consequently, they vary from Dichroism. Using a dichroscope, we observed stones of medium transparency to those with areas pronounced pleochroic colors of bluish green for that are translucent to almost opaque. the ordinary ray and yellowish green for the extraordinary ray, both also commonly observed in STANDARD natural emeralds. GEMOLOGICAL TESTING The samples were subjected to standard gemologi- cal tests. The results are shown in table 1 and The extreme values of the constants are given, with mean discussed below. values in parentheses.

The Lci-mix Synthetic Emerald GEMS & GEMOLOGY Fall 1987 shown in figure 1 was examined with a Beck hand- TABLE 1. The gemological properties of the Lennix flux- grown synthetic emerald. held type of spectroscope. The observed spectrum appeared to be the same as that previously de- Properties that overlap scribed for both synthetic and natural emerald those of natural emeralds (Liddicoat, 1981). This optical absorption spec- Pleochroism Strong bluish green parallel to the c-axis; yellowish green perpendicular to the trum was confirmed, using a Cary 219 dual-beam c-axis. spectrophotometer, over the spectral range from Absorption Optic-axis direction absorption lines at 400 to 800 nm. The following were identified: a spectrum8 477, 637, 646, 662, 680, and 683 nm; a doublet at 683 and 680 nm; bands at 662, 646, and vague general absorption from 400 to 480 nm and a broad band of absorption 637 nm; and a wide band between 610 and 590 nm. between 590 and 610 nrn. Perpendicular An additional line at 477 nm can be seen only to optic-axis direction: same as above, with when looking at the spectrum down the optic axis the exception that the 477-nm line is absent. direction (i.e.,parallel to the c-axis);it is not visible Color-filter when the spectrum is examined perpendicular to reaction Strong red the optic axis. This phenomenon was observed Fluorescence with both the "hand-held" spectroscope and the Lona-wave U.V. Briaht red spectrophotometer. short-wave U.V. weak orange-red Key Identifying properties Fluorescence. When exposed to long-wave ultra- Refractive Light green: E = 1.556-1 562 (1.550) violet radiation, the specimens glowed bright red, indices" td = 1.558-1.566 (1.562) and with short-wave U.V radiation they revealed Dat een: = 1.555-1.565 (1.560) w = 1.560-1,568 (1.564) both transparency and a dim orange-red fluores- igenceb Light green = 0,003 cence. While this fluorescence might be an indica- Dark green = 0.004 tor that the stone is synthetic, it should be noted Specific Around 2.65-2.66 that some high-chromium Colombian emeralds gravitp will fluoresce bright red to long-wave U.V radia- Inclusions Opaque, tube-like inclusions aligned tion. Exposure to X-rays caused a distinct, yet dull, parallel to the c-axis; sequential growth layers, with primary flux inclusions and red fluorescence. foreign crystallites; slender prismatic crystals of synthetic phenakite and - CHEMISTRY AND synthetic beryl; "wispy veils." two-phase inclusions I ADDITIONAL TESTING Chemical Analyses. Each specimen was analyzed "As observed through a hand-held type of spectroscope. by means of a JEOL JXA-50A electron microprobe [>Theextreme values of the constants are given, with mean values in parentheses. Birefringences are given lor the mean on both the pale green and the deep green zones. values. The chemical data reported in table 2 refer to ^Estimated with heavy liquids. average values obtained from no less than five spots for each sample. The data show fairly high contents of FeO and Color-Filter Reaction. Observed through the MgO for a synthetic emerald and low amounts of Chelsea filter, the crystals appear a vivid red, again alkalies as compared to most natural emeralds. as can be seen in many natural emeralds. However, the FeO and MgO contents are lower Specific Gravity. The specific-gravity values for than the average in most natural emeralds and, flux-grown synthetic emeralds of various manu- along with the low content of alkalies, may be facturers are frequently lower than the values for responsible for the low refractive-index, bi- natural emeralds; flux-grown synthetic emeralds refringence, and specific-gravity values (Folinsbee, usually float when tested in a standard 2.67 1941; Sherstyuk, 1958; Winchell and Winchell, (specificgravity) heavy liquid. A few of the Lennix 1951). The chromium content in the deep green synthetic emeralds were tested in 2.67 liquid; on areas is high, but is comparable with data reported the basis of the rate of ascent, the specific gravity for natural and other synthetic emeralds. was estimated to be approximately 2.65-2.66. Cathodoluminescence. Cathodoluminescence de- Absorption Spectra. The visible-light absorption terminations were carried out on all samples using spectrum of the faceted Lennix synthetic emerald a luminoscope manufactured by Nuclide Corp.

142 The Lennix Synthetic Emerald GEMS & GEMOLOGY Fall 1987 USA. Electrons were produced using pure helium as a carrier gas. The data obtained were quite TABLE 2. Results of the chemical analyses of the pale green and deep green areas of eight rough and one similar for all samples. Red luminescence similar faceted Lennix synthetic emerald.a to or weaker than that of Chathain or Linde hydrothermal synthetic emeralds - but more in- Pale green areas Deep green areas (wt.%) (wt.%) tense than that of natural Colombian emeralds- -. was observed in all cases. In some of the synthetic 65.83 18.02 Lennix emeralds tested, the luminescence excited 0.57 by cathode rays was different at the edges and 0.50 within a narrow outer zone (red)from that seen in 13.06 0.46 the interior (violet-blue or purple). No other emer- 0.07 alds (synthetic or natural) tested thus far have 0.32 displayed the purple or bright violet-blue lumines- 0.14 cence observed in the Lennix specimens. 0.06

X-Ray Diffraction Data. Microsamples (about 20-30 pm in diameter) were isolated by means of 'All oxides were determined by electron microprobe except, Be was the MEA apparatus (Graziani, 19831, within both determined by the pyrophosphate method, and 1-1,O plus CO, were determined thermogravimelncally The results reported are average the deep green and the pale green zones of all the values. specimens. Subsequently, X-ray diffraction pat- bTolal iron as Fed. cThe lollowing elements were checked but not detected: Ti, V, Ca, terns were obtained using a Gandolfi camera Ba, Cs. Not recognized with spectrographic method: Li. (Gandolfi, 19671, and unit-cell parameters were estimated by a least-squares refinement of the diffraction data (Farinato and Loreto, 1975; De Angelis ita]., 1977))indexed by comparison with aids seem to be totally absent, as would be ex- those listed by JCPDS. The results for the light pected for a flux-grown synthetic emerald green areas were a = 9.203 Â 0.002 A, -c = 9.18 1 ? (Flanigen et al., 1967))thus yielding another valu- 0.004 A; for thedarlz green areas, they were -a = able means of distinction. However, infrared spec- 9.202 Â 0.003 A, -c = 9.187 Â 0.005 A. tra in the same range that were obtained from polished slabs oriented parallel to the c-axis X-ray Topography. Experiments were carried out showed less distinct features. on slabs of the synthetic Lennix emeralds cut perpendicular to the c-axis and polished by stan- Microscopic Examination of Inclusions. The Len- dard procedures (Scandale et al., 1979). nix synthetic emerald samples were examined The tests were performed by means of a Lang with a gemological binocular microscope in trans- camera, recorded on llford high-resolution plates, mitted light and under crossed polar~.The speci- using MoKoiradiation. The topography was re- mens are characterized by a variety of inclusions markable in the contrasting features that covered that may generally be divided into five categories: the entire surface and permit reconstruction of the growth history of the examined crystal. In fact, the Opaque, tube-like inclusions aligned preferen- sample resulted from the aggregation of different tially parallel to the c-axis (figures 2-4) smaller crystals around a subhexagonal central Clusters of inclusions along the borders of nucleus. This kind of growth is quite different sequential growth zones that parallel the edges from that of natural emeralds, in which the crys- of the basal pinacoid (figure 5) tals grew during a slow cooling of the parent solution, and is thus typical of synthetic beryl Slender, subhedral prismatic crystals of syn- grown in flux conditions. thetic phenalzite and beryl (figures 6-8) Secondary flux-lined healed fractures that at Infrared Spectra. Infrared spectra in the range 4000 low magnification look like "wispy veils" (fig- to 600 cm-I were obtained on a Perlzin Elmer 398 ure 9) filter grating spectrometer, using 1 mg of beryl in Two-phase inclusions grouped along the edges 200-mg KBr discs. The bands at 3590 and 3694 of the basal pinacoid and sometimes parallel to cm - 1 that are normally observed in natural einer- the c-axis (figures 4 and 10)

The Lennix Synthetic Emerald GEMS & GEMOLOGY Fall 1987 143 Figure 2. This partly flux-filled (Moos) tube- Figure 3. A different view of a number of tube- like inclusion in a Lennix synthetic emerald is like inclusions similar to the one seen in surrounded by peripheral synthetic beryl crys- figure 2 shows that they are oriented in chan- tals. A number of wispy veil-like inclusions nels that run parallel to the c-axis. Transmitted characteristic of flux-grown synthetic emeralds light, magnified 100~. are also evident. Transmitted light, magni- fied 30x.

Figure 5. Color zones, representing the various stages of growth of the synthetic emerald, echo Figure 4. These irregular, opaque MOO,? flux in- the hexagonal frame of the Lennix crystal clusions are accompanied by peripheral syn- growth. On this basal plane, a number of di- thetic beryl crystallites and two-phase inclu- chroic synthetic beryl crystals are evident. sions. Transmitted light, magnified 64 x . Transmitted light, magnified 10 x .

144 The Lennix Synthetic Emerald GEMS & GEMOLOGY Fall 1987 Figure 6. This spider-like configuration in a Figure 7. Individual crystals of synthetic beryl Lennix synthetic emerald proved to be a group- tire observed at right angles to their c-axes in ing of crystals of synthetic phenakite. Transmit- this Lennix synthetic emerald. Crossed polars, ted light, magnified lOOx. magnified 30 x .

Opaque, Tube-likeInclusions, X-ray transmis- cal composition to the host, particularly to the sion micrographs were made on the opaque, deep green zones (table 2). Consequently, these tube-like inclusions oriented in channels (figures inclusions were determined to be synthetic beryl 2-4). These analyses identified subordinate crys- (figures 7 and 8). tals of synthetic beryl along the channel walls, and a thin film of flux which was opaque to X-ray microri$ograPhy. Chemical analysis of the flux Figure 8. An opaque black flux inclusion marks proved'ii to be molybdenum oxide (Mooa). the center of this greatly enlarged synthetic be- ryl crystal in a Lennix synthetic emerald. Growth Zoning and Associated Inclusions. Crossed polars, magnified 150 x . Optical observations attest to the presence of various stages of crystal growth. Along the edges of these growth zones, two kinds of associated inclu- sions are evident: minute euhedral synthetic beryl crystals (figure 5) and clusters of synthetic phe- nakite. X-ray diffraction patterns identified the latter inclusions (JCPDS card no. 9-431). This identification was confirmed by microprobe anal- ysis and subsequent stoichioinetric elaboration of the chemical data.

Other Crystal Inclusions. The Lennix syn- thetic emerald also contains discrete, minute, acicular, prismatic crystals that sometimes con- sist of tri- and poly-angular associations (figure 6). The chemical composition of these inclusions is typical of phenakite and very similar to that of the clusters described previously. Transparent subhedral prismatic crystals (ap- proximately 0.05 x 0.03 mm) were also observed perpendicular to the c-axis of the synthetic host emerald. Not only are the refractive indices of these crystal inclusions similar to those of the synthetic host emerald, but microchemical an- alyses also revealed that they are similar in chemi-

The Lennix Synthetic Emerald GEMS & GEMOLOGY Fall 1987 Figure 10. In this greatly enlarged two-phase in- clusion, the large oval bubble that corroborates the second phase is probably in a glassy flux Figure 9. These delicate "wispy veils" are actu- relic. The inclusion runs parallel to the c-axis of ally secondary flux-lined healed fractures in the the host. Transmitted light, magnified 100~. Lennix synthetic emerald. Transmitted light, magnified 15 x .

(sealing),beryl crystallization occurred. This phe- The whole crystal also contains many two- nomenon is very close to that described by Yer- phase inclusions in wisp- or veil-like configura- malzov (1965)as a deposition of the cognate subs- tions (figure 9). These "wispy veilsJt-more pre- tance on the inclusion wall. cisely secondary flux-lined healed fractures - are typical of flux-grown synthetic stones. In addition, CONCLUSION small, sporadic swarms of two-phase inclusions For the gemologist, the very fact that the Lennix occur either at right angles to the c-axis of the synthetic emeralds are so heavily included can synthetic emerald host or, more frequently paral- cause problems, because they superficially resem- lel to the c-axis (figure 10). ble poor-quality natural emeralds. If, however, Tb determine homogenization temperatures wispy veil-like partially healed fractures (similar for these inclusions, we used a Nikon Optiphot Pol. to those shown in figure 9) are present, then XTP-11 microscope equipped with a Fluid Inc. gas regardless of the other inclusions (which may flow heatinglfreezing system for temperatures up somewhat resemble those seen in natural emer- to 700° and a Leitz 1350 device for higher alds), the stone can be identified as synthetic. The temperatures. At least nine hours of isothermal low refractive-index and specific-gravity values heating were used for each run. Homogenization are also indicative of flux-grown synthetic emer- could not be observed up to 800°C alds; when these are obtained in conjunction with TWO-phaseinclusions with internal crystalliz- the observation of "wispy veils," they conclusively ation products were sectioned by MEA for analysis. prove synthesis. Optical investigations showed that the internal Where available, more sophisticated chemical walls of these inclusions are covered by irregularly analyses, infrared spectra, and cathodolumines- shaped crystals with a chemical composition very cence experiments all provide effective means of close to that of the synthetic host emerald. differentiating the Lennix synthetic emerald from These considerations suggest that, after the both natural emeralds and other synthetic emer- formation of the cavities and before their closure alds.

146 The Lennix Synthetic Emerald GEMS & GEMOLOGY Fall 1987 REFERENCES De Angelis G., Farinato R., Loreto L. (1977)The crystal lattice Petrografica Ada, Vol. 13, pp. 67-74. constants refinement: a least-squares procedure for the Graziani G. (1983)Advances in the study of mineral inclusions. direct or reciprocal case. Rendiconti delta Societh Italians Neues jarbuch fiir Mineralogie Monatshefte, Vol. 11, pp. di Mineralogia e Petrologia, Vol. 33, pp. 3-14. 481-488. Farinato R., Loreto L. (19751 A least-squares refinement of Liddicoat R.T. Jr. (198 1)Handbook of Gem Identification, 11 th crystals lattice constants and evolution of their errors, ed. Gemological Institute of America, Santa Monica, CA. using the direct unit-cell. Rendiconti della Societci Ital- Scandale E., Scordari F., Zarka A. (1979)Etude des dkfauts dans ian~di Mineralogia e Petrologia, Vol. 31, pp. 486-500. des n~onocristaiixnaturels de beryl, 1: Observations des Farn A.E. (1980)The Lennix emerald. lour~icilof Gemmology, dislocations. journal of Applied Crystallography, Vol. 12, Vol. 17, No. 2, pp. 73-80. pp. 70-77. Flanigen E.M., Breck I.W, Mumbach N.R., Taylor A.M. (1967) Sherstynk A.I. (1958)The influence of isomorphous impurities Characteristics of synthetic cn~eralcls.American Miner- in beryl on its refractive indices. Doklady Akade~niiNauk alogist, Vol. 52, pp. 744-772. SSSR, Vol. 2, pp. 51-56. Folinsbee R.E. (1941)Optic properties of cordierite in relation Winchell A.M., Winchell H. (1951)Elements of Optical Miner- to alkalies in the cordieritc-beryl structure. American alogy, Vol. 2, 4th ed. John Wiley, New York. Mineralogist, Vol. 26, pp. 485-500. Yermakov N.P. (1965) Research on the Nature of Mineral- Ganclolfi G. (1967) Discussion upon methods to obtain X-ray forming Solutions, 1st ed. Pergamon Press, New York. "powder patterns" from a single crystal. Minernlogica et

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The Lennix Synthetic Emerald GEMS & GEMOLOGY Fall 1987 147 NOTES AND* NEW TECHNIQUES

SYNTHETIC OR IMITATION? AN INVESTIGATION OF THE PRODUCTS OF KYOCERA CORPORATION THAT SHOW PLAY-OF-COLOR By Karl Schmetzer and Ulrich Henn

The products of Kyocera Corp. that show play-of-color ded observations at five different magnifications were investigated to determine if the materials are ranging from the atomic level to inspection by the truly synthetic opal or rather are opal simiilants. The nalzed eye. It also included the following four authors propose that, because these materials con- criteria on the basis of which man-made gem tain no water, they do not match the composition of materials must be essentially identical to their natural opals and, thus, should be designated opal natural counterparts to be labeled synthetic: (1) simulants. The gemological properties of the samples examined are also provided, including those by chemical composition, (2) crystal structure, (3) which the Inamori material can be separated from submicroscopic structures, and (4)appearance to natural opal. the naked eye. These criteria have been applied in discussions of non-single-crystal materials such as man-made turquoise (Schmetzer and Bank, 1980, 1981; Lind et al., 1983a and b), man-made opal (Schmetzer, 1983a, 19841, and man-made lapis Gem materials showing play-of-color are manu- lazuli (Schmetzer, 1983b, 1985). factured in Japan by Kyocera Corp. and sold under In the case of the products of Gilson that show the trade name lnamori Created Opals (figure 1). play-of-color, the man-made materials do not The first gemological reference to these materials match natural opals in chemical composition, was by Fryer et al. (1983); in this short note, the primarily because of the absence of distinct samples were accepted as being synthetic opal, as amounts of water. Thus, in the opinion of the stated by the manufacturer, entirely on the basis of authors, these substances should be designated their gemological properties. However, it has been suggested by one of the present authors and his coworkers that for non-single-crystal synthetics it is necessary to determine both the chemical com- ABOUT THE AUTHORS position (SiOT.*nH20for opal) and the phases Dr. Schmetzer is research associate a1 the Mineralogisch- present. Only when a man-made gem material is Petrographisches Inslitut der Universital Heidelberg, 0-6900 essentially, if not absolutely, identical in these Heidelberg, Federal Republic of Germany; Dr. Henn is re- search associate at the Deutsche Slillung Edelsteinlorschung, respects to the natural gemstone is it acceptable as 0-6580 Idar-Oberstein, Federal Republic of Germany. a synthetic counterpart. Acknowledgments: Financial support for this study was pro- A working definition for a distinction of true vided by grants from the Wirlschaftsministerium des Landes synthetic gem materials from imitations was pro- Rheinland-Ptalz, Federal Republic of Germany. posed by Nassau (1976, 1977).This proposal inclu- 0 1987 Gemological Institute of America

148 Notes and New Techniques GEMS & GEMOLOGY Fall 1987 Gigcue 1. These three exam- 7les of Inamori Created Opal ire produced by the Kyo- ;era Corp. of Kyoto, japan. The sample with the black. tody color weighs 3.96 ct 2nd measures 10 X 12 mm. ^hot0 0 Tino Hammid.

opal simulants rather than synthetic opals semiquantitative chemical investigations were (Schmetzer, 1983a, 1984). The present study was carried out using the energy-dispersive analytical conducted in an attempt to clarify the nomencla- system of an ARL-SEMQ electron microscope. ture for the man-made products of Kyocera Corp. Thermogravimetric analyses were undertaken be- that are known as Inamori Created Opals in the tween 20 and 1000° by means of a DuPont trade and have been represented as synthetics. therinobalance.

MATERIALS AND METHODS GEMOLOGICAL PROPERTIES Gemological properties were determined on sev- Visual appearance, refractive-index values, and eral samples of the Kyocera product; on the basis of specific-gravity values of the samples investigated these tests, play-of-color, and body color, four types are given in table 1. The refractive indices of the were identified (see table l), with two to four white and colorless (body color) samples were samples of each type selected for additional test- found to be close to the upper limit, but still ing. Structure was then determined by X-ray dif- within the range, for natural opals; the refractive fraction analyses with a Debye-Scherrer camera; indices of the black samples were found to be

Notes and New Techniques GEMS & GEMOLOGY Fall 1987 149 TABLE 1. Gemological properties of the man-made products of Kyocera Corp. that show play-of-color.

Sample Body color Play-of-color Refractive Specific types8 indexb gravityb A Colorless Green, blue, 1.459-1.460 2.20-2.22 violet 9 White Green, blue 1.460 2.21-2.22 violet C Black All spectral 1.463 2.23 colors D Black Green, blue, 1.466 violet

'Two to lour samples of each type were tested. ^Ranges are lor dillerenl samples 01 the respective type. slightly higher than the highest values determined is often referred to as a "lizard-skin, "chicken- to date for natural opals (Frondel, 1962; Deer et al., wire," or "honeycomb" structure (figure 3). Al- 1963; Troger, 1971; Phillips and Griffen, 1981).For though this pattern has been observed in a few all of the samples, the specific gravity determined natural opals (Scarratt, 1986), it is usually consid- slightly exceeds that of natural opals. ered characteristic of opal imitations. The refractive-index and specific-gravity All of these properties are consistent with the values for the Inamori products are distinctly data provided by Fryer et al. (1983)and are consid- higher than the values for the Gilson products, ered to be of diagnostic value. In most cases, a which lie in the range of about 1.440 and 2.04, combination of microscopic examination with respectively (e.g., Eppler, 1974; Scarratt, 1976). determination of refractive index and specific However, when viewed with a microscope, the gravity is sufficient to distinguish the Inamori Inamori products show features that also appear in product from natural opals. the Gilson material. Specifically, the Inamori cab- ochons reveal a diagnostic columnar structure that is evident when the samples are viewed at various Figure 3. This IZyocera opal imitation with angles to the curved surface of the cabochons black body color shows the niosaic-like pat- terns with distinct boundaries between differ- (figure2). Perpendicular to this columnar structure ent "grains," as well as the pattern referred to are mosaic-like patterns with distinct boundaries as "lizard-skin," "chicken-wire," or "honey- between different "grains." Each "grain" is divided comb" that is caused by the subdivision of into several subg grain^.^' In gemology, this pattern each color "grain." This pattern is considered characteristic of man-made opal. Magnified 40 x . Figure 2. The columnar structure of the color "grains" is evident in this Kyocera opal jmjta- I m - tion with black bodv dor. Magnified 20 X.

150 Notes and New Techniques GEMS & GEMOLOGY Fall 1987 COMPOSITION X-ray powder diffraction analyses of the samples selected for detailed examination revealed no dis- tinct pattern; that is, all four types are amorphous to X-rays. Chemical investigations indicate silica as the dominant component; no other major con- stituents were detected (as is also typical of most natural opal). Thermogravimetric analyses of all the samples showed no loss of weight up to 1000° (see figure 4, which also includes a typical dehy- dration curve for natural opal from Australia]. These results indicate that no water is present in TEMPERATURE (OC) any of the samples of Kyocera material that were tested. Figure 4. The absence of water in the Kyocera opal imitation is evident in this comparison of CONCLUSIONS the curve produced by thermogravimetric anal- The products of Kyocera Corp. that show play-of- ysis for a sample of the man-made material with black body color (a) with that of one pro- color consist of amorphous silica glass without any duced for a natural Australian opal of white admixtures of water. Comparison with the proper- body color fb). ties of lechatelierite, an amorphous and anhydrous form of silicon (R.I.= 1.46, S.G. =2.2] further sup- ports this conclusion. Because of the complete both natural opals and (as determined by the absence of water, these man-made materials are authors] the Kyocera opal imitations the play-of- not within the compositional range of natural color is caused by a closely packed array of uni- opals (see, e.g., Schmetzer, 1984). Consequently, formly sized amorphous silica spheres. In the the authors propose that these products of Kyocera opinion of the authors, a true synthetic must be Corp. should be designated opal simulants rather essentially identical in structure and composition than synthetic opals. It is not sufficient that in to its natural counterpart.

REFERENCES Scarratt K. (19761Notes on Gilson synthetic white opal. Journal Deer W.A., Howie R.A., Zussman J. (19631 Rock-Forming of Gemmology, Vol. 15, pp. 62-65. Minerals, Vol. 4, Framework Silicates. Longnian, London. Scarratt K. (19861 Notes from the laboratory-6. Journal of Eppler WF. (1974)synthetischer Alexandrit und synthetischer Gemn~ology,Vol. 20, pp. 93-97. Opal. Zeitschrift der Deiitschen Gemmologischen Ges- Schmetzer K. (1983a) Eine Untersuchung der opalisierenden ellschaft, Vol. 23, pp. 286-293. Syntheseprodukte von Gilson. Zeitschrift der Deutschen Frondel C. (1962) The System of Mineralovy, Vol. 3, Silica Gemmologischen Gesellschaft, Vol. 32, pp. 107-1 18. Minerals, 7th ed. 101111 Wiley & Sons, Ncw York. Schmetzer K. (1983b)Zur Natur der Lapis lazuli Imitation von Fryer C., Crowniiigshield R., Hurwit K.N., Kane R.E. (1983) Gilson. Zeitschrift der Deutschen Gemmologischen Ges- Gem trade lab notes. Gems el) Gemology, Vol. 19, pp. ellschaft, Vol. 32, pp. 107-1 18. 234-235. Schnietzer K. 11984) An investigation of the synthetic products Lind T Schmetzer K., Bank H. (19833) Zur Bestimmung of Gilson showing a play of colours. Journal of Gemmology, natiirlicher, behandelter und synthctischer Tiirkise sowie VO~.19, pp. 27-42. von Tiirkisimitationen. Zeitschrift der Deutschen Gem- Schmetzer K. (1985) The composition of the lapis lazuli mologischen Gesellschaft, Vol. 32, pp. 69-74. imitation of Gilson. Journal of Gemmology, Vol. 19, pp. Lind T, Schmetzer K., Bank H. (1983b) The identification of 571-578. turquoise by infrared spectroscopy and X-ray powder Schn~etzerK., Bank H. (19801 Eine Untersuchung der Turkis- diffraction. Gems is) Gemology, Vol. 19, pp. 164-168. synthese und Tiirkisimitation von Gilson. Zeitschrift der Nassau K. [I9761 How to define non-single-crystal synthetics. Deutschen Gemmologischen Gesellscliaft, Vol. 29, pp. Gems a) Gemology, Vol. 15, pp. 194-198. 152-154. Nassau K. (1977)Zur Bestin~mungvon "nicht-einkristallinen Schmetzer K., Bank H. (1981) An investigation of synthetic Synthesen." Zeitschrift cler Deutschen Genimologischen turquoise and the turquoise substitute of Gilson. lournal Gesellschaft, Vol. 26, pp. 19-23. of Gemmology, Vol. 17, pp. 386-389. Phillips W.R., Griffen D.L. (1981) Optical Mineralogy. The Troger W.E. (1971) Optische Bestimmung cier gesteinsbil- Nonopaque Minerals. W.H. Freeman and Co., San Fran- denden Minerale, Teil I Bestimmungstabellen. 4. Aufl. cisco. Schweizerbart, Stuttgart.

Notes and New Techniques GEMS & GEMOLOGY Fall 1987 151 MAN-MADE JEWELRY MALACHITE By V S. Balitsky, T M.Bublikova, S. L Sorolzjna, L. V. Balitskaya, and A. S. Shteinberg

Jewelry-quality synthetic malachite is now being variety of jewelry (Petrov et al., 1985).The authors n7anufactured in the LJSSR. The texture, structure, do not know if this material is being distributed and physical and physico-chemical properties of this outside the Soviet Union. synthetic malachite are reported. Three textural This article briefly describes the three most types have been identified: banded, silky, and bud- attractive varieties of the jewelry-quality syn- like. The malachite is composed of closely adjacent thetic malachite produced using the methods of spherulitic aggregates, the generation and growth of which are controlled by the crystallization the present authors (Balitslzy, 1983; Balitslzy et al., conditions. In chemistry, color, density, hardness, 1985): banded, silky, and bud-like. The authors optical properties, and X-ray diffraction, the then discuss the properties of the synthetic mal- synthetic malachite proved virtually identical to the achite and tests conducted to see how it can be natural material. Only in the tlier~~?ogrciniswere separated from the natural material. significant differences noted. Therefore, the man- nil~clenialachite holds much promise fo: use in stone MAJOR TYPES OF cutting and the jewelry trade. SYNTHETIC MALACHITE Banded. The banded synthetic malachite is very similar in appearance to the malachite from Zaire. Banding is formed by alternating parallel zones that range in color from light to very dark green, One of the major advances in gemstone synthesis almost black. The width of the zones varies from a over the past few years has been the production of few tenths of a millimeter to 3-4 mm. The zone jewelry-quality synthetic malachite. The syn- boundaries are straight, weakly undulating (see thesis was accomplished at three institutions in figure 2)) or intricately curved. The bulk of the the USSR at approximately the same time: sample is conlposed of closely adjoining spheruli- Leningrad State University (LGU; Petrov et al., tic aggregates of acicular or plate-like crystals. 1985); the All-Union Institute for the Synthesis of Both the spherulites and the crystals of which they Mineral Raw Materials (VNIISIMS), in the Minis- are made become larger as a result of geometric try of Geology of the USSR (Balitsky 1983; Tim- selection during growth. The samples with con- olzhina et al., 1983); and the Institute for Experi- trast banding display recurrent (inultilayer)gener- mental Mineralogy (IEM, USSR Academy of Sci- ation of spherulites at the boundaries of particular ences; Balitsky et a]., 1985). These institutions zones. Where the banding is less contrasting, the have devisedseveral original methods which allow development of new zones involves no interrup- nearly all textural varieties found in natural mal- tions in the formation of spherulites. Rather, in achite to be synthesized under chosen conditions this case the spherulite crystals acquire a sub- (figures 1-5). parallel orientation (figure 3). The methods currently used to synthesize malachite are based on its crystallization from aqueous solutions. Specimens produced thus far ------range from 0.5 kg to several kilograms. At the international exhibition held during the 27th In- ABOUT THE AUTHORS Dr Balilsky is head-and T M Bublikova, Dr Sorokina and ternational Geological Congress (Moscow, 1984)) L V Balitskaya are researchers-in the Laboratory lor Mineral vases cut from synthetic malachite pillars weigh- Synthesis at the Institute of Experimental Mineralogy USSR ing as much as 8 kg (and manufactured at the Academy of Sciences, Moscow Dr Shteinberg, a specialist in structural macrokinet~cs is a researcher at the Instilute of VNIISIMS) were on display. In fact, synthetic Chemical Physics, USSR Academy of Sciences, Moscow malachite is now being produced on a comnlercial Acknowledgments The authors are very grateful lo Mrs G B level. For example, the "Uralslzije samotsvety" Lakoza for the translation of this article and to Dr M A plant (at Sverdlovsk, in the Urals) both produces Bogomolov for the color photography synthetic malachite and mounts it in a wide iy 1987 Gemological Institute of America

152 Notes and New Techniques GEMS &. GEMOLOGY Fall 1987 Figure 1. These sanlples of synthetic jewelry-quality malachite, representing a mixture of banded and bud- like types, strongly mein- ble their natural counter- parts. The largest specimen ¥s11owrhere is 100 x 90 mm.

Figure 2. Undulating growth boundaries can be seen in this section of synthetic malachite with the banded texture. The cut is parallel to [he growth direction. Maximum length and width, 100 x 28 mm.

Silky. When cut parallel to the growth direction, banded synthetic malachite displays chatoyancy and appears silky. Individual crystals in the silky aggregates are 0.01-0.1 mm thick and several millimeters long. In some samples with complex Figure 3. This finely banded sample of synthetic banding, the chatoyancy is particularly attractive. malachite shows the many-tier nucleation of Distinct areas appear light in cuts parallel to the spherulites. The cut is parallel to the growth di- crystal elongation and almost black in cuts per- rection. Magnified 30 x .

Notes and New Techniques GEMS & GEMOLOGY Fall 1987 153 particular spherulites and develop either a radiated or a concentric zonal structure. In the former type, the crystals, in the buds are arranged radially relative to the center of the spherulite nucleus. On cut surfaces, such buds display a gradual color change from almost black at the center to light green toward the edges. The coloration depends on the pattern of relative orientation of the crystal axis and the cut plane. In addition, the tones and intensity of the color can vary with the viewing angle or with the angle of light incidence. In the second type of structure, the buds are composed of concentric zones that vary in color from light to dark green (figures4 and 5).Each zone has the spherulitic structure, the spherulites being 0.01-3 mm in size. The zones composed of small spherulites are lighter than those composed of Figure 4. A bud-like texture is evident in this large ones. Every new zone normally gives rise to a sample of synthetic malachite, which is cut parallel to the growth direction. Maximum new generation of spherulites, but occasionally length and width, 30 x 12 mm. earlier spherulites are inherited by the later ones. In addition to the above textural types, several intermediate varieties of synthetic malachite- representing a mixture of two or all three of these types-are also possible (again, see figure 1).

PROPERTIES OF SYNTHETIC MALACHITE The chemical composition (table 1) and principal physical and physico-chemical properties (table 2) of the scores of synthetic malachite samples exam- ined for this study were compared with the data available on natural samples from the Urals, Ka-

TABLE 1. Mean chemical compositions for natural and Figure 5. In this close-up view of a sample of synthetic malachi1e.a bud-like synthetic malachite, the concentric Natural (locality) Synthetic (rnfr.) zones of which the buds arc comprised are Components - readily evident. The cut is perpendicular to the (wt.%) Kazakhstan lEMb VNIISIMS growth direction. The buds range in diameter CuO 71.77 70.22 71.90 from 5 to 10 mrn. Mgo 0.001 0.01 7 ndc CaO 0.003 0.014 nd H20 8.52 9.31 - pendicular to it. The silky material is, however, the co2 19.65 19.94 - H20 + COP - - 28.35 least desirable for jewelry use. -- -- Total 99.94 99.50 100.25 Bud-like. The bud-like synthetic malachite is of a higher jewelry quality than the banded material 'At least 20 samples ol each type were analyzed All analyses were performed by the authors using a combination of wet (see figure 4). It is similar in appearance to the chemical and spectrophotometr~cmethods. famous Ural malachite. Individual buds in syn- "For the samples Irom Kazakhstan and /EM, Fed, SiO,, TiO,, Al2Og, and Fe,03 were also determined but not detected thetic specimens range from 2-5 to 10-15 mm end = not determined across. They are formed as a result of the growth of

154 Notes and New Techniques GEMS & GEMOLOGY Fall 1987 TABLE 2. Gemological properties of natural and synthetic rnala~hite.~

Natural (locality) Synthetic (rnfr.) - -- Property Zaire Kazakhstan IEM LG U VNIISIMS

Color Light Green Light Almost black Almost green green to light black to dark to dark green with to light green green pale bluish green tint

Refractive indices a 1.907 1.909 1.908 1.907 1.911 I3 1.874 1.875 1.876 1.875 1.877 7 1.653 1.655 1.657 1 654 1.658 Density, 4.0 4.1 4.0 3.95 3.90 gIcm3 Hardness 4.4 4.2 4.2 4.5 3.5 (Mohs scale) Endothermal 34 2 340 270, 272, 275, effect, 'C 300 301 305 (peak center)

-A/ least five samples of each type were examined

zakhstan, and Zaire (Grigorjev, 1953; Vertushlzov, 1975).The chemical composition of the synthetic malachite produced by IEM and VNIISIMS proved almost. identical to that of the natural malachite found at Kazakhstan (table 1)) although some natural malachite has a high cobalt and nickel content (Deliens et al., 1973; Tarte and Deliens, 1974). Both the natural and the synthetic mal- achite examined contained minor amounts (hull- dredths and thousandths of a percent) of impuri- ties such as zinc, iron, silica, sulfur, calcium, and phosphorus. These impurities had only a very slight effect on the refractive indices of the syn- thetic malachite, which average a = 1.909 Â 0.002, = 1.876 Â 0.001, -y = 1.656 Â 0.002. The synthetic malachite was found to vary in density (asdetermined hydrostatically] from3.9 to 4.0 gIcn~3,and in hardness from 3.5 to 4.5 on the Mohs scale. The hardness is a little lower along the crystal elongation than perpendicular to it. X-ray diffraction analysis of all the types of synthetic malachite produced thus far (DRON-2 diffractometer, CoKn radiation, filter Fe) detected no differences from natural malachite (figure 6).

Figure 6. No significant differences were observed in the X-ray powder diffraction curves t of natural and synthetic malachite. Natural 24 22 20 18 16 14 12 10 8 6 4 samples: I ÑKazakhstan 2-Zaire. Synthetic DEGREES 9 samples: 3 - IEM, 4 - LGU, 5 - VNIISIMS.

Notes and New Techniques GEMS & GEMOLOGY Fall 1987 155 Figure 7. Examination of the in/r(ired spectra of natural and synthetic malachite in the regions A = 200-2000 ci71 - arid B = 3000-4000 cm - 1 revealed no significant differences either. Nat ural samples: 1 - Kazakhstan, 2 - Zaire. Synthetic samples: 3 - IEM, 4- LGU, 5- VNIISIMS.

WAVENUMBER (cm - 1) -

As reported in 1983 by Tin~okhinaet al., no differences in infrared spectra have been found for synthetic and natural malachite [either in the regions of stretching vibrations of Cu-0 (400-600 cm-I), C-0 (1000-1 100 and 1350-1550 cm- I), and OH- groups (3315-3410 cm- I), or in the deformation vibration region 0-C-0 (700-900 cm-I]]. Figure 7 shows characteristic infrared spectra in the regions 200-2000 cm -1 and 3000-4000 cm - 1 for different samples of natural and synthetic malachite. Some difference between synthetic and natu- ral malachite can be seen in the pattern of curves 1 L- produced by differential thermal analysis and 220 260 300 340 380 420 TEMPERATURE ('C) thermogravimetry (figure 8). Five samples of each were tested. As illustrated in figure 8, dehydration Figure 8. Only the thermogmins revealed a and decarbonation of natural malachite take place clear distinction between the natural and syn- at one stage marked by a profound endothermal thetic malachite examined. Natural malachite effect in the 310'-390° range (thepeak centers at from Kazakhstari (1) and the Urals (2);syn- 340'-345OC) and at a weight loss of 27.5-28 thetic malachite with the banded (3) and bud- mass %. In the synthetic malachite (the banded like (4) textures.

156 Notes and New Techniques GEMS & GEMOLOGY Fall 1987 Figure 9. AH of these pol- ished samples of synthetic n~alcicl~lteshow potential for use in jewelry, carving, or inlay. The ccibochons range from 15 to 32 mm.

and bud-like varieties), the endothermal effect is in the USSR is virtually a con~pleteanalogue of displayed in a lower region, 230'-340°C and the natural jewe1ry;quality malachite with respect to weight,lo,ss is 29-30 mass %. The thermograins of physical appearance, chemistry, texture, struc- all the synthetic malachite tested always showed ture, and principal physical properties (again, see two weak minima (the first peak center is at table 2). Thus far, the only method that has proved 270'-27S°C the second is at 300°-30S°CThe effective in separating the natural from the syn- cause of these differences has not yet been deter- thetic material is differential thermal analysis. mined. However, it does not appear that these However, the fact that this test is destructive differences have affected the mineral structure in makes it impractical for gemological purposes. It any way. appears, therefore, that there are unlimited possi- bilities for the man-made malachite to be used in CONCLUSION stone cutting and for inlay, carvings, and cab- The synthetic malachite currently being produced ochons in the jewelry trade (figure 9).

REFERENCES Petrov TG., Zhogoleva VYu., Tseitlin Ya.E., Moshliin S.V, Balitsky VS. (1983)Experimental mineralogy and synthesis of Nardov A.V, Gliliin A.E., Khatelishvily C.V, Domnina single crystals (in Russian). Sovetsknyn Cenlogiya, No. 10, M.I., Zhnrba VN., Efimova E.F. (1985) Crystallogenctic pp. 101-108. characteristics of synthetic jewelry malachite [in Rus- Balitsky VS., Bubliliova T.M., Sorokina S.L., Balitskaya L.V, sian]. Sixth All-Union Conference on Crystal Growth, Shtcinberg A.S. (19851 Synthetic and natural malachite Abstract Papers, Ercvan, Vol. 2, pp. 156-157. [investigation and comparison of principal properties; in Tarte P., Dcliens M. 119741 Caracterisation des malachites Russian). AllUnion Conference on the Theory and Meth- nicliclif~resct cobaltiferes par lour spectre infrarougc. odology of Mi~~eralogy,Absiract Papers, Syktyvkar, Vol. 2, Bulletin de 10 Sociite Koyalu des Sciences de Liige, Vol. 43, pp. 25-27. No.1-~2,pp. 96- 105. Dcliens M., Oosterbosch R., Verbecli T (1973) Les malachites Timolihina I.V, Balitsky VS., Shaposhnil~ovA.A., Bublikova cobaltif6res du Shaba meridional (Zaire). Bulletin dc In TM., Kovalenko VS., Akhmetova C.L., Dubuvsliy A.B., Socidi Fraiifaise lie Minetiilos,iu el Cristallograpbie, Vol. Andrceva T.G., Shironina TV (1983) Physical-chemical 96, No. 6, pp. 371-377. studies of synthetic malachite (in Russian). Doldady Grigorjcv D.P. (19.531 On the genesis of syngenctic or meta- Akadernii Nank SSSR, Vol. 270, No. 5, pp. 11 17-1 119. colloidal colloform mineral aggregates [in Russian). Vert~ishkovG.N. (19751 The Chun~esl~evskoedeposit in the Ziipiski Vsesojuznogo ~Vlinerulogicl~esKogo Obshcl~estvn, Urals [in Russian). Trudy Sverdlovskogo Cornogo Insti- Ser. 2, Part 83, No. 1, pp. 7-21. ttita, No. 48, pp. 3-26.

Notes and New Techniques GEMS &. GEMOLOGY Fall 1987 157 INAMORI SYNTHETIC CAT'S-EYE ALEXANDRITE By Robert E. Kane

The world's first commercially available synthetic impurity of Cr3-'-. A conspicuous change of color cat's-eye alexandrite chrysoberyl is now being manu- from an intense bluish green to a deep "raspberry" factured and marketed by the Kyocera Corporation in (purplish)red is the most desirable for alexandrite. Kyoto, Japan. 1Zyocera markets synthetic gemstones The flux growth of nonphenomenal chrysoberyl in the United States under the trade name "Inamori dates back to the latter half of the 19th century. Created." This article reports on a detailed gemologi- From 1845 on, Ebelman used borate fluxes to cal examination of this new synthetic cat's-eye alax- synthesize very small crystals of chrysoberyl. andrite. Although most of the gemological properties of this new synthetic overlap those of natural cat's- Later Deville and Caron, and Hautefeuille and eye alexandrite, it can be identified by its unique in- Perrey, also reported similar success with chrys- ternal characteristics and its unusual fluorescence to oberyl synthesis (Nassau, 1980).Nassau also noted short-wave ultraviolet radiation. that in recent years experiments have been con- ducted with the more common lithiun~molybdate and lead oxide-lead fluoride-boron oxide flux combinations, but only small crystals have been produced. He also cites reports of the use of the In late January 1987, the Inamori Jewelry Division Verneuil process to synthesize chrysoberyl or of Kyocera International, Inc., San Diego, Califor- alexandrite-crystal boules. nia, gave GIA two synthetic cat's-eye alexandrite Synthetic chrysoberyl containing only chro- chrysoberyls for study. Kyocera reported that these mium as a trace elen~ent,usually at the 0.05% two oval double cabochons (3.27 and 3.3 1 ct) were level or less (which results in pale color and a very representative of the new synthetic cat's-eye alex- weak alexandrite effect), provides a useful laser andrite being manufactured and cut in their highly crystal. Laser rods up to 2.5 cm in diameter and 15 automated synthetics facility in Kyoto, Japan. cm long (1 in. x 6 in.) are being grown by the (figure 1). Czochralslzi pulling technique at the Allied Chem- This new synthetic cat's-eye alexandrite was ical Corp. of Morris Township, New Jersey (Morris first marketed in Japan set in jewelry in early and Cline, 1976).Faceted stones cut from synthetic September 1986, and has just been released in the alexandrite grown by the Czochralslzi method at United States as loose stones as well as in jewelry. Allied Signal Corp. (formerlyAllied Chemical) are As of June 1987, Kyocera had produced only 250 ct now commercially available in the trade. The of this material for jewelry purposes. The stones hydrothermal growth of synthetic chrysoberyl, currently available range in weight from slightly but apparently not of alexandrite, has been re- under 1 ct to 7.5 ct (K. Talzada, pers. comm., 1987). ported in a series of Czechoslovalziai~patents by They are marketed in the U.S. under the trade D. Rykl and J. Bauer (Nassau, 1980). name "Inamori Created," as are Kyocera's other synthetic gems. In preparing this article, a total of 13 cabochon-cut Inamori synthetic cat's-eye alex- andrites, ranging in weight from 1.04 to 3.3 1 ct, ACKNOWLEDGMENTS: The author thanks Kyocera Corp., of were subjected to several gemological tests, includ- Kyoto, Japan, and Mr. Ken Takada, of the Inamori Jewelry Divi- ing detailed microscopic study. The results are sion of Kyocera International,,Inc., San Diego, California, for reported below. A brief history of chrysoberyl their cooperation in supplying information and material for ex- amination. Ms. Yoshiko Doi, of the Association of Japan Gem synthesis is also provided. Trust, Tokyo, Japan, also kindly loaned a sample synthetic. GIA's Course Development Department supplied the line illus- HISTORY OF trations in figure 2. Dr. Emmanuel Fritsch, of the GIA Research Department, did the spectrophotometer work. Mr. Shane Mc- CHRYSOBERYL SYNTHESIS Clure, of the GIA Gem Trade Laboratory in Los Angeles, pro- Alexandrite is the color-change variety of chrys- vided helpful suggestions. oberyl, the beryllium aluminate, BeA1204,with an 0 1987 Gemofogical Institute of America

158 Notes and New Techniques GEMS & GEMOLOGY Fall 1987 Faceted synthetic alexandrite has been pro- duced and marketed sporadically since 1973 by Creative Crystals of San Ramon, California, under the trade name Alexandria-Created Alexandrite (Cline and Patterson, 1975). Although both flux and melt techniques are covered in this patent, the inclusions present in the synthetic alexandrite comn~erciallyavailable from Creative Crystals indicate that this material is definitely flux-grown. In 1974, Creative Crystals experimentally synthe- sized cat's-eye chrysoberyl (notalexandrite) by the flux method; however, this product was never placed on the market (D. Patterson, pers. comm., 1987). Faceted synthetic alexandrite has been com- mercially available from Kyocera International since 1975 (K. Taliada, pers. comin., 1987). This material does not show any characteristics of flux growth and is probably grown by a melt process, specifically the Czochralski pulling method. Con- Figure 1. This Inmori synthetic cat's-eye dex- firmation of this is provided by a U.S. patent andrite appears dark purple-red in incandescent light. Photo 0 Tino Hammid. assigned to Kyoto Ceramic Co. by Machida and Yoshihara (1980))in which the primary emphasis andrites do not show any microscopic characteris- is a description of synthesizing alexandrite by a tics of fluxgrowth, leads to the conclusion that this direct melting method: the Czochralslii (rotational new product is grown by the Czochralslii method. pull-up) technique. On 'July 15, 1983, Women's Wear Daily re- GEMOLOGICAL PROPERTIES ported that the Sumitomo Cement Company's Thirteen cabochon-cut Inamori synthetic cat's-eye central research laboratory, based in Funabashi alexandrites were closely examined and submitted City, Japan, had succeeded in synthesizing cat's- to a variety of gemological tests. The results are eye alexandrite. Sun~itomofiled for worldwide reported below and summarized in table 1. patents for synthesizing this material with a melt method that uses the floating-zone technique Visual Appearance. A distinct color change was (K.Taliada, pers. comm., 1987).The growth process observed in all of the samples in fluorescent is followed by spontaneous cooling to room tem- illumination (or natural sunlight) as compared to perature and a special heat-treatment process. incandescent illumination. When the stones were In September 1983, independent of Sumitomo, viewed with a single overhead light source, a broad Kyocera began experimentation on the synthesis of eye of moderate intensity was noted in each. When cat's-eye alexandrite (K. Taliada, pers. comm., viewed with a Verilux fluorescent light source, the 1987). This research led to the eventual commer- synthetic cat's-eye alexandrites appear dark gray- cial marketing of this new synthetic. In a U.S. ishgreen with a slightly purplish overtone. The eye patent by Uji and Nakata (1986) assigned to the exhibits a slightly greenish white-blue color. Kyocera Corp., the synthesis of single-crystal cat's- There is an overall dull, "oily" appearance. When eye chrysoberyl (not alexandrite) is described. The viewed with an incandescent light source (figure primary emphasis of the patent is on several 1)) the same stones changed to a dark purple-red examples whereby the Czochralski method is with a bluish white eye, again with an overall dull, used. The patent also mentions two different "oily" appearance. This "oily" appearance affected examples of synthesizing an "olive-green" and a the transparency slightly in both types of illu- brown cat's-eye chrysoberyl (not alexandrite) by mination. When viewed with the unaided eye and means of a lithium molybdate flux. However, overhead illumination, as well as with transmitted information contained in this patent, in addition to illumination, these synthetics appeared to be com- the fact that the Inamori synthetic cat's-eye alex- pletely free of inclusions.

Notes and New Techniques GEMS & GEMOLOGY Fall 1987 159 refractive-index values (1.745-1.755, obtained by TABLE 1. The gemological properties of the Inamori the spot method), specific-gravity values (3.73 ? synthetic cat's-eye alexandrites. 0.02), trichroism (purple-red,brownish orange, and Properties that overlap those of gray-green),and a bright red reaction to the Chelsea natural cat's-eye alexandrites color filter that are all essentially consistent with Color Moderate to distinct color change from dark grayish green, with a slight purplish the corresponding properties in natural cat's-eye overtone, and a slightly greenish white-blue alexandrite. The spectra observed with a GIA Gem eye under fluorescent lighting; to a dark Instruments spectroscope unit are the same as purple-red, with a bluish white eye when viewed with incandescent light those for alexandrite (natural and synthetic) de- Visual Transparent with an overall hazy, "oily" scribed in Liddicoat (1981, p. 191)and shown here appearance to appearance in both lighting conditions; no in figure 2. These features were confirmed by the unaided eye inclusions are visible to the unaided eye spectrophotometry. Refractive index Spot readings of 1.745-1.755 Trichroism Strongly distinct colors of purple-red, Transmission Luminescence. When the synthetic brownish orange, and gray-green cat's-eye alexandrites were placed over the strong Color filter Bright red reaction light source from the opening of the iris diaphragm Specific gravity 3.73  0.02; estimated with heavy liquids on the spectroscope unit, they all displayed a very Absorption Absorption lines at 680.5, 678.5, 665, 655, strong greenish white transmission luminescence spectrums 645, 472. and sometimes at 468 nm (very (in some viewing positions a slight pink cast was (400-700 nm) weak); broad absorption blocking out all of seen; see figure 3, left). In fact, the transmission the violet and some of the blue, and portions of the yellow-green to orange areas of the luminescence was so strong that it was visible even visible spectrum. Spectrum will vary in sunlight, or any artificial light. This transmis- depending on viewing position and which sion luminescence is the cause of the overall dull, rays are isolated. "oily" appearance seen when the stones are viewed -lvQ>a;?È4 Key Identifying properties - A- ww with the unaided eye, as discussed above. fluorescence Although natural cat's-eye alexandrites may Long-wave Moderate red (overlaps natural, not exhibit a similar transmission, it is generally not diagnostic) u. Short-wave Weak, opaque, chalky yellow fluorescence as strong and has a slightly different appearance. In that appears to be confined near the contrast, many natural as well as synthetic alex- r surface; careful examination reveals an andrites (not chatoyant) will exhibit a strong red underlying weak red-orange fluorescence. transmission (see figure 3, right). Inclusions Parallel, straight-appearing and undulating color-zoned growth features; and - 7- nondescript white-appearing, minute w.Figure 2. The absorption spectra for Inamori particles specifically oriented in parallel ~uwwcA planes (visible only with fiber-optic synthetic cat's-eye alexandrite, as observed on illumination), which ~iverise to the a hand-held type of spectroscope at room tem- chatoyancy. With the iris diaphragm par~ially, perature. The upper dr(iwing shows the spec- closed (mr darkfield illumination at 25 xu trum seen in the red direction, and the lower create a shadowing effect, the unevenly spaced parallel growth features becornern shows the spectrum seen in the green direction. more evident and reveal themselves as Spectral colors (ire approximate. undulating rather than straigh" I

'As observed through a hand-held type of spectroscope

Interestingly, when the cabochons were viewed under a strong, single incandescent light source down the long direction, asterism was observed. The two additional rays were weaker than the chatoyant band. This behavior would not be expected in natural cat's-eye alexandrites. Physical and Optical Properties. Testing of the Inamori synthetic cat's-eye alexandrites revealed

160 Notes and New Techniques GEMS & GEMOLOGY Fall 1987 Figure 3. Transmission luminescence as seen over the strong light source from the opening of t11e iris diaphragm on the spectroscope unit. Left, Inamori synthetic cat's-eye alexandrite; right, natural alex- andrite from Brazil. Photos by Shone McClzire.

Fluorescence. When the synthetic cat's-eye alex- U.V radiation would not be expected in a natural andrites were exposed to long-wave (366 nin) cat's-eye alexandrite, and therefore provides the ultraviolet radiation, a moderate red fluorescence gemologist with an excellent indication that the was observed. This reaction to long-wave U.V piece is synthetic. radiation' is also seen in natural cat's-eye alex- andrites. When the samples were exposed to short- Microscopic Study. All of the samples were care- wave (254nm) U.V radiation (in a dark room, with fully exanlined with a standard gemological binoc- the synthetic stone lying 011 a black pad raised to ular microscope; darlzfield, fiber-optic, transmit- within a few inches of the U.V source), an unusual ted, and polarized illumination were all used. reaction was observed. The cabochons exhibited a When the cabochons were examined with weak, opaque, chalky yellow fluorescence that darlzfield illumination, parallel striations were appears to be confined near the surface. Careful seen oriented perpendicular to the length of the examination revealed an underlying red-orange cabochon. However, it was difficult to discern the fluorescence. This unusual reaction to short-wave precise nature of these striations because viewing

Figure 4. With the built-in iris diaphragm on the Gem- ofite microscope stage par- tially closed (over darlzfield 1illumination) to create a shadowing effect in this cabochon-cut Inamori syn- thetic cat's-eye alexandrite, the unevenly spaced parallel growth features become more evident and reveal themselves as undulating rather than straight. Mag- nified 25 x .

Notes and New Techniques GEMS & GEMOLOGY Fall 1987 161 rise to the chatoyancy (figure 5). No other distinc- tive features were seen with transmitted or po- larized illumination. None of the inclusions re- sembled natural inclusions. Natural cat's-eye chrysoberyls (non-color change, as well as alexandrite) always contain ultra-fine parallel growth tubes or needles that are oriented very close together and give rise to the cat's-eye effect when the stones are cut en cab- ochon. These inclusions are quite different in appearance from those observed in the Inamori synthetic cat's-eye alexandrites. Natural cat's-eye chrysoberyls also are frequently host to solid crystal inclusions of mica, quartz, apatite, and actinolite as well as other minerals. In addition, Figure 5. Oblique illumination created with a two- and three-phase fluid inclusions, containing fiber-optic light unit reveals the nondescript, both water and carbon dioxide, are commonly white-appearing, minute particles -specifically seen. Also typical of natural cat's-eye chrysoberyls oriented in parallel planes (in association with are strong, highly visible growth features; they the undulating striations shown in figure 4)- may be parallel, singular, straight, angular, and that give rise to the chatoyancy in this 1namori synthetic cut's-eye alexandrite. The larger white irregular. The Inamori synthetic cat's-eye alex- spots are surface features on the. stone. andrites examined to date do not contain any of Magnified 45 x . these internal features. IDENTIFICATION AND CONCLUSION was obstructed by the typical "halo" seen in The Inamori synthetic cat's-eye alexandrites transparent, highly polished double cabochons. closely resemble their natural counterparts in Partially closing the built-in iris diaphragm (over visual appearance, and most of their physical and darlzfield illumination)on the microscope stage, to optical properties overlap those of natural cat's-eye create a shadowing effect, revealed that the un- alexandrites. The key identifying characteristics evenly spaced parallel growth features are undulat- of the new Inamori synthetic are: (1)the undulat- ing rather than straight (seefigure 4).Such features ing growth features seen with the microscope would not be expected in natural cat's-eye alex- when shadowing and darlzfield illumination are andrites. Fiber-optic illumination revealed non- used, and the white particles seen when fiber-optic descript white-appearing minute particles that are illumination is used in conjunction with magnifi- specifically oriented in parallel planes (in associa- cation; and (2)the unusual fluorescence seen with tion with the above-mentioned striations),and give short-wave ultraviolet radiation.

REFERENCES Cline C.F., Patterson D.A. (1975)Synthetic crystal and method Morris R.C., Cline C.F. (1976) Chromium doped beryllium of making same. United States patent 3,912,521, filed aluminate lasers. United States patent 3,997,853, filed April 30, 1973, issued October 14, 1975. November 29, 1974, issued December 14, 1976. Liddicoat R.T. Jr. (1981)Handbook of Gem Identification, 1lth Nassau K. (1980) Gems Made by Man. Chilton Book Co., ed. Gemological Institute of America, Santa Monica, CA. Radnor, PA. Machida H.,Yoshihiira Y. (1980) Synthetic single crystal for Uji M. I., Nakata R. (1986) Chrysobcryl cat's-eye synthetic alexandrite gem. United States patent 4,240,834, filed single crystal. United States patent 4,621,065, filed Sep- September 14, 1979, issued December 23, 1980. tember 21, 1984, issued November 4, 1986.

162 Notes and New Techniques GEMS & GEMOLOGY Fall 1987 Back Issues of

kitedquantities of the following back issues of Fall I! Winter 1983 Summer 1984 Gems & ~emolog~are still available. Gems "'""nology I Spring 1981 Summer 1985 Zabargad: The Ancient Peridot Island in the Red Sea Pearl Fashion Through the Ages ~ubiczirconia'An Update Russian Flux-Grown Synthetic Emeralds A Simple Approach to Detecting Diamond Simulants Gem Pegmatites of Minas Gerais, Brazil: The The Hidden Beauty of Amber: New Light on an Old Tourmalines of the Governador Valadares District Subject The Eyepiece Pointer: A Useful Microscope Artificially Induced Color in Amethyst-Citrine Quartz Accessory Winter 1981 Lapis-Lazuli from Sar-e-Sang, Badakhshan, Fall 1985 Afghanistan Sapphires from Australia Gem Garnets in the Red-to-Violet Color Range Pink Diamonds from Australia San Carlos Peridot The Biron Hydrothermal Synthetic Emerald Spring 1985 - - - Irradiated Topaz and Radioactivity Nonfading Maxixe-Type Beryl? Winter 1985 A Status Report on Gemstones from Afghanistan The Cutting Properties of Kunzite A Proposed New Classification for Gem-Quality Spring 1983 Garnets ¥ Art Deco: The Period, the Jewelry Amethystine Chalcedony The Capao Topaz Deposit, Ouro Preto, Minas Gerais, The Pearl in the Chicken: Pearl Recipes in Papyrus Brazil Holmiensis Harry Winston: A Story Told in Diamonds Padparadscha: What's in a Name? Spring 1986 A New Classification for Red-to-Violet Garnets A Survey of the Gemstone Resources of China A Response to "A New Classification for Red-to- The Changma Diamond District, Mengyin, Shandong Violet Garnets" Province, China Fall 1983 Gemstone Carving in China: Winds of Change The Ramaura Synthetic Ruby A Gemological Study of Turquoise in China The Oil Treatment of Emeralds in Bogota, Colombia The Gemological Characteristics of Chinese Peridot A Computer Program for Gem Identification The Sapphires of Mingxi, Fujian Province, China The Identification of Turquoise by Infrared Summer 1986 Spectroscopy and X-ray Powder Diffraction The Coscuez Mine: A Major Source of Colombian Winter 1983 Emeralds Engraved Gems: A Historical Perspective The Elahera Gem Field in Central Sri Lanka Gem Andradite Garnets Some Unusual Sillimanite Cat's-Eyes The Rubies of Burma: A Review of the Mogok Stone An Examination of Four Important Gems Tract Green Glass Made of Mount Saint Helens Ash? Induced Fingerprints Cobalt Glass as a Lapis-Lazuli Imitation Fall 1986 Summer 1984 A Simple Procedure to Separate Natural from Gem-Bearing Pegmatites' A Review Synthetic Amethyst on the Basis of Twinning Summer 1988 Fall 1988 Gem Pegmatites of Minas Gerais, Brazil: Exploration, Pink Topaz from Pakistan Carbon Dioxide Fluid Inclusions as Proof of Natural- Ge~eindtogy Occurrence, and Aquamarine Deposits The First-Order Red Compensator: An Effective Colored Corundum Gemological Tool Contributions to a History of Gemology: Specific Gravity-Origins and Development of the Fall 1984 Hydrostatic Method Freshwater Pearls of North America Colombage-Ara Scheelite The Chemical Distinction of Natural from Synthetic Emeralds Winter 1986 Identifying Gem-Quality Synthetic Diamonds: An The Gemological Properties of the Sumitomo Gem- Update Quality Synthetic Yellow Diamonds .- Inclusions in Taaffeites from Sri Lanka Art Nouveau: Jewels and Jewelers Magnetic Properties of Gem-Quality Synthetic Contemporary Intarsia: The Medvedev ~pproachto Diamonds Gem Inlay Winter 1988 Winter 1984 Also available Natural Rubies with Glass-Filled Cavities Complete your back Pyrope-Spessartine Garnets with Unusual Color Spring 1987 -1 Behavior ''Modern" Jewelry: Retro to Abstract issues of Gem-Quality Red Beryl from the Wah Wah Infrared Spectroscopy in Gem Identification Mountains, Utah A Study of the General Electric Synthetic Jadeite Gems & Gemology An Extraordinary Calcite Gemstone A New Gem Material from Greenland: Iridescent NOW! Green Opal from East Africa Orlhoamphibole Spring 1985 Summer 1987 Singll $ 7.00 ea, U.S. Gem Pegmatites of Minas Gerais, Brazil: The Gemstone Durability: Design to Display Issues $ 9.00 ea. Elsewhere (surf Tourmalines of the Araquai Districts The Occurrence and Gemological Properties of $10.50 ea. Elsewhere (air) Sapphire from the Mercaderes-Rio Mayo Area, Wessels Mine Sugilite Cauca, Colombia Three Notable Fancy-Color Diamonds: Purplish Complete $22.50 ea. U.S. Altering the Color of Topaz Red, Purple-Pink, and Reddish Purple Volumes:' $27.50 ea. Elsewhere (surf A Preliminary Report on the New Lechleitner The Separation of Natural from Synthetic Emeralds 1985 full set $34.50 ea. Elsewhere (air) Synthetic Ruby and Synthetic Blue Sapphire by Infrared Spectroscopy ORDER 1986 full set Interesting Red Tourmaline from Zambia The Rutilated Topaz Misnomer 1985 and $39.50 ea. U.S. 1986 set $49.50 ea. Elsewhere (surf.) NOW! $60.50 ea. Elsewhere (air) '10% discount lor GIA Alumni Association members TO ORDER: Call: toll free (800) 421-7250, ext. 201 OR WRITE: GIA, 1660 Stewart Street, Santa Monica, CA 90404, Attn: G&G EDITOR C. W. Fryer GIA, Santa Monica CONTRIBUTING EDITORS Robert Crowningshield LAB NOTES "em Trade Laboratory, New York Karin N. Hurwit Gem Trade Laboratory, Los Angeles Robert E. Kane Gem Trade Laboratory, Los Angeles

Brazilian ALEXANDRITE color change and a well-defined, but not exceptional, chatoyancy. Appar- All three locations of the CIA Gem ently the silk responsible for the Trade Laboratory have recently had chatoyancy is not fine enough to the opportunity to examine a num- create a top-quality cat's-eye effect. ber of cut alexandrites from the new The largest of the cat's-eye stones we find in Minas Gerais, Brazil. The were shown was approxin~atelyone stones examined to date have ranged carat. Shane McClrrre in size from 0.20 to 6 ct. While we do -- not know the extent of this deposit, there have been reports of substan- Figure 1. The dark green stains tial quantities of rough. The color DIAMOND change of most of the stones exam- seen at 40x magnification on ined thus far is reminiscent of fine Highly Radioactive this 2.67-ct green diamond in- Russian alexandrites: from green to Green Diamond dicate that the stone has been bluish green in day (or fluorescent) Green diamonds are a continuing radium treated. light to purple to reddish purple in problem for jewelers and gemolo- incandescent light. Photos in the gists. For many stones, it is difficult, Gem News section of the Summer if not impossible, to determine 1987 issue of Gems s) Gemology whether the color has been produced show this change very nicely. artificially by irradiation or is natu- The properties of these stones ral, However, radium-treated dia- are consistent with the published monds, though rarely seen in recent properties for alexandrite. Those the years, are readily detectable with lab has seen show a very strong red relatively simple tests. Dark green transmission and a weak red ultra- stains are usually visible on the facet violet fluorescence. Inclusions range surfaces of the stone when examined from typical "fingerprints" and large with magnification. In addition, Figure 2. The radioactivity of transparent and white crystals to these stones are weakly to moder- the 2.67-ct green diamond pro- groups of bright stringers of tiny ately radioactive and can therefore be duced this autoradiograph in inclusions, very similar to those detected by a Geiger counter, Ra- only one hour. found in some flux-grown synthetic dium-treated diamonds will also pro- rubies. These are best seen with fiber duce an autoradiograph (i.e., take unusually high level of radioactivity, optic illumination. Some of the their own photo from the radiation 70 millirems per hour; the radiation stones are very clean. they give off] when placed in contact rate for radium-treated diamonds we The lab has also examined a few with a piece of photographic film for observed in the past usually ranged cat's-eye alexandrites from the same a period of time. from I to 10 n~illiremsper hour. locality. Most exhibit the same fine A 2.67-ct green marquise-shape Whereas we normally must leave a brilliant-cut diamond that was re- radioactive diamond on the film -. cently examined by the New York overnight to get an image, this stone Editor's Note: The initials at the end of each laboratory displayed small dark produced an autoradiograph (see fig- item identify the contributing editor who provided that item. green color concentrations when lire 2) in only an hour! One possible viewed with magnification (figure 1). explanation is that this stone was 63 1987 Gemological Institute dl America The radiation detector indicated an only recently subjected to radium

164 Gem Trade Lab Notes GEMS & GEMOLOGY Fall 1987 irradiation. The last stone we re- ported with a relatively high level of radioactivity (40 millirems per hour) was noted on page 304 of the Summer 1968 issue of Gems &> Gemology. Although there are no official guidelines for the use of radioactive stones in jewelry, we strongly reconl- mend :igainst it because of the poten- tial health hazard to the wearer. David Hargett

Treated Yellow Diamond with Cape Lines A 1.09-ct yellow round brilliant-cut diamond (figure 3) was submitted to the New Yorlz laboratory for cleter- mination of the origin of the color, which at first glance appeared to be in or near the fancy intense yellow range. This stone fluoresced a weak, somewhat chalky greenish yellow to long-wave ultraviolet radiation and had a similar, but weaker, reaction to short-wave U.V radiation. When ex- amined with our standard spectro- scope unit, the stone displayed a strong Cape series of absorption lines. However, a 498-nin and 504- nm pair, plus a vague smudge at 594 nm, were also seen. Strong Cape Figure 4. The 1i11kedring design in which these earrings are carved lines ordinarily indicate natural ori- is rarely seen in such fine quality natural-color jadeite jade. gin; however the suspicious fluores- cence and the lines at 498 nm and 504 nm indicated a need for further but had been treated to make it even testing. darker and thus fall into the more Figure 3, Although this 1.09-ct Consequently, the stone was desirable intense-yellow range. hncy intense yellow diamond chilled with liquid nitrogen and Clayton Welch showed the Cape series of fines tested with a spectrophotometer. in its absorption spectrum, The same absorption peaks were ob- served, but the 594-nm peak was further testing proved that it Jadeite JADE Earrings had been irradiated and an- now very definite. This confirmed nealed. that the stone had been treated by The Los Angeles laboratory recently irradiation and subsequent anneal- examined the spectacular "Imperial" ing to improve its color. jadeite jade earrings shown in figure Many treated yellow diamonds 4, Each earring consists of two trans- in the fancy color range that are lucent rings carved from a solid piece submitted for testing show a weak of jade so that they are linked to- Cape spectrum in addition to the gether chain style. The largest ring lines that prove treatment; the pres- measures approximately 18.6 mm in ence of the Cape series of absorption outside diameter, 7.2 mm wide, and lines indicates that the stone was from 2.8 to 3 mm thick. The two originally very light to light yellow rings are suspended from a third in color. However, the strength of the carved ring-shaped piece that is fit- Cape series in this particular stone ted with a yellow metal screw-back suggests that it was probably a fancy mounting, and set with five round light or fancy yellow to begin with, brilliant-cut dian~onds.

Gem Trade Lab Notes GEMS & GEMOLOGY Fall 1987 165 The earrings were proved to be natiiral-color jadeite jade on the basis of their properties: a 1.66 spot refrac- tive index, an aggregate reaction in the polariscope, and a strong 437-nn~ band with strong chromium lines in the absorption spectrum. The pieces were inert to ultraviolet radiation. An uneven color distribution was easily visible with magnification, as was the fine crystalline aggregate structure. However, both were much less noticeable with the unaided eye. The most interesting feature of these earrings is the fact that such fine-quality green jadeite was used to create a linked ring design. It has been our experience in the laboratory that usually only nephrite jade or less expensive colors of jadeite are carved in a link design, presumably because so much material is lost with this type of carving. RK Fj5ui2 5. The color in (AGin-,culiuizd pumm m.,o i,.u~cec. vv dye.

An Unusual Use chalcedony (the cryptocrystalline PEARLS for a Natural Pearl variety of quartz)with inclusions of a Black Cultured Pearls The Santa Monica laboratory was scenic nature, we seldom see crystal- The New York laboratory was re- asked to identify a fairly large but- line quartz with such picturesque cently asked to identify the single ton-shaped pearl, measuring approx- inclusions. A reader from Massa- strand of blaclz cultured pearls illus- imately 18 nlm in diameter by 13 chusetts very kindly sent such a trated in figure 5. There were 61 mm deep, that was quite ingeniously stone to the Santa Monica laboratory pearls on the strand, ranging in diam- used in a jewelry item. A watch is set for our observation and to be shared eter from approximately 11 to 14.2 into the pearl which is suspended with readers of this column. mm. At first glance, they appeared to from a detachable white metal The photo (figure 8) does not do be the expensive natural-color cul- swivel pendant set with small dia- the stone justice because the scene is tured pearls that come from the Ta- monds. This assemblage is in turn actually three-dimensional. Still, it hiti area. suspended from a white metal bow does not take much inlagination to However, the X-radiograph of pin set with numerous diamonds of visualize dust storms swirling across this same strand showed the reversal various shapes and sizes. Figures 6 a rolling desert with a n~ountainin pattern that is typically seen when a and 7 show the front and back of this the background. The jasper-like in- silver nitrate dye has been used. unique piece. clusion causing the scene cuts Because metallic silver deposited The pearl did not fluoresce to through the stone from the first row from the silver nitrate dye solution is X-rays, which indicates saltwater or- of facets above the girdle to the opaque to X-rays, it shows up as a igin. A11 X-radiograph taken through opposite side of the culet, following white ring on the X-ray. Conchiolin, the side of the pearl showed struc- the general direction of the pavilion transparent to X-rays, normally tural characteristics indicative of a facets, thus giving the three-dimen- shows up as a black ring. hollow natural pearl. However, be- sional effect when the stone is Another proof of treatment is cause of the size of the watch set into viewed from the top. the fact that natural-color blaclz the pearl we could not determine if The 43.36-ct gem is a slightly pearls fluoresce a dull orangy red to the pearl is a natural hollow blister milky, very translucent, almost red when exposed to long-wave ultra- pearl or a natural button pearl that transparent variety of quartz. The violet radiation, while dyed blaclz has been hollowed out at its base to refractive index is approxinlately pearls do not fluoresce at all, as was accommodate the watch. KH 1.545, with very little discernible the case here. These pearls may have birefringence. The specific gravity, been off-color South Seas pearls that estimated with heavy liquids, is ap- were dyed to make them more sala- Scenic QUARTZ proximately 2.65. A bull's-eye optic ble. David Hargett Although we frequently encounter figure was resolved in the polari-

Gem Trade Lab Notes GEMS & GEMOLOGY Fall 1987 Cat's-Eye SILLIMANITE (Fibrolite) The mineral sillimanite was named after Benjamin Silliman, a Yale Uni- versity mineralogist. It has also been called fibrolite, in allusion to the fibrous nature of the cat's-eye variety. Sillin~anite,an aluminum sili- cate (AliSiOs), is polymorphous (the occurrence of two or more different crystal forms having the same chem- ical formula but with different atomic structures and therefore dif- ferent properties) with kyanite and andalusite. Sillin~aniteitself is a rare collector's stone; cuttable gem-qual- ity chatoyant material is extremely rare. However, cat's-eye sillimanite has been found in the gem gravels of Sri Lanka, the Mogok region of Burma, and, more recently, in Kenya.

Figure 6.'711e front view of this Figure 7. This rear view of the unusual^ riot iiral pearl pendant pendant in figure 6 shows the gives little evidence of the watch that has been set into wntch thot has been set into the pearl. the other side of the pearl. (figure 9)was submitted to the Santa scope. The stone was inert to ultra- Monica laboratory for identification. violet radiation. CF The refractive index, birefringence, ------.. -- -. - - and optic figure proved that the stone is sapphire. Microscopic examina- Heat-Treated Yellow tion revealed natural inclusions as Figure 9. This 7.60-ct yellow SAPPHIRE well as the strain discs, very fine dot- sappl~irewas found to be heat A beautiful orangy yellow oval like "silk," and round cotton-like treated. mixed-cut stone weighing 7.60 ct inclusions that are indicative of heat treatment. Figure 8. li~clusionsin this Exposure to short-wave ultravio- Figiire 10. Blue color zones ob- 43.36-ct faceted slightly n~ill

Gem Trade Lab Notes GEMS & GEMOLOGY Fall 1987 167 A Brownish Gray TAAFFEITE The Los Angeles laboratory recently identified a 0.61-ct faceted taaffeite with the very unusual brownish gray color shown in figure 12. The stone was inert to both lone-- and short- wave ultraviolet radiation, gave re- fractive indices of 1.720 and 1.726, and showed a uniaxial optic figure in the polariscope. No absorption lines or bands were observed when the stone was examined with our stan- - dard spectroscope unit. Microscopic Fieuie 13, The rare 3,32-ct examination revealed inclusions that green cat's-eye chrome tour. have previously been seen in taaffe- rnline shown here is repor. ite: a large group of Very well devel- tedly from Tanzania, oped pseudohexagonal prismatic crystals, a whitish "fingerprint" of negative crystals, and a few bright reflective fractures. chrome tourmaline of this color seen Although taaffeite occurs in by the New York lab. Figure 11. Cat's-eye sillinlanite other colors, it is usually purple to Our client informed us that this is very rare; this stone weighs violet, with a range of saturation material was first found in the 1960s 3.44 ct. levels. This is the first brownish gray at the Landanai mine in the Umba taaffeite we have encountered in the River area of Tanzania. Apparently The Los Angeles laboratory re- lab, RK only a small part of the tourmaline cently had the opportunity to study production is of gem quality, and the 3.44-ct cabochon shown in figure most of this material is faceted; cat's- 11, a translucent to opaque very dark eye rough has been very rare. The brown, almost black, cat's-eye sil- needles that cause the chatoyancy in limanite. Spot readings revealed re- this grayish green 3.32-ct stone are fractive indices of 1.66 and 1.68, with eye-visible. The stone also showed a a birefringence of 0.02. The stone strong red reaction to the Chelsea was inert to both short- and long- color filter, and chromium lines in wave ultraviolet radiation. Our stan- the absorption spectrum. This stone dard spectroscope unit revealed a can take its place as a collector's item n~oderatelydark general absorption along with other unusual cat's-eyes up to about 490 nm, with a broad such as sillimanite, kyanite, petalite, dark band superimposed at 440 to kunzite, scapolite, and zircon, some 450 nm. The specific gravity was of which have been illustrated in estimated by the use of heavy liquids recent issues of Gems o) Gemology to be approximately 3.2. I I and the lournal of Gemmology. David Hargett It is interesting to note that Figure 12. This 0.61-ct stone is another dealer who specializes in Sri the first brownish gray taaffeite Lankan gemstones was offering sev- ever seen at the laboratory. eral cat's-eye sillin~anitesfor sale at the 1987 Tucson Gem & Mineral FIGURE CREDITS Show, an extremely unusual display The photos used in figures 1, 5, and 13 given the rarity of these stones. His were taken by David Hargett. Bob pieces ranged in weight from approx- Crowningshield is responsible lor figure A Rare Green Cat's-eye 2. Figure 3 was supplicd by Clayton imately one-half to three carats and Chrome TOURMALINE Welch. Figure 4 is 0 Harold & Erica Van included near-colorless, violet, Pelt. Robert Weldon was the photogra- brownish green, and gray hues, as Figure 13 shows a rare green cat's-eye pher lor Sigures 6, 7, and 8. Scott Briggs well as a very dark brown, almost chrome tournlaline that was re- furnished figure 9. John Koivula look the photomicrograph in figure 10. Figure 11 black stone, similar in color to the cently examined by the New York is CJ Tino Hammid. Shane McClure took stone the lab examined. RK laboratory. This is the first cat's-eye figure 12.

168 Gem Trade Lab Notes GEMS & GEMOLOGY Fall 1987 Editorial Forum

THE TERM "SYNTHETIC," adhering to this myth of consistency, Anderson con- USE AND MISUSE ceded "the inconsistency of this double standard." here referring to the use of two definitions of synthetic by The following con~mentsbear on issues addressed by many gemologists (Gem Testing, 9th ed., 1980). Lid- Hanneman (Summer 1986)and Nassau (Fall 1986)in the dicoat, in reference to his own works, states, "That I Editorial Forum section of Gems esl Gen'iology regarding could be accused of inconsistency in application of the use of the term synthetic. term synthetic I admit freely. . . .I1 (pers. comm., 1976). With regard to functional use, in the opinion of at After his early years, Webster flatly rejected the re- least eight widely recognized usage panels, convened stricted definition in both private communications to between 1962 and 1977, the term synthetic may be used the author and in his published works (Gems,3rd ed., both as a noun and an adjective. Both cases may be 1975, p. 328). Recently, Hanneman reported his similar traced ~~nbrokenlyto the ancient Greeks. observations (Gems d Gemology, Winter 1986, p. 242). As to usage in meaning only, the view held by many Nassau has difficulties of his own with consistency. gemol~giktsthat synthetic should be used only to refer In his book Gems Made by Man, he admittedly places a to man-made materials that duplicate natural gem few materials under his espoused restricted definition materials (the so-called restricted definition, as com- that clearly do not qualify. Further, he seeks relief by pared to the classic definition, which maintains that any stating: "The term 'synthetic'strontium titanate is thus man-made substance is a synthetic) is not shared by the used not in the gemological sense of being a man-made overwhelming majority of the scientific community, equivalent of a natural mineral, but in the technical nor by a number of competent gemologists, and cer- sense of having been synthesized by man." This is tainly not by the courts. I have yet to find a ruling of the indeed a strange statement. Is the discipline of gemology courts that found the restricted definition incumbent on to be excused from conforn~ingto technical sense? Not the plaintiff or the defendant. The following ruling is only does this statenlent add fuel to the opinion of those particularly relevant: who feel that gemology as a discipline is not yet One synthetic may have properties closer to the technically mature, but it also typifies the perplexity natural than others; some may duplicate the that advocates of the restricted definition create, to wit, natural; still others may have no natural coun- they cannot discuss synthetic stones in the necessary terpart. Whatever the degree of approach depth and breadth without resorting to two definitions toward duplication, the substance remains syn- of synthetic, the restricted and the classic. In short, they thetic. If the jewelry business wishes to differ- use a double standard, as acl~nowleclgedby Anderson. entiate between degrees of approach, that is its In analytical logic, when two or more definitions for prerogative. However, all classes thus estab- a single term are used in a given discipline, the usage is lished would fall under, and in specification and called Delphic and is not acceptable in argun~ent.It is a name should not compete with, the genre form of equivocation. The Delphic usage of synthetic known as synthetic. {Compliance Rulings of should be abolished. Yet some gemologists still argue for the Courts, 1975-1980, Vol. 32, Sect. 47, p. 201) continued use of this equivocation solely on the grounds that "it has long been used." Usage panels, upon first Nassau revives the myth that the restricted defini- encountering the restricted definition of synthetic, tion of synthetic has been used by all competent invariably ask how such usage came to be and from gemologists with the consistent meaning: man-made where it derives enough support to survive. As for equivalent of the natural. He invokes the names of origin, this usage evolved slowly from informal ex- Anderson, Liddicoat, Webster, and himself as examples. changes between a handful of early gemologists who In so doing, he distorts the record. After decades of agreed on a needed definition but not the term for it.

Editorial Forum GEMS & GEMOLOGY Fall 1987 169 After spasmodic mild debates and a draggy search for a values of three significant figures (i.e., values carried out suitable term, these individuals reached the baffling to the second decimal place]. Today, Archimedes is conclusion that the only solution to their problem was to probably turning over in his grave. The advent of digital take the term synthetic and redefine it for their purpose! scales and electronic calculators has made it easy to As for "enough support," it is built in. As observed generate S.G. values showing three decimal places or by Webster (pers. comm., 1974), the advocates of the even four, five, or six decimal places. Consequently, we restricted definition "all drank from the same tainted are seeing more and more comn~unicationswith S.G. font, directly or indirectly, none pausing to question the values purporting to contain four significant figures purity." To this may be added the perpetuation of e.g., S.G. =3.643). mistaken ideas by teachers through indoctrinated stu- The clear implication of such reporting is that these dents, strongly aided by the writings of those who were S.G. values have emanated from a modern "state of the similarly inculcated before them. These authors, having art" laboratory and that they should be considered of long since committed then~selvesin print to the re- higher quality than others that contain only three stricted definition, are most reluctant to admit its significant figures. With but few exceptions, this is defects. Now, when challenged, they defend this ill- nonsense. termed definition and their use and misuse of it as if it Reporting an S.G. value of, for example, 2.778 were sacrosanct. implies that the total error associated with the two If, after more than 30 years of refusing to believe required weighings is on the order of 1 part in 10,000. For that certain of its teachings regarding its ideal diamond a one-carat stone, that means the sensitivity of the brilliant might be wrong, the GIAcan in 1978 correct its balance must equal at least 1/100 of a point. In the faulty values of girdle thickness, total depth, and result- absence of experimental details that justify the fourth ing defects in its appraisal system, it should not be too significant figure, I believe it is safe to assume a priori late for responsible gemologists to accept the simpler that such results are not valid. Let me explain why. task of eliminating the double standard for synthetic Normally, S.G. determinations are made at room often found in their midst. temperature (20°Cand the results are reported to three Eugene S. Love, D.Sc. significant figures (e.g.,2.78).'Under these conditions, no errors are introduced by ignoring the effects of tempera- Boone, North Carolina ture. In addition, the S.G. taken at 20° is numerically equivalent to the density of the sample (also expressed to HOW TO USE "SYNTHETIC(S)"? three significant figures). Although most gemologists accept that density and I agree with Dr. Hanneman (Summer 1986, Winter 1986) S.G. are equivalent, the truth of the matter is that as the and Dr. Love (above]that if one 1001~sfor confusion then temperature rises, the density of a gem decreases while one will find it. Yes-there are precedents, dictionary its measured S.G. increases (due to the greater change in definitions, legal usages, and so on. However, even the the density of the water). If one is to consider the fourth authorities admit that they are not consistent, as I too significant figure, it is necessary to deal with these have not always been. Note, by the way, that Drs. effects of temperature on the measurement. If the S.G. of Hanneman and Love do not agree with each other! Such the previous example were to be measured at room sophistry could go on forever. temperature, the result might be reported as Ideally, there would be decisions made by national S.G. = 2.7831;. The superscript represents the air tenl- and international groups on such matters, so that one perature at which the weight measurements were made, could get back to the important problen~s.Yet there is and the subscript specifies the temperature of the water not even a consensus on the spelling of ge171(n1)ology.Let to which the mass of the object has been ratioed. me reiterate more clearly the closing attitude of my To make serious use of that fourth significant previous letter (Fall 1986). As long as my writings are figure, it is customary to convert all ratios to water at understood by the reader as saying what 1 intended, I am 4OC. (Density tables of water provide the factors for comfortable; if I have succeeded in communicating, that conversion from any experimental temperature.] The is all that matters to me. result in this case would then be written S.G. = 2.778f1. Kurt Nassau, Ph.D. The difference of 0.005 between this and the previously Bernardsville, NJ determined S.G. value indicates why one must report temperature data along with high-precision S.G. values.

QUO VADIS, SPECIFIC GRAVITY? A COMMENTARY - "Specificgravity is defined as the ratio of the mass (we~ght) For more than 100 years, gemological distinctions have of an oblect to the mass of an equal volume of water at 4OC been successfully made using specific gravity (S.G.) or other specific temperature.

170 Editorial Forum GEMS & GEMOLOGY Fa11 1987 lnvestigators who have been astute enough to It takes a lot of good work to determine S.G. recognize the need for temperature notations have also accurately to four significant figures. Such effort should recognized that the value of SGio is, by definition, be appreciated. Nevertheless, there is an axiom to the numerically equal to the density. Consequcntly, they effect that if a job is not worth doing at all, it is not worth simplify reporting and eliminate the need for the tem- doing well. Those who violate this axiom should be perature notations by reporting values with four signifi- judged accordingly. cant figures as density. W. W. Hanneinan, Ph.D. In spite of n~oderntechnology, the lin~itingfactor in Castro Valley, CA S.G. determinations is still the sample itself, The major premise on which all S.G. and density measurements are based is that the sample is homogeneous. While this is attainable for gaseous and liquid samples, it rarely is attainable with minerals. Experience shows that three ERRATA significant figures is the best that we can realistically We inadvertently omitted the name of the designer of expect toget. It isnot in the best interests of gemology to the unusual liunzite necklace that appeared on the begin revising the tables of S.G. ranges for gems by cover of the Summer 1987 issue, courtesy of Tiffany &> incorporating values having four "significant" figures, or Co. We are pleased to notify our curious renders, who to clutter the gemological literature with impressive- have diligently queried us, that the designer is Paloma looking "accuracy" that is essentially useless. For exam- Picasso. ple, no really useful information is imparted by report- On page 109 of the Gem Trade Lab Notes section in ing that the S.G. of corundum crystals fused together the Summer 1987 issue, the reference under the heading with a glass flux is 3.876 or that one emerald crystal, "Sappl~irine"listed incorrect page numbers. The refer- having a few inclusions, has an S.G. of 2.689 while ence should read "Fall 1985 issue of Gems & Gemology another, having more inclusions, has an S.G. of 2.701. (pp. 176-1 77):

Continued,from pnge 185 an offer to purchase the William Pinch collection. With Something new under the sun: 990 gold-a hard, high the acquisition of Mr. Pinch's exhaustive collection, the karat alloy. A. M. Tasker, K. Beilstein, and A. Reti, museum instantly gains a place among the major American Jewelry Manufacturer, Vol. 35, No. 8, museunls for scope and diversity of minerals, as well as August 1987, pp. 56-66. for excellent locality information. Patricia A. S. Gray Based on a paper that was presented at both the New York and Providence EXPOS, this article provides the NY auctions thrive under new rules. R. Shor, Jewelers' technical aspects and jewelry applications of a new alloy, Circular-Keystone, Vol. 158, No. 8, August 1987, called 990 gold, that is very nearly pure gold. pp. 448-45 1, In Hong Kong and the Far East, pure gold is preferred New York auction houses continue to do a booming in jewelry for its beauty and malleability. However, it is business despite new consumer guidelines that went too soft to meet the durability needs of Western jewelry into effect in March of this year. Essentially, these manufacturers. Using the 1% impurities tolerance for guidelines are as follows: New York auctioneers must pure gold in Hong Kong, Intergold has developed an alloy announce publicly if an item has not sold; auctioneers of 99% gold and 1% titanium that satisfies both needs. cannot bid up an item once it has passed its nlinimum The text covers the unique tempering characteris- reserve (the lowest bid that a seller will accept); sellers tics of 990 gold in extensive technical detail, as well as must prove clear title to anything that they put up for its potential application in the jewelry trade. Three auction; and auction houses must inform the seller, in figures and one table assist in explaining the properties writing, of all charges and sales commissions. According and usefulness of the alloy. to Stuart Rosenthal, spokesn~anfor the New York The alloy 990 gold is being marketed in North Consumer Affairs Department, these guidelines repre- America and is available in wrought form only at the sent "an appropriate middle ground" between auction present time. Because of the alloy's unusual age-harden- houses and consumers. ing properties, casting is not currently recommended The article goes on to expand on each of the four and care should be taken when solderine- this otherwise points, explaining the reasoning behind the guidelines. exceptional metal. In accordance with U.S. and Cana- Although, in most cases, the major auction houses have dian stamping acts, jewelry manufactured from this adhered to these practices in the past, a move toward alloy should be marked "990 Gold" or "23 ¥'karat." standardization is undoubtedly a positive step. EBM EBM

Editorial Forum GEMS & GEMOLOGY Fall 1987 171 GEM IJEWS

DIAMONDS "Filled" diamonds. In recent months, there has been considerable discussion in the trade about the distribu- tion of diamonds that have allegedly been filled to disguise cleavages and fractures, following a concept similar to that of oiling emeralds. Mr. Nubuo Horiuchi, of the Central Gem Laboratory in Japan, reported his observation in January 1987 of such a treatment, which diminishes the visibility of cleavages that reach the surface of some diamonds. According to Mr. Horiuchi's report, diamonds treated in this manner were discovered by the Central Gem Laboratory in lots imported from Israel, An unknown substance, possibly silicone, is being used both to give the cleavages a whitish appear- ance and to reduce diffuse reflections. This seems to improve the overall clarity appearance of these stones. Since August of this year, all three locations (New York, Los Angeles, and Santa Monica) of the CIA Gem Trade Laboratory have encountered a number of imper- fect diamonds that appear to have been treated by some sort of filling procedure. In September, the GIA Research Department acquired a 1.22-ct diamond (figure 1) that Figure 1. This 1.22-ct heavily included diamond was reported by the dealer to have been treated in Israel has apparently been "filled" to minimize the to fill the fractures. Prior to its arrival at CIA, the stone cracks and cleavages. Photo by Robert Weldon. had been boiled in concentrated sulfuric acid, which apparently removed some of the filling material near the surface. The result is a white, highly visible subsurface (figure 3), very different from the "feathery" appearance cruciform pattern across the table and crown of the typical of (unfilled)diamond cleavages. stone that is probably a good representation of what the The CIAis currently subjecting a number of suspect stone looked like before the filling treatment (figure 2). diamonds to a series of sophisticated tests in an effort to However, the stone also reveals a "rainbow" iridescence, identify conclusively the filling material as well as to not normally seen in diamonds, that appears to be the confirm the presence of such a material in a specific most distinctive characteristic of this treatment stone. method (again, see figure 2). The September 4, 1987, issue of the Rapaport De Beers - Botswana-and diamonds. De Beers Consoli- Diamond Report states that such a treatment method dated Mines Limited and De Beers Botswana Mining was first developed by Mr. Zvi Yehuda of Israel. He Company ("Debswana") have reached an agreement purportedly introduces a "secret" ingredient into these whereby De Beers will acquire from Debswana all of the heavily flawed stones at high pressure (50 atmospheres) rough diamond stockpiled during the period 1982-1985 and temperature (400°C)The Rapaport Report recom- (when the diamond industry was in recession). In ex- mends that buyers use 20x magnification to look for change, Debswana will receive an undisclosed cash small bubbles around the treated area in addition to payment, 5.27% of the enlarged share capital of De looking for the "rainbow" iridescence mentioned above. Beers, and the right to nominate two directors to the On one of the stones that CIA has examined, a distinc- boards of both De Beers and The Diamond Trading tive flow pattern was observed in the filled cleavages Company (Proprietary)Limited.

172 Gem News GEMS & GEMOLOGY Fall 1987 Figure 2. This white cross-like pattern on the diamond shown in figure 1 apparently was caused by removal of the filling near the surface during boiling out in an acid bath. The irides- cence also seen here is characteristic of the Figure 3. The inner surface of a filled cleavage treated portion of the cleavage system. Dark- plane in one of the diamonds examined at GIA field illumination, magnified lox;photomicro- shows the flowing rounded structures that ap- graph by John I. Koivula. pear to be typical of filling. Shadowed transmit- ted light, magnified 50~;photomicrograph by John I. Koivula. Wi~hits three major mines - Jwaneng,Letlhakane, and Orafia-Debswana has become a major diamond producer (in terms of value) over the last decade. The combined diamond production of the Debswana mines Figure 4. This 64.83-ct D-interncilly flawless and those already controlled by De Beers further diamond was auctioned nt Christie's, New York, in October 1987. Courtesy of Christie's, New strengthens the base of the Central Selling Organiza- York; photo 0 Tino Hmnid. tion. For its part, Debswana will obtain an investment in the diamond industry beyond its existing mines. The terms of this agreement are subject to approval by De Beers's current shareholders.

Large diamoiid auctioned. An unusually fine 64.83-ct pear-shaped brilliant-cut diamond was auctioned by Christie, Mason and Woods in New York on October 21, 1987. The diamond was graded D color and internally flawless, with very good polish and very good symmetry, by the GIA Gem Trade Laboratory in New York. It measures 34,10 x 22.32 x 14.79 mm. The stone does not thus far have a "name," and nothing has been released on its provenance. A photograph of this superb gem is reproduced here, in figure 4, with the kind pernlission of Mr. Franqois Curiel, of Christie's, New York.

COLORED STONES Iridescent andradite garnets. A very interesting and colorful free-form, somewhat oval, cabochon-cut gem (figure5) was given to the GIA Research Department for examination because of its unusual appearance. The stone was originally loaned to Mrs. Lillian Meyer, departmental assistant at GIA, by Mrs. Bernice Rabb, who had purchased it in Hong Kong as a black opal. The

Gem News Figure 6. Bands of iridescent color are easily seen in the stone shown in figure 5. Oblique il- lumination, magnified 20 x ; photomicrograph by John I. Koivula.

Figure 7. A different, mosaic, pattern was ob- served in the second iridescent andraditc exam- ined. Oblique illumination, magnified 10 x ; photomicrograph by John 1. Koivula. Figure 5. The stone in this ring, originally pzir- chased as a black opal, was determined to be iridescent andradite garnet from Mexico. Cour- tesy of Bernice Rabb; photo 0 Tino Han~mid. gem measures 17.17 x 13.61 x 7.80 mm. It was not removed from the mounting for weighing, and an estimated weight could not be calculated because of the free-form shape. The stone shows a most unusual play-of-color (figure 6) that at first glance gives it the appearance of an odd black opal. On more detailed examination, however, we found that the refractive index was over the limits of a standard gemological refractometer, and that the play- of-color seemed to be zoned or laminated in distinct planes and at angles suggesting a rhombic form for the original crystal. The material proved to be inert to ultraviolet radiation, and the hand-held spectroscope jewelry. A 1943 report (E. Ingerson and J.D. Barksdale, offered no additional information. On the basis of X-ray "Iridescent garnet from the Adelaide Mining District, diffraction analysis, performed by C. W Fryer, the stone Nevada," American Mineralogist, Vol. 28, pp. 303-312) was identified as andradite garnet. describes such material from Nevada. Mr. Bart Curren, At about the same time, a second, unmounted, owner of Glyptic Illusions, Topanga, California, made a polished free-form of the same iridescent andradite was field trip to the locality described by Ingerson and sent to GIA Research by the New York office of the Gem Barksdale, but with little success. Although he found a Trade Laboratory for examination. This stone had been quantity of iridescent garnets, the pieces were all very carefully cut to follow the natural rhombic dodecahedra1 small and the iridescence appeared different in its faces of the original garnet. It weighs 44.59 ct and shows structural aspects from the two stones we had exam- a mosaic iridescent pattern (figure 7) that is distinctly ined. Thus, the Nevada locality was ruled out as the different from that shown by the mounted stone in source for these much larger gems. figures 5 and 6. Subsequently, however, we met two gem and min- Iridescent garnets have been reported in the geologi- eral dealers from Mexico who had several large polished cal literature before, but never as gems mounted in free-form iridescent andradite garnets for sale. The color

174 Gem News GEMS & GEMOLOGY Fall 1987 Figure 8. These two cat's-eye quartzes (the larger stone weighs 61.25 ct) are reportedly from a new locality near Belo Horizonte, Brazil. Courtesy of Hrach Chekijian; photo by Robert Weldon.

patterns of these stones were almost identical to those The approximately 10-cm (4in.) crystal examined by the displayed by the two stones we had seen previously. Gem News editor was somewhat etched, similar to the From these dealers, we learned that the iridescent material from San Diego County, California, and con- andradites are a by-product from a calcite mine located tained complex threephase inclusions typical of peg- about 145 kn1 northeast of Hermocillo, Sonora, Mexico. matitic spodumene. To our knowledge, this is the first time that kunzite has been reported from Sri Lanlza. ~lasticikkemeralds. Mr. Nubuo Horiuchi (of the Cen- tral Gem Laboratory in Japan)also reports that a number "Rainbow moonstones" are labradorite. Dr. Henry of plastic-'treated emeralds have been observed over the Hanni, of the Mineralogical and Petrographic Institute last three years in Japan. As with oiling, the treatment of the University of Basel, Switzerland, has found only works if the fractures reach the surface of the stone. through his research into feldspar mineralogy that the With this treatment, it appears that the fractures are so-called "rainbow moonstones" coming from India are first cleaned and then impregnated with an as-yet- not true moonstone alkali feldspars, but rather arc unknown type of liquid plastic, which is then presum- labradorite feldspars. Microprobe analysis provided the ably hardened by exposure to light or ultraviolet radia- identification. tion. This treatment appears to be much more durable These labradorite feldspars get their phenomenal than oiling, but it is nonetheless still a treatment. color effects by diffraction from lamellar growth, in the According to Mr. Horiuchi, it is difficult to distinguish same way that the Finnish spectrolite-labradorites do, between the plastic treatment and oiling. and not from exsolution of albite in orthoclase - as is the Editor's note: Oiled stones have a tendency to case with true adularescent moonstones. However, be- "sweat" their oil when exposed to even slight tempera- cause they lack the ilmenite inclusions that give most ture increases (e.g.,during examination with a gemologi- labradorites a dark grayish background body color, these cal microscope). A stone that had been plastic impreg- feldspars appear white to almost colorless, and thus the nated would not show this reaction. Perhaps there may misidentification. also be a characteristic fluorescence. For extremely Phenomenal quartz from Brazil. Mr. John Bradshaw, valuable suspect gems, infrared spectrometry should be curator of the Harvard Museum's gemstone collection, definitive. The Gem News editor would greatly appreci- sent Gem News a selection of translucent to semi- ate the opportunity to examine one or more of these transparent orangy brown cat's-eye quartzes that have plasticized stones for a more detailed discussion in an been coming out of a locality near Belo Horizonte, upcoming issue of Gems a) Gemology. Minas Gerais, Brazil. The gem-quality stones examined Kunzite from Sri Lanka. Mr. Gordon Bleclz. a miner and thus far range in weight from 24.58 to 61.25 ct; they are dealer in Sri Lankan gem materials, reports that the pink the property of Mr. Hrach Chelzijian. Some of the stones variety of spodumene, lzunzite, has been found in an show weak stars with one very strong ray producing the area east of Ratnapura at Olzkampitiya. The material is chatoyancy, while others show only one strong described as medium to dark pink in color. There chatoyant ray. One of each type of stone is shown in appears to be a good quantity of gem-quality material. figure 8. We do not know how much of this material is

Gem News GEMS & GEMOLOGY Fall 1987 175 available, but the stones appear to have excellent jewelry topaz in the northeastern United States. The deposit is potential, said to be in the state of New Hampshire, but more accurate locality information was not available. The Included quartz from Mexico. Rock crystal quartz specimens from this new source are reputed to be of top containing inclusions of marcasite, with minor amounts quality. of pyrite, chalcopyrite, silver, and gold, is being produced at the Solaverna mine in Zacatecas, Mexico. The mate- Treated cat's-eye zircons. Although chatoyant zircons rial is so densely filled with marcasite and the other are not particularly common, they have been reported in inclusions that it appears almost black and, for all the literature from time to time. They are lznown to practical purposes, is opaque. The material is being cut occur in a variety of colors, such as green, brown, and into beads and sold under the trade name Solavernite. pale yellow. Mr. Gordon Bleck informs us that some of New ruby locality in Afghanistan. Mr. Gary Bowersox, these "cat's-eye" zircons have in fact been treated to president of Gem Industries, lnc., in Honolulu, Hawaii, create a false eye. To fabricate chatoyancy in zircon, Mr. reports that a new find of gem-quality ruby has been Bleck reports, "feldspar is melted onto the back of the discovered in Afghanistan, northeast of Kabul. This zircon" cabochon. However, "the backs of the cabochons mine is unrelated to the deposit near Sorobi, lznown as must be left somewhat rough in order for the treatment the Jegdalelz mine, that was reported by Mr. Bowersox in to work." Mr. Bleclz uses a simple test to detect these his article "A Status Report on Gemstones from Af- false cat's-eyes. He rubs an emery board across the back ghanistan," which appeared in the Winter 1985 issue of of the cabochon in question; if the stone has been Gems &> Gemology. treated, the cat's-eye will disappear. With a microscope, it is also possible sometimes to see small natural pits Heat-treated pink sapphires. Mr. Gordon Bleclz also has and scratches that have been filled in by the melt. informed us that many Sri Lanlzan pink sapphires are heat treated in Sri Lanlza to improve their color by driving off any blue overtones that may be present. The heating is done in air in an open fire. The temperature Acknowledgments: In addition to those individuals reached during this type of heat treatment may be as mentioned specifically in the Gem News text, the ed- high as 1 100¡C itor would like to thank Dr. Emmanuel Fritsch, Mr. C. W Fryer, Ms. Patricia Gray, Mr. Robert E, Kane, New locality for topaz. In the July 1987 issue of Mineral Dr. farnes E. Shigley, and Ms. Carol M. Stockton for News, Lanny R. Ream reported on a major new find of supplying useful information for this column.

The Tucson Gem and Mineral 742-4367. AGTA is also offering Tucson Pima County Fairgrounds, Show will be held February 11-14, special travel rates; call (800) the Desert Inn, and the Americana 1988, at the Tucson Community 972-1 163. The GLDA show will be Hotel) during the same period. Center. The featured species for the at the Holiday Inn Broadway, Febru- show is beryl. For more informa- ary 6-14; for information call (602) The Asian Institute of Gem- tion, contact the Tucson Gem and 742-5455. ological Sciences, Bangkok, Thai- Mineral Society, PO. Box 42543, The Gemological Institute of land, announces the publication of Tucson, AZ 85733. America will have various lectures its quarterly newsletter Gemologi- The American Gem Trade As- and seminars at the Holiday Inn cal Digest. Written in English, sociation (AGTA)will again be in Broadway, February 6-1 1. For infor- Gemological Digest will feature ar- TYicson, February 6-1 1, at the Dou- mation, call (800)421-7250, ext. ticles on a variety of subjects, in- bletree Hotel. Along with their 227, or write CIA, 1660 Stewart cluding gemology, jewelry, and im- usual seminars and trade shows, St., Santa Monica, CA 90404, The portant issues that affect the trade. AGTA will announce the winners American Gem Society (AGS) will The first issue, available now, con- of the Spectrum Award (a jewelry also present seminars and other ac- tains articles on the disclosure of contest aimed at the effective use tivities at the Viscount Suite Hotel, treatments and the pink sapphire of colored stones) during that time. February 3-8. Contact AGS at 5901 vs. ruby controversy. Gemological The deadline for entries for the West Third St., Los Angeles, CA Digest is free to all members of the Spectrum Award is November 4, 90036, (213)936-4367. trade. For more information, con- 1987; for information, contact the Numerous other shows will be tact the Asian Institute of Gem- AGTA headquarters at the World held at various locations around ological Sciences, 987 Silom Road, Trade Center #18 1, PO. Box TYicson (e.g., the Holiday InnIHoli- Rama Jewelry Building, 4th Floor, 581043, Dallas, TX 75258, (214) dome, the Sheraton Pueblo Inn, the Bangkok 10500, Thailand.

176 Gem News GEMS & GEMOLOGY Fall 1987 HARRY WINSTON, design books from the 17th through THE ULTIMATE JEWELER, 19th centuries. 2nd edition Incorporating modern methods of gem cutting to maximize the color By Laurence Krashes, 218 pp., illus,, BOOK and brilliance of the gemstones, and publ, by Harry Winston, Inc. (New using current technology in precious York) and the Gemological Institute metalsmithing, Alexandre Reza's of America (Santa Monica, CA), REVIEWS workshops in Paris produce sump- 1986. US$75. OO* 1 Elise B, Misiorowski, Editor 1 tuous suites of jewelry that are both current and fresh and yet echo back Dedicated to the memory of Harry to earlier centuries. Winston, this book is a lavish tribute The text describes the evolution to his skill and imagination. Vivid and additional footnotes bring more of jewelry design throughout history, and alluring, it is a spectacle of depth and clarity to the text; approx- focusing on those styles that Reza treasures and certainly a comple- imately 20 of the color pieces are new has replicated. Peppered with quotes ment to any library. to this edition. Over 130 color and 30 and anecdotes of the royalty who The book is well organized into black-and-white illustrations are in- con~missionedthese jewels and the three main sections. The first un- cluded. masters who designed and fabricated folds the fascinating life of Harry It is difficult to find any signifi- them, the book provides much inter- Winston, tracing the chronology of cant flaws in this book. Although esting information about the sym- his most notable achievements in the there are problems with the repro- biosis of art and power. Although jewelry trade. The second section duction of a few of the color illustra- emphasis is naturally placed on presents descriptions, and in most tions, this is probably due to the French jewelry design, German, cases illustrations, of 48 historically quality of the original photographs, Austrian, Italian, Russian, English, important diamonds handled by since several of the pieces date back Persian, and Indian designs are also Winston at one time or another. Al- to the 1950s and early 1960s. Other- represented. though the introduction states that wise, it appears that no detail has Unfortunately, the original "the original intention of this book been overlooked in the production. overly florid French text has been was to reproduce those entries [relat- Priced at $75.00, the book is unde- inexpertly translated and the result ing to Wihston stones] in the Gem- niably a worthwhile investment. is difficult to read and at times unin- ological Institute of America's Dia- CAROL l? ELKINS, G.G. tentionally humorous. A too-literal mond Dictionary," this second sec- Sotheby's, Beverly Hills, CA translation has given rise to stilted tion alone surpasses that intention expressions that obscure rather than by providing an updated, readable clarify the meaning of the text, along guide that rivals any reference now ALEXANDRE REZA: with a few words that are totally new available on the subject. The third to the English language. section is devoted to the genius of DREAMS OF YESTERDAY, The book was apparently com- Winston's jewelry designs. A succes- REALITIES OF TODAY. piled to document an exhibition at sion of full-color photographs and by Arlette Seta, 120 pp., illus., publ. the Iacquemart-Andre Museum, but drawings illustrate Winston's com- by Editions d'Art Monelle Hayot, further details about the exhibit are mitment "to place emphasis on the Paris, 1985; trans. by Christine not given. A foreword by Reza him- beauty of the gemstones them- tones. US$50.00* self and an introduction by Rene selves." Of these photos, fewer than Huygue, director of the Jacquemart- 10% have ever appeared in print Written as a showcase for the work of Andre Museum, give a glimpse into before. master jeweler Alexandre Reza, this the character of the otherwise enig- The author should be com- book also provides an overview of matic artist who has produced these mended for his engaging style and jewelry design throughout history. luscious jewels. A scholarly bibli- skillfulness in adding a sense of Reza's jewels demonstrate once again ography and 80 exquisite illustra- drama and excitement to the intrigu- what modern designers often forget: tions, 48 in color, are themselves ing anecdotes. The depth of informa- that there is a timelessness about sufficient reason to acquire this tion provided, especially regarding jewelry. Historically, designs in jewel- book. the provenances and subsequent his- ry are rediscovered and imitated in tories of Winston's major transac- successive centuries. Modifications ELISE B. MISIOROWSKI, G.G. tions, indicates that much thorough are made with advances in technol- Research Librarian, G.I.A. research was involved. To its benefit, ogy, but the initial beauty of a classic this second edition has been slightly jewel remains unchanged with the re-arranged and expanded from the passage of time. Reza's jewels are all original version. Having the contents replicas or adaptations of jewelry "This book is available for purchase at page closer to the beginning allows designs found in archaeological sites, the GIA Bookstore, 1660 Slewart Street, the reader to reference more quickly, Renaissance paintings, and jewelry Santa Monica, CA 90404.

Book Reviews GEMS & GEMOLOGY Fall 1987 177 CRYSTAL GROWTH simple equations. However, Brice crystals, receives a one-page descrip- PROCESSES does a good job of setting out equa- tion. tions that can guide the researcher or The final chapter is concerned By 1. C. Brice, 298 pp., illus., pbl. by engineer to make quantitative pre- with the selection and optimization Black ie/HaIste/id Press, Glasgow, dictions about the effects of chang- of methods of crystal growth, and 1986. USS61.95' ing the system variables. The under- includes a short review of the tech- John Brice is a veteran of over 25 lying principles are also well de- niques of crystal characterization. years in the field of crystal growth in scribed. This useful section, which is not the United Kingdom laboratories of The book has three main sec- usually found in a book of this kind, the giant Philips Company. A major tions. The first, comprising roughly discusses the economics of crystal contributor in the field, he has been one-third of the text, discusses the production. particularly concerned with elec- uses of single crystals and methods In summary, Crystal Growth tronic materials, including materials of growth. Thc author estimates that Processes is a book for the serious for optical devices. He has authored 900 tons of crystals are grown each practitioner of the subject, especially two previous books, Cryst(11Growth year for the jewelry industry. The one who is comfortable with apply- from the Melt ;ind Crystal Growth major part of this section discusses ing equations to compare theory from Liquids, which cover more spe- basic concepts -chemical bonding, with practice. It is probably the best cialized aspects of the subject and defects in crystals, phase diagrams, introduction to the subject of crystal have been quite popular within the the crystal surface, growth kinetics, growth for an engineer or advanced crystal-growth comn~unity.This transport processes, and an approach student, and will be of value to the third book, Crystal Growth Pro- to ;i generalized (mtithematical) de- experienced crystal grower who has cesses, is directed at scientists and scription of crystal growth. The next been used to a "seat-of-the-pants" engineers who are required to grow section, which makes up more than approach and wants to try something crystals, but it is basic enough to half the book, is devoted to each of more quantitative. Even someone serve as an introduction to the whole the major methods of crystal who does not want to get involved field of crystal growth for students growth - liquid, vapor, and solid with the equations will benefit from and others who have an interest in sources - with emphasis on elec- the discussion of fundamentals. For this subject. tronic materials. However, only two the most ptirt, however, the gemolo- Brice's main expertise is in the pages are devoted to Verneuil's gist who wants to know more about often gray area between the theory flame-fusion process, the most pop- the ways in which synthetic gem am1 the practice of crystal growth. lar for the economic growth of some crystals ;ire produced will find more The book contains a set of theoreti- gem materials such as sapphire. The on this specialized topic in Gems cal n~odelsthat attempt to specify comment that "Verneuil-grown crys- Made by Man by Kurt Nassau, or in parameters such as the crystal tals tend to be rather imperfect and this reviewer's (unfortunately more growth rate as ;I function of the suitable for uses where imperfec- expensive] Man-made Gemstones. system variables. The systems now tions do not matter (e.g., jewellery) DENNIS ELWELL, Ph.D. used to grow crystals con~n~ercially . . . illustrates the author's perspec- President, Elwell s) Assocs. are often extremely complex, and are tive. The skull-melting method, Materials Synthesis and difficult to describe by relatively which is used to make cubic zirconia Crystal Growth, Carlsbad, CA

178 Book Reviews GEMS & GEMOLOGY Fall 1987 GEMOLOGICAL ABSTRACTS

Dona M. Dirlam, Editor

REVIEW BOARD

William E. Boyajian Mahinda Gunawardene Elise B. Misiorowski GIA, Santa Monica Idar-Oberstein, Germany GIA, Santa Monica Jeffrey M. Burbank Gary S. Hill Michael P. Roach Santa Monica GIA, Santa Monica Andin International, New York Stephanie L. Dillon Steve C. Hofer Gary A. Roskin San Clemente, California Kensington, Connecticut GIA, Santa Monica Bob F. Effler Karin N. Hurwit James E. Shigley GIA, Santa Monica Gem Trade Lab, Inc., Los Angeles GIA, Santa Monica Emmanuel Fritsch Robert C. Kammerling Franceye Smith GIA, Santa Monica GIA, Santa Monica GIA, Santa Monica Joseph 0. Gill Neil Letson Carol M. Stockton Gill & Shorten Ltd., San Francisco Palm Beach, Florida GIA, Santa Monica Fred L. Gray Shane F. McClure Richter's, Georgia Gem Trade Lab., Inc., Los Angeles

COLORED STONES AND the evaluation of color are discussed. Aquamarine, the ORGANIC MATERIALS best known of the group, is described in much more Beryl: Beautiful "accidents" of nature. R. C. Kammer- detail than the others. Kamn~erlingconcludes by em- ling, Jewelers Quarterly, First Quarter, 1987, pp. phasizing that it is the inclusion of impurity elements 6-8, 10-11. that produces the different color varieties of beryl. Barton C. Curren The author has produced an informative yet easy-to-read article on three gem varieties of the mineral species Les gemmes en lumiere: Quand les grenats jouent aux beryl: aquamarine, morganite, and golden beryl (helio- opales. (Gems in light: When garnets act like dor]. For each variety, mining regions, causes of color, opals.) C. and A. da Cunha, Monde o) Mineraux, color enhancement, famous stones, history and lore, and No. 79, May-June 1987, pp. 30 and 35. The authors describe in some detail a parcel of iridescent garnets recently collected in the American Southwest. This section is designed to provide as complete a record as Iridescent lamellae exhibiting all the colors of the practical of the recent literature on gems and gemology. Articles are selected for abstracting solely at the discretion of the section rainbow are oriented in three directions on a reddish editor and her reviewers, andspace limitations may require that we black background. Microprobe analyses of a rough include only those articles that we feel will be of greatest interest to crystal and a cabochon showed that this material is a our readership. mixture of andradite, almandite, and grossular. The Inquiries for reprints of articles abstracted must be addressed to origin of the iridescence is discussed, with reference the author or publisher of the original material. made to a series of Japanese studies dealing with The reviewer of each article is identified by his or her initials at the iridescent garnets of somewhat similar composition end of each abstract. Guest reviewers are identified by their lull from Adelaide, Nevada, and Kamihogi, Japan. Two types names. Opinions expressedin an abstract belong to the abstracter of lamellae are found in both cases: one rich in iron, the and in no way reflect the position of Gems & Gemology or GIA. other rich in aluminum. The iridescence depends on the spacing and thickness of the lamellae. Three color SÂ¥1198Gemological Institute of America photographs illustrate this article, EF

Gemological Abstracts GEMS & GEMOLOGY Fall 1987 179 Jade, stone of heaven. F. Ward, National Geographic, Vol. The joy of jade. D. Kaye, Town &) Country, Vol. 41, No. 172, No. 3, September 1987, pp. 282-315. 5085, June 1987, pp. 126-129, 171. In this comprehensive article, Ward traces the history of Written for the general reader, this article covers some of jade - both nephrite and jadeite- through a first-hand the history and lore of jade and attempts to explain some account of his travels to the world's major jade-mining of the unexpectedly high prices recently paid at auction and carving localities. His narrative talzes the reader for jade items. from the Kunlun Mountains of Xinjiang Province, in the While there is some useful and interesting informa- People's Republic of China, where alluvial boulders of tion here, the article is wanting in a number of areas. white nephrite are found, to Rangoon, Burma, with its When discussing the high prices paid for various pieces, annual jade auction and gem emporium. He also de- the author does not state whether the item in question is scribes nephrite mining in such localities as British jadeite or nephrite; thus, the price paid for a necklace Columbia, South Australia, and the Arahura River of consisting of what is probably fine-quality jadeite is New Zealand, as well as jadeite recovery in Guatemala, equated with that paid for nephrite carvings of great once a source of Mayan jade. Throughout the article, the historical value. In fact, most of this discussion talzes author discusses the historical, aesthetic, etymological, place before the author ever mentions that jade is really and commercial aspects of jade, including accounts of two distinct minerals. This failure to distinguish be- jade carving in Hong Kong, dealings in smuggled jadeite tween jadeite and nephrite also carries over to the in northwestern Thailand, and the use of the Chinese photographs, where only 3 out of 15 are identified as to word for jade, yu, to describe a number of other materials type of jade. RCK suitable for carving. Of particular interest to gemologists is a section dealing with the problems of identifying the jades-and DIAMONDS their separation from a number of other materials called Cleavage surfaces of diamond. E. M. Willzs and J. Willzs, "jade" by both past and present cultures. In this respect it Industrial Diamond Review, Vol. 47, No. 518, is unfortunate that, as the author points out, archaeolo- January 1987, pp. 17-20. gists "are confusing an already muddled history by introducing a new term to encompass all carved green The smoothness and reproducibility of cleavage patterns materialÑ'cultura jade."' This section includes a dis- in gem-quality diamonds were investigated for three cussion of a portable instantaneous display and analysis groups: type I brown diamonds, which tend to cleave spectrometer (PIDAS) that can be used to identify with a rough surface; type 11 diamonds, which have artifacts thought to be jade. relatively smooth and uniform cleavages; and type I This article is very well illustrated, as we have come colorless diamonds with a high degree of lattice perfec- to expect in all reports published in National Geo- tion, which cleave more smoothly than the type I graphic. It is "must" reading for today's jeweler-gemolo- browns but less so than the type 11 diamonds. gist. RCK While stones within each group showed marked similarity in cleavage patterns, the differences between Une nouvelle varikte noble de feldspath (A new gem groups were significant. This variability is attributed to variety of feldspar). E. Gubelin, C. R. Bridges, and large-scale variations in crystal structure that arise from G. Graziani, Monde o) Minkraux, No. 79, May- the presence of impurity atoms, as revealed by X-ray June 1987, pp. 20-24. topography and cathodoluminescence studies. The Light blue to light green gemmy feldspars were recently higher concentrations of impurities in type I, especially discovered near Kioo, Kenya, 13 lzm east of Sultan brown, diamonds contribute to the rougher cleavage Hamud. They are found in pegmatite dikes that intrude surface typically observed. EF metamorphosed Precambrian sediments. The peg- matite~also contain large gem blue lzyanites, garnets, Diamond dilemma -how discounting is reshaping the quartz, black tourmalines, and vermiculite (a mica). The market. R. Shor, Jewelers' Circular-Keystone, Vol. deposit is mined with explosives and hand tools. The 158, No. 6, June 1987, pp. 134-147. feldspar is very similar in color to aquamarine; the The obsession with cost control is changing traditional luster is vitreous. The refractive indices are nm=1.531, patterns in the world diamond market. The slow cash np= 1.535 and nT= 1.539, with 2V=90°Optical mea- flow and thin margins available to sightholders have surements, together with X-ray diffraction and electron prompted them to bargain with De Beers as never before. microprobe results, indicate an oligoclase (6.2% an- At the same time, De Beers, under the new leadership of orthite) with a peristerite structure. The inclusions Nicholas Oppenheimer, appears to be listening to the observed are unique growth inhomogeneities (a picture sightholders and seems to be heeding some legitimate is provided), "fingerprints" with occasional two-phase complaints. Yet, although De Beers is watching its costs inclusions, and vermiculite crystals. Three color photo- to producers, it is also facing stiff resistance to its second graphs and eight other figures illustrate this article. EF price increase in less than a year. With an eye on world

180 Gemological Abstracts GEMS & GEMOLOGY Fall 1987 politics, the Central Selling Organization recently 13,090,407 carats, up more than 450,000 carats from moved its headquarters to Lausanne, Switzerland. How- 1985. InZaire, production increased by around 1 million ever, CSO spokesman Richard Dickson, emphasizing carats in 1986, the result, in part, of new governmental that most activity is still conducted in the London policies and regulations designed to restructure inde- office, stated that the move "has no effect on our day-to- pendent and foreign mining interests and reduce smug- day operations." gling. South African production rose only minimally. With the price and supply of diamonds controlled by The decrease in ore grades from several mines, together De Beers, the biggest cost saving available to cutters is to with the retrieval of lower-grade material from dump move production to countries where labor costs are recovery efforts, offset increases at the Premier and extremely low. Third-world countries such as China, Namaqualand mines in South Africa. Malaysia, and Thailand, as well as Hong Kong, are Namibia boosted production nearly 100,000 carats putting pressure on traditional cutting centers such as to a 1986 total of over 1 million carats. In Tanzania, Antwerp, New York, Israel, and even India. production dropped by more than 100,000 carats due to In Belgium, the devaluation of the dollar by 33%) low ore grade at the Williamson mine and a shortage of coupled with the government's crackdown on under-the- developn~entcapital. In Angola, production decreased counter payment to workers, has virtually doubled dramatically, from approximately 700,000 carats in 1985 cutting costs. Automated cutting helps some plants cut down to 200,000 carats in 1986. Civil war and the expenses, but Antwerp is no longer competitive for transition of Diainang from government owned to stones under a quarter carat. privately run are cited as the major causes for the In New York, business is strong, but price resistance decline. keeps margins small. The outloolc here is for continued Extensive exploration efforts ;ire particularly active specialized cutting of only the biggest and best because in Australia, Indonesia, China, and Sierra Leone. De of the competition from Antwerp and Israel in finished Beers is continuing worldwide exploration in Africa and sizes under 2 ct. the Americas as well. The Israeli industry has dramatically broadened its As usual, accurate production figures are not avail- share ofi the U.S. market with mass n~erchandisers, able for most diamond sources. The data used for this manufactilrers, and chains. New "grain-finding" Pier- article were compiled mainly from U.S. Bureau of Mines matic polishing machines have helped Israel remain reports and the British publication The Mining Journal. price coinpetitive in the face of increased competition It should also be noted that the article discusses total from India. rough diamond production without reference to gem vs. India, fearing competition from Asian countries industrial quality, sizes, or detailed gradeltonnage infor- that pay even lower wages, now allows importation of mation. Regardless, the article is helpful as a general and high-tech polishing equipment. Worldwide, conserva- comparative overview of 1986 diamond production tive bank lending continues to dampen speculation in worldwide. Gail L. Kirchner the market. At the same time, the Japanese buying spree appears to be losing momentum. INSTRUMENTS AND TECHNIQUES Retailers, faced with cut-throat price con~petition, are increasingly turning to Asian jewelry manufac- Confusing colourless stones. D, Kent, Journal of Gem- turers. Big firms such as Sears and Best Products have mology. Vol. 20, No. 6, 1987, pp. 344-345. both established buying offices in Israel, thus curtailing This short article is primarily a discussion of why and the business of traditional New York importers. It is how the author has assembled a collection of colorless obvious that cost cutting is changing the face of the natural gemstones and diamond simulants. The value of world diamond business. James R. Lucey the article lies in a chart Mr. Kent has included that shows infrared reflectometer readings and refractive Diamonds: Giant leap in 1986 production. J. Roux, indices for each of the 39 faceted gem materials in his Jewellery News Asia, No. 36, August 1987, pp. collection, along with carat weight and specific gravity. 45-50. It is interesting to see the correspondence between the In 1986, world diamond production soared to a record infrared reflectometer readings and R.I. EBM height of more than 88 million carats. This leap was primarily the result of Australia's 1986 diamond produc- JEWELRY ARTS tion figures, which swelled to over 29 million carats from the 1985 figure of approximately 7 million carats. B is for beautiful. C. Seebohm, Connoisseur, Vol. 217, This surge elevated Australia to the world's largest No. 902, March 1987, pp. 59-65. dian~ondproducer. Production in other countries Daughter of jewelry giant Constantine Bulgari, Marina changed little, except for Botswana and Zaire, both of Bulgari was raised with an understanding of, and appre- which showed substantial increases. ciation for, fine jewelry. From the age of 12, Marina was In Botswana, diamond production increased to involved in her family's business; steadily, she developed

Gemological Abstracts GEMS & GEMOLOGY Fall 1987 181 her talent as a designer. In the 1970s, when the third Ms. Eluere begins by discussing classic historical generation of Bulgaris inherited control of the company, references to torques in literature and sculpture. She Marina found that "there were too many of us with too then examines torques classified in groups according to many differing philosophies." Needing the freedom to their different terminals and clasps. These categories express herself, Marina broke away from the company; were selected because they reflect advances in technol- in doing so, she agreed to the stipulation that she not use ogy* the Bulgari name. In 1979, Marina opened her first It is hard to characterize as "barbarian" a culture jewelry showroom in Geneva as simply Marina B. that devised such sophisticated fasteners and intricate Marina Bulgari's opulent and extraordinary designs and graceful designs. Strong and bold, but accented with are intricately fabricated, with interchangeable parts, details, these pieces are worthy of close examination by swivels, hidden springs, and invisible clasps, so that the jewelry designers today. jewels are as comfortable to wear as a piece of clothing. Tribute must be paid to the exhaustive research that She makes good use of a variety of gems and precious went into the writing of this paper. Although it seems a metals, mixing them with a "disdain for intrinsic value." bit clogged with dates and locations (a map would have Topaz, citrine, amethyst, and tourmaline are accented been helpful), the information is worth digging for. Over with diamonds, black enamel, or black mother-of-pearl, 25 photographs, many in color, embellish the text, and and set in gold or platinum. Her designs also make use of 48 references are cited. EBM cabochon stones because, as she claims, they "create volume." Marina's often custom-designed, one-of- a-kind jewels command extravagant prices that main- JEWELRY RETAILING tain her exclusivity. The author has performed a service by providing Perlstein victims unpaid; judge rewrites restitution. W. this glimpse into the private Bulgari world, and focusing Keane, National Jeweler, August 16, 1987, p. 12, deserved attention on a dedicated and innovative artist. Keane updates the case involving Ron Perlstein, Phila- The text is accompanied by eight rich photographs of delphia's "discount diamond king," who was ordered by Marina B. jewels. EBM the court to pay restitution to 613 of his customers. As of July 1987, only 33 customers had received any of the How to copyright your designs. I? L. Berger, American payment ordered by the court in 1986. In an effort to Jewelry Manufacturer, Vol. 35, No. 6, June 1987, speed up the repayment, a municipal court judge in pp. 24, 26, 28. Philadelphia imposed a new restitution order on July 13, Jewelry manufacturers may effectively protect their 1987. However, Perlstein is saving $200,000 as the result designs by registering them with the U.S. copyright of the court's restitution rewrite. Some victims are office. This article outlines the procedures a iewelrv furious with the court; others are willing to take the manufacturer or designer must follow to register origi- lesser amount. Customers have the option of taking the nal designs with that office. diamonds as advertised, a cash amount, or store credit. Applying for a copyright is actually very easy. GAR Unlike patents, a copyright can be obtained without the aid of a lawyer. It requires a simple three-step process: (1) The Tiffany standard. C. Hemphill, Town e) Country, fill out Form VA, including drawings or photographs of Vol. 141, No. 5080, January 1987, pp. 158-164. the design; (2)attach a check to cover the $10.00 fee; and To commemorate the 150th anniversary of Tiffany & (3)mail the information to the Register of Copyrights, Co., the author presents a fascinating historical sketch Library of Congress, Washington, DC 20559. A manu- that focuses on the people who contributed most to facturer may register several designs at one time pro- Tiffany's superior international reputation. Through vided the proper guidelines are followed. The author also brief vignettes, we follow the growth of the company gives several pertinent examples of how designers and from novelty shop and dry-goods store to an exclusive manufacturers can protect themselves with a copyright. jewelry establishment that has catered to the elite since Juli L. Cook the turn of the century. Although Charles L. Tiffany, the founder, had an Celtic gold torcs. C. Elukre, Gold Bulletin, Vol. 20, No. understanding of the American public's taste during the 112, 1987, pp. 22-37. 19th century (a bit vulgar and sensational), he nonethe- This article is a detailed study of gold torques, or less had a "seriousness of purpose and a ruthless stan- neckrings, worn by the barbarian Celtic tribes in Europe dard of quality." Among the designers who made Tiffany and the British Isles from roughly the 5th to 1st & Co. great: silversmith Edward C. Moore, who re- centuries B.C. Using modern technology, the author flected the classical and Rococo revivals of the 1850s and analyzed the gold alloys used, and postulates on the tools 1860s; Louis Comfort Tiffany, known for his magical that would have been employed to fabricate these opalescent glass and unusual Art Nouveau jewelry in deceptively simple ornaments. the early 1900s; Van Day Truex, whose bold colors and

182 Gemological Abstracts GEMS & GEMOLOGY Fall 1987 provocative designs during the 1950s brought life back ducers covered are: Verneuil, Hautefeuille and Perrey, to the "ghastly good taste" that typified Tiffany's during Chatham, Gilson, Zerfass, Lennix, lnan~ori,Seilzo, the war years; Jean Schlumberger, the Parisian designer Lechleitner, Linde, Regency, and Bison. A final paragraph who joined Tiffany's in 1956 and continues to produce is dedicated to a short description of beryl substitutes. highly stylized jewelry in a colorful mixture of mythical Hand-rendered sketches depict the most typical and natural subjects that is his translation of Renais- inclusions in the various synthesized emeralds. Al- sance mannerism, Elsa Peretti, a Roman aristocrat though the examples are realistic enough to impart a whose stylized organic designs in silver became wildly feeling that one could recognize the inclusions in real popular in the 1970s; and Paloma Picasso, who in the stones, one cannot help but wonder why photomicro- 1980s is proving herself with strong, simple jewels graphs were not used, incorporating large colored gems. Although not a jewel- For the gemologist fluent in Spanish who has long ry designer, Gene Moore, the celebrated window dresser wondered about the translations of some of the more for Tiffany's, is also given deserved attention. The technical gemological terms, this is an excellent oppor- several presidents of Tiffany's are mentioned as well, but tunity to exercise and understand the terminology in they must take a place in the background to the creative another language. The article is well researched, the individuals who set the Tiffany standard. Photographs of information cleverly compounded, and the bibliography several of the designers are included, together with an gives the reader recourse to further information. example of each one's work. EBM Robert Weldon The first plastic. R. Friedel, Invention and Technology, SYNTHETICS AND SIMULANTS Summer 1987, pp. 18-23. Czochralski growth of alexandrite crystals and investi- The first plastic emerged from man's desire to produce a gation of their defects. X. Guo, M. Chen, N. Li, Q. material that could replace ivory in billiard balls. John Qin, M. Huang, J. Fei, S. Wen, Z. Li, and Y. Qin, Wesley Hyatt, a New York printer, invented the first Journal of Crystal Growth, Vol. 83, 1987, pp. plastic, a celluloi'd, in 1869. Experiments in the 1880s 31.1-318. and 1890s resulted in a celluloid material that could be Optical-$quality crystals of synthetic alexandrite have easily shaped and dyed to look like ivory, tortoise shell, been grown by the Czochralslzi method. These crystals and mother-of-pearl. Although this celluloid failed as a are up to YO mm in length (along the c-axis)and 18 mm billiard ball, its most important attribute was its ability in diameter. Oxide starting materials mixed in stoi- to imitate items of rarity andvalueat a much lower cost. chiometric proportions are used to produce (by solid- The celluloid material appealed to the tastes of the state reaction at 1300° for 12 hours) a sintered block of turn-of-the-centurv middle classes. The substance lent polycrystalline alexandrite. This block is then melted in itself to a great range and variety of ornamental uses. As an iridium crucible and the crystal is grown by the a result, it was mass-produced into letter openers, Czochralslzi method at 1870°C Crystals have been jewelry boxes, combs, and sewing kits. In addition to its grown oriented along the [100], [010], and [001] direc- decorative uses, celluloid became a very important tions. The crystals exhibit a distinct anisotropy of component of early photographic film. growth rates along these three directions such that The commercial importance of celluloid continued [100]>[010]>[001]. Various structural features ob- through the 1930s, although rival products had begun to served with an optical n~icroscope in these crystals emerge. The flammability of celluloid was incentive to include bubbles, inclusions, dislocations, and grain produce substitutes in the growing film industry and boundaries. These features were examined in greater elsewhere. At present, little celluloid is produced in the detail using both transmission and high-resolution elec- United States. There are very few applications for the tron microscopy, and were found to be related to defects substance, and its use is confined to the manufacture of generated during crystal growth. IES certain fuses and obscure decorative ornaments. Juli L. Cook Esmeraldas sintkticas, sustitutos e imitaciones de es- mer;ilda (Synthetic, substitute, and imitation em- New investigations of synthetic amethysts produced in eralds). M. A. Pellicer, F. Gascon, and M. Baquero, Japan. Th. Lind and K. Schmetzer, Journal of Cuadernos de Gemologia, No. 4-5, Jan- Gemmology, Vol. 20, No. 5, 1987, pp. 274-277. uary-December 1986, pp. 147-1 57. This article addresses further separations of natural This article, written in Spanish, describes the history versus synthetic amethysts. The authors focus specifi- and major developn~entsof synthetic emerald produc- cally on the diagnostic properties of the synthetic tion. The authors begin with the first efforts of Mr. amethyst produced in Japan, which differs from that Ebelnian of France, in 1848, and continue through the produced in Russia (used in earlier studies). present production and development; basically, the The synthetic amethyst produced in Japan is char- article is a succinctly presented chronology. The pro- acterized by fluid inclusions and two-phase inclusions,

Gemological Abstracts GEMS & GEMOLOGY Fall 1987 183 sharp lamellar structures connected with distinct color clusions and flat included crystals are also common in zoning (observed parallel to one rl~ombohedralface of this group. These three samples are believed to be grown the synthetic amethyst), and twinning confined to by the Czochralslzi method. Thirty-two good-quality distinct areas of the synthetic crystal, all of which were color photographs illustrate this article. EF observed with an immersion microscope. Furthern~ore, these synthetics exhibit the additional (albeit some- TREATMENTS times lower intensity) absorption band in the infrared area of the spectrum that previously has been observed Colour and irradiation-induced defects in topaz treated to be characteristic of synthetic amethyst. with high-energy electrons. K. Schmetzer, Journal With the observations made in this study, the of Gemmology, Vol. 20, No. 6, 1987, pp. 362-368. distinction of natural and synthetic amethyst continues This second article by Dr. Schmetzer on irradiated blue to depend primarily on n~icroscopicstudy of the speci- topaz (the first was abstracted in the Summer 1987 issue men under immersion, most importantly for the obser- of Gems o) Gemolosyl purports to be "a detailed vation of twinning features. Therefore, the authors description of the coloration and different types of recommend detailed knowledge of the various proper- electron-induced defects in irradiated topaz." The study ties of polysynthetic twinning in natural amethyst involved spectroscopic exan~inationof parcels of based on the Brazil law. Deborah Jean Martin Nigerian topaz that had been treated in a linear accelera- tor and then heated, topaz (of unspecified locality) that Synthesis of rose-quartz crystal. M. Hosaka, T Miyata, had been treated by gamma rays and high-energy elec- Y, Shimizu, and 0. Okuyama, Journal of Crystal trons followed by heating, and other samples of topaz Growth, Vol. 78, 1986, pp. 561-562. treated by neutron irradiation. Samples of naturally While the massive form of rose quartz is relatively colored blue topaz from Brazil, Nigeria, and Zimbabwe comnlon, crystals of rose quartz are rare in nature. This were also studied for comparison. Coloration, color article reports on the synthesis of a rose-quartz crystal zoning, and pleochroisn~are described for the treated by hydrothermal growth. Using a seed crystal and pieces samoles in some detail. A review of the color centers as of massive rose quartz as a nutrient material, a crystal of determined from polarized spectra essentially summa- colorless quartz was grown at 330° from a titanium- rizes the more complete description in Schmetzer's containing alkali solution. The growth period was 10 to Natiirwissenschciften article. 14 days. The resulting colorless crystal was then heated Photomicrographs accompany a discussion of at 1200° in a platinum crucible containing calcium cracks and needle-like defects associated with the var- carbonate powder to which 0.5 wt.% iron was added. ious types of irradiation damage. Dr. Schmetzer con- After heating, the colorless crystal turned pink and was cludes with exvianations of how the defects observed in semitransparent. These results suggest that the ti- electron-irradiated blue topaz arise from charge build- tanium was incorporated in the quartz crystal structure up and differential thermal conductivity and expansion during hyclrothermal growth, while the iron was incor- during the treatment process. CMS porated during subsequent heat treatment. The results also support the Ti'^-Fez+ charge-transfer mechanism Irradiated gemstones: Could the ice be hot? K. Nassau, thought to give rise to the pink color of natural rose Lapidary Journal,Vol. 41, No. 5, August 1987, pp. quartz. EF/IES 41-46. Although infrequently, radioactive gemstones have been Synthetic alexandrite from USSR. C, Trossarelli, La reported in the jewelry trade. This raises the question of Gemmologia, Vol. 11, No. 4, 1986, pp. 6-22. whether or not these stones represent a problen~,and, if The author describes synthetic alexandrite reportedly so, to what extent the industry should be concerned. produced in the USSR. He examined 15 cut pieces The purpose of irradiating gem materials is to (0.04-0.70 ct)and three semi-rough samples (94-1 17 ct). intensify, produce, or change color. Many gemstones All of the sample stones exhibit pleochroisn~,fluores- that reach the jewelry industry have been treated in this cence, and absorption spectra typical of alexandrite. The manner, and such stones do not present a hazard if the author points out the importance of crystallographic irradiation process has been performed properly. A orientation in obtaining a good color-change effect reputable operator will check for significant radioac- (unfortunately, without further explanation). When ex- tivity and will hold each parcel of irradiated gem amined with the microscope, cut stones exhibit flux material until the level is acceptable. "fingerprints," with occasional two-phase inclusions, as Nassau argues that gemologists should consider well as dark color concentrations that appear in straight making a radiation check part of any gemological lines. The cut samples are, therefore, believed to be examination. Simple instruments are available to con- grown by the flux method. The semi-rough samples, duct such tests; the best known is the Geiger counter. To however, display curved striae and curved streams of perform an accurate test, one should determine back- bubbles. "Tailed" negative crystals, parallel tubular in- ground radiation in the absence of the gem specimen.

184 Gemological Abstracts GEMS & GEMOLOGY Fall 1987 Next, a reading should be taken of the stone. Any men. However, as this depends on the mineral itself, significant elevation above the background reading, in perhaps one should infer from the omission that experi- the author's opinion, should be considered undesirable, ence and experimentation are the best ways to learn despite the fact that there are no official guidelines for these subtleties. pern~issiblelevels of radioactivity in gemstones. Inclu- For a beginner wishing to photograph minerals, this ded are two helpful tables: One lists the rays and article, as well as the previous ones by Mr. Scovil, are particles used to irradiate gemstones, and the other invaluable. Robert Weldon describes the color changes that comn~onlyresult. The glitter of Southeast Asia. R. Brus, Diamond World full L. Cook Review No. 42, 1987, pp. 64-66, 68, 70. Pa. jewelers rally to fight bill on treatment disclosure. J, Brus presents an interesting article filled with the Everhart, National Jeweler, August 16, 1987, pp. history and tradition of the treasures of Southeast Asia. 14, 58. As far back as 1783, the Dutch were exporting Pennsylvania lawmakers are considering a piece of $200,000-$300,000 worth of diamonds annually from legislation, Senate Bill 497, that would require jewelers Borneo's diamond mines. Not surprisingly, Bornean to disclose gem treatments at the point of sale. The diamonds were used for centuries in state regalia and Pennsylvania Jewelers Association (PJA)opposes the bill. private jewelry. Much of the royal regalia has been put on They are not necessarily against disclosure, but they are public display in museums such as the National Mu- concerned about the cost of compliance, the paperwork, seum of Jakarta and the Grand Palace in Bangkok. and the provision that would allow the consumer to file Ornate costumes decorated with silver, gold, and charges against the jeweler within one year after the precious gems were traditionally associated with power discovery that the "gem was treated and disclosure not in Southeast Asia. The royalty also wore elaborate made." The PJA contends that jewelers already provide jeweled crowns, many of which were exceedingly heavy treatment information and that, in the event disclosure and uncomfortable. For example, the diamond-and-ruby is not made, current legislation covering misrepresenta- coronation crowif in Thailand weighs over 16 Ibs. tion and'ffaud also applies to jewelers. This interesting The regalia of this region continues to be treated article gives some detail on how legislation evolves at with great respect and tradition. Some objects are, to the state level and the role a jewelry association can this day, offered fresh flowers, incense, and rice at least perform i~ithe legislative process. CAR weekly, all of which adds to the glitter of Southeast Asia. Barton C. Curren MISCELLANEOUS The National Museum of Natural Sciences, Ottawa, Mineral photography, film and lights. J. A. Scovil, Rocks Canada. J. D. Grice, Rocks and Minerals, Vol. 62, and Minerals, Vol. 62, No. 4, 1987, pp. 258-262. No. 5, 1987, pp. 321427. Mr. Scovil has added a new article to his series on This installment of the magazine's "Collections and mineral photography. In this installn~ent,he primarily Displays" series features Canada's National Museum of discusses film choices and lighting techniques as they Natural Sciences [NMNS). The author, division chief affect mineral photography. and curator in the mineral sciences division, begins with As in the previous articles, Scovil again incorporates a brief history of the museum, starting from its incep- his own "do-it-yourself" suggestions, such as the home- tion in 1842. Highlights of the mineral collection are made photo-stand and the fiber-optic light source. These also included, illustrated with 14 black-and-white pho- ideas are clever as well as helpful, since the photography tographs. The collection emphasizes North American of minerals is not an exact science and depends on the minerals, with approximately 50% of the more than nuances of each individual piece. In addition, resorting 20,000 specimens being of Canadian provenance, and to "do-it-yourself" techniques and equipment is often an 25% coming from the United States. economical way to achieve beautiful results. There are 1,500 gemstones in the collection, again, Mr. Scovil also presents useful data, such as the the emphasis is Canadian, as Dr. Grice cites the neces- color temperature of lights and the effects of lights on sity of purchasing stones at a "reasonable" price. The film. It would have been helpful to see a reference chart, result is a diverse assemblage of rarely cut stones as and perhaps a few photographic samples of the ways in opposed to the more commonly known diamond, sap- which light affects film. As it is, the article covers this phire, ruby and emerald. topic quite well -with one notable exception: the prob- The article concludes on a hopeful note: Although lem of how to photograph color-change minerals such as very little of the collection is presently on display (one alexandrite and change-of-color sapphire and garnet. has the impression that this is due to lack of space), a Noting the title of this article, one might have permanent mineral gallery is planned for the future. Of expected to see an expanded list of suggestions on the particular interest is the fact that the NMNS has signed positioning of lights with regard to the mineral speci- Continued on page 171

Gemological Abstracts GEMS & GEMOLOGY Fall 1987 185 GEMS & GEMOLOGY is an inter- f national publication of original con- tributions (not previously published in English) concerning the study of gemstones and research in gemology and related fields. Topics covered include [but are not limited to) col- ored stones, diamonds, gem instru- ments, gem localities, gem substi- tutes (synthetics),gemstones for the Previous Studies, Methods, Results, should be considered whenever the collector, jewelry arts, and retail Discussion, Conclusion. Other heads bulk of information to be conveyed management. Manuscripts may be and subheads should be used as the in a section threatens to overwhelm submitted as: subject warrants. For general style, the text. Original Contributions-full-length see A Manual of Style (The Univer- Figures. Please have line figures articles describing previously un- sity of Chicago Press, Chicago). (graphs, charts, etc.) professionally published studies and laboratory or References. References should be drawn and photographed. High-con- field research. Such articles should used for any information that is trast, glossy, black-and-white prints be no longer than 6,000 words (24 taken directly from another publi- are preferred. double-spaced, typewritten pages] cation, to document ideas and facts Submit black-and-white photo- plus tables and illustrations, attributed to-or facts discovered graphs and photomicrographs in the Gemology in Review-comprehcn- by-another writer, and to refer the final desired size if possible. sive reviews of topics in the field. A reader to other sources for addi- Color photographs-35 mm slides maximum of 8,000 words (32 dou- tional information on a particular or 4 x 5 transparencies-are ble-spaced, typewritten pages] is subject. Please cite references in the encouraged. text by the last name of the author(s) recommended. All figure legends should be typed and the year of publication-plus Notes & New Techniques-brief double spaced on a separate page. the specific page referred to, if ap- preliminary communications of re- Where a magnification is appropri- propriate-in parentheses (e.g., Lid- cent discoveries or developments in ate and is not inserted on the photo, dicoat and Copeland, 1967, p. 10). gemology and related fields (e.g., new please include it in the legend. The references listed at the end of instruments and instrumentation the paper should be typed double techniques, gem minerals for the spaced in alphabetical order by the MANUSCRIPT SUBMISSION collector, and lapidary techniques or last name of the senior author. Please Please send three copies of each new uses for old techniques). 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Scientific American, Vol. Editor, one of the Associate Editors, mately 150 words for a feature arti- 234, pp. 84-95. and at least two reviewers. The au- cle, 75 words for a note)should state Liddicoat R.T. Jr., Copeland L.L. thors will remain anonymous to the the purpose of the article, what was (1967)The Jewelers' Manual, 2nd reviewers. Decisions of the Editor done, and the main conclusions. ed. Gemological Institute of are final. All material accepted for Text. Papers should follow a clear America, Santa Monica, CA. publication is subject to copyedit- outline with appropriate heads. For Tables. Tables can be very useful in ing; authors will receive galley proofs example, for a research paper, the presenting a large amount of detail for review and are held fully respon- headings might be: Introduction, in a relatively small space, and sible for the content of their articles.

186 Suggestions for Authors GEMS & GEMOLOGY Fall 1987