Winter 2004 Gems Gemology - GIA 2004 VOLUME 40, ... Natural diamond containing Ni • Chalcedony...

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Transcript of Winter 2004 Gems Gemology - GIA 2004 VOLUME 40, ... Natural diamond containing Ni • Chalcedony...

  • pg. 307

    VOLUME 40, NO. 4Winter 2004

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    REGULAR FEATURES _____________________Lab Notes

    Faceted apophyllite with crop circles Luminescent hopper diamond Magnetic natural pink diamond Diamond with many microscopic carbonateinclusions Unusual near-colorless synthetic diamond Orangy brown iolite fromMadagascar Flashing labradorite Natural saltwater mussel pearls Treated-colorgolden South Sea cultured pearls Quartz in three colors

    Gem News International

    Natural diamond containing Ni Chalcedony from Iran Clinohumite fromTajikistan Corundum-fuchsite-kyanite rock from India Cristobalite and opal mix-ture from Madagascar Jeremejevite from Madagascar Kyanite from Tanzania Sapphires from Afghanistan and Pakistan Sapphires from Baffin Island, Canada Unusual star and cats-eye sapphire Cats-eye topaz from Ukraine Triplitefrom Pakistan Gem localities in Zambia and Malawi Barite spears in fluorite Inclusions in Arizona peridot Double-eye chatoyant quartz Graphite inclusionsin quartz from Brazil Quartz with molybdenite Rutile moth in quartz Synthetic corundum with unusual color zoning Imitation clam pearl

    Book Reviews

    Gemological Abstracts

    2004 Index

    The Last Page: Diamond Animation on Our Fall Cover

    EDITORIAL _____________First GIA Gemological Research ConferenceAlice S. Keller

    LETTERS ____________

    FEATURE ARTICLES _____________The Creation of a Magnificent Suite of Peridot Jewelry:From the Himalayas to Fifth AvenueRobert E. Kane

    Chronicles the making of a peridot jewelry suite, from the rough mined inPakistan to the design and manufacture of the ensemble by Van Cleef & Arpels.

    An Updated Chart on the Characteristics of HPHT-Grown Synthetic DiamondsJames E. Shigley, Christopher M. Breeding, and Andy Hsi-Tien Shen

    Summarizes the features of synthetic diamonds currently in the gem marketthat are grown at high pressure and high temperature (HPHT) conditions.

    NOTES AND NEW TECHNIQUES ______A New Method for Detecting Be DiffusionTreated Sapphires:Laser-Induced Breakdown Spectroscopy (LIBS)Michael S. Krzemnicki, Henry A. Hnni, and Roy A. Walters

    Presents a new analytical technique for detecting the presence of berylliumdiffusion in corundum.

    pg. 338

    pg. 331

    pg. 297

  • s readers of this journal know, modern gemology isexpanding in many exciting directions. Although tradi-tionally rooted in mineralogy and geology, gemology

    now extends into fields such as physics, chemistry, and mate-rials science. This evolution has come in response to increas-ingly sophisticated synthetic gem materials and treatments, aswell as the availability of natural gems from an ever greaternumber of sources. Much ofcontemporary research isfocused on the nondestructivecharacterization of gem materi-als to document their gemologi-cal properties and determinemeans of identificationof thegem material itself, whether it isnatural or synthetic, and thecause (natural or treated) of itscolor and other features. At thesame time, advanced geologicfieldwork at known gem locali-ties, and the documentation ofnew deposits, continues to yieldimportant insights into the origins of gems.

    To explore the latest breakthroughs in gemology and related sciences, GIA will host its first-ever Gemological ResearchConference August 2627, 2006, in San Diego, California, at theManchester Grand Hyatt Hotel. This event, held in conjunctionwith the 4th International Gemological Symposium (August2729), is being co-chaired by two prominent G&G authors andeditors, Dr. James Shigley and Brendan Laurs. The Conferencewill not only provide an international forum for gemologists toshare the results of their latest studies, but it will also give scien-tists and specialists from other disciplines an opportunity to contribute to modern gemological research. GIA hopes to holdsubsequent research conferences on a regular basis.

    The following six general themes (scheduled in two parallelsessions) will be addressed at the 2006 conference:

    Gem Characterization Techniques Diamond and Corundum Treatments Laboratory Growth of Gem Materials Geology of Gem Deposits New Gem Occurrences General Gemology (including Pearls)

    Each session will feature invited lectures and submitted pre-sentations by prominent gemologists and other researchersfrom around the world, plus opportunities for interactive

    discussions with audience members. In addition, a poster session will take place on August 27, for which participantscan submit innovative research on any topic of gemologicalinterest. Poster session presenters will be encouraged toshow samples, with gemological microscopes available foruse. Poster presenters may also leave their exhibits up forviewing during the International Gemological Symposium,

    which will follow immediately.

    Potential presenters are asked tosubmit an abstract in electronicformat by March 1, 2006.Abstracts for oral presentationsshould be submitted to the organizing committee at gemconference@gia.edu.Abstracts for poster presenta-tions, and requests for informa-tion on poster guidelines, shouldbe submitted to Dona Dirlam atddirlam@gia.edu. Abstracts forboth oral and poster presenta-

    tions given at the research conference will be published byGems & Gemology in a special Proceedings volume.

    The science of gemology is the key to preserving the integrityof the gem industry. As new treatments and synthetics areintroduced, and new gem materials appear in the market-place, we must develop the intellectual resources to addressthem. The GIA Gemological Research Conference will helpshape the future of our science.

    I urge you to join us in San Diego in 2006 for both theGemological Research Conference and the InternationalGemological Symposium. For more information on participat-ing as a presenter or attendee at the Conference, visit G&Gonline at www.gia.edu/gemsandgemology and click on theGemological Research Conference link, or send an e-mail togemconference@gia.edu. Regular updates on this Conferenceand the 4th International Gemological Symposium willappear on GIAs Web site at www.gia.edu.

    You, too, can help shape the future of gemology.

    Alice S. KellerEditor-in-Chief

    A

    First GIA Gemological Research ConferenceWill Kick Off 2006 International Gemological Symposium

    EDITORIAL GEMS & GEMOLOGY WINTER 2004 283

  • LETTERS GEMS & GEMOLOGY WINTER 2004 285

    Photoluminescence Peak in Synthetic Diamonds Due to Ruby Inclusions?In the Summer 2004 G&G (pp. 128145), Shigley et al.reported on a comprehensive study of colored syntheticdiamonds distributed by Chatham Created Gems. In thisarticle, the authors ascribe a photoluminescence featureat 693 nm seen in the pink synthetic diamond samples toa nickel-related defect. I assume this is because, in theirreferences, A.M. Zaitsev (Optical Properties of Diamond:A Data Handbook, Springer Verlag, Berlin, 2001) quoteda center at 693.7 nm that was ascribed to nickel by V.A. Nadolinny.

    I would like to suggest that there is ample evidencethat what the authors have probably seen is, in fact, theCr3+ ruby doublet, such as that seen in near-colorless syn-thetic diamond and documented on my Web site atwww.gis.net/~adamas/raman.html.

    The authors state that the synthetic pinks they exam-ined were type IIa (Ibs with low nitrogen) and containedmetallic inclusions. This is consistent with the charac-teristics of near-colorless synthetic diamonds, which usealuminum as a nitrogen getter. The getter seems toresult in precipitation of the flux into the crystal as wellas eliminating the nitrogen, and where you have alu-minum, you typically create oxides, trapping oxygen.The use of low-purity iron and nickel for a catalyst is asource of trace chromium, all the necessary ingredientsfor the formation of Al2O3 + Cr

    3+, i.e., ruby.At room temperature, the ruby doublet exists at

    692.9 nm (1.789 eV) and 694.3 nm (1.785 eV), with theprimary luminescence peak shifting with decreasingtemperature to 693.4 nm (1.788 eV; see M. J. Weber,Handbook of Laser Wavelengths, CRC Press, BocaRaton, Florida, 1999).

    K. Iakoubovskii and G. J. Adriaenssenss high-resolu-tion photoluminescence data on a Co-grown syntheticdiamond (Comment on Evidence for a Fe-related defectcentre in diamond, Journal of Physics: CondensedMatter, Vol. 14, No. 21, 2002, pp. 54595460) andAdamas Gemological Laboratorys lower-resolution (0.35nm quantization/pixel) SAS2000 photoluminescencedata on multiple samples and multiple-sourced Ni-Fecatalyst near-colorless synthetic diamonds, clearly showthe presence of this ruby doublet.

    Possibly because of the very, very strong laser-induced broad-band fluorescence in the two samples of

    Chatham pink synthetic diamonds I have, I have notbeen able to personally resolve the 693 nm featureusing either 488, 514, or 532 nm excitations. This mayalso be due to the requisite low integration times,although the authors noted that the feature was rare,occurring in less than one-third of the samples tested,somewhat consistent with our statistics (see web pageabove) on the feature in near-colorless synthetic dia-mond. It would be interesting to know whether, in theauthors samples tested, there was a correlationbetween fluorescence strength and observability of the693 nm feature.

    Martin D. HaskeBrookline, Massachusetts

    Reply

    We appreciate the opportunity to respond to Mr. Haskescomments, but we disagree with his suggestions. Uponcloser inspection (see figure 1), the luminescence feature

    LETTERSLETTERS

    Figure 1. These photoluminescence spectra (takenunder identical conditions at 77 K) show the classicruby doublet in corundum at 692.0 and 69