Diamond - Color |
Posted/ Published | Author | Title | Source | Region | Keywords |
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DS1910-0470 1915 | Mennell, F.P. | Note on the Colours of Some Alluvial Diamonds | Mineralogical Magazine., Vol. 17, No. 81, PP. 202-204. | Zimbabwe | Coloured Diamonds, Crystallography |
DS1950-0260 1956 | Brendler, W. | Gruene Diamanten aus Suedafrika | Aufschluss, Vol. 7, PP. 2-4. | Southwest Africa, Namibia, South Africa | Diamond, Morphology, Colour |
DS1960-0696 1966 | Lenzen, G. | Die Qualitatsmerkmale des Diamanten Geschichtliches Unsd Gegenwartiges. | Hamburg: Lenzen And Stormer., 39P. | India | Diamond Colour |
DS1960-1232 1969 | Yeremenko, G.K., Polkanov, YU.A. | Luminescence of Small Diamonds from Sandy Sediments of the Ukraine. | Doklady Academy of Science USSR, Earth Science Section., Vol. 188, No. 4, PP. 149-151. | Russia | Kimberlite, Photoluminescence, Colour |
DS1970-0707 1973 | Harris, J.W. | Observations on Letseng la Terae Diamonds | Maseru: Lesotho Nat. Dev. Corp. Lesotho Kimberlites Editor N, PP. 37-38. | Lesotho | Mineralogy, Morphology, Colour |
DS1981-0124 1981 | Cottrant, J.F., Calas, G. | Etude de la Coloration de Quelques Diamants du Museum National D'histoire Naturelle. | Rev. Gemmol. A.f.g., No. 67, PP. 2-5. | Global | Diamonds, Colour |
DS1982-0386 1982 | Malinko, S.V., Ilupin, I.P., Berman, I.B., Stoliarova, A.N. | Boron in Kimberlites of the Kuoika Field According to the Dat a of Local Radioagraphic Analysis. | Doklady Academy of Sciences AKAD. NAUK SSSR., Vol. 265, No. 1, PP. 170-172. | Russia | Spectrometry, Boron |
DS1983-0317 1983 | Huffer, H. | Fancy Diamonds Meld Colour and Brilliance | Jewellers Circular Keystone, Vol. 149, No. 12, PP. 33-40. | Global | Colour, Investment |
DS1984-0800 1984 | Zinchuk, N.N., Melnik, YU.M., Kharkiv, A.D. | First Ferroszaibelyite Finds in Kimberlitic Rocks #2 | Doklady Academy of Science USSR, Earth Science Section, Vol. 275, No. 1-6, pp. 103-107 | Russia | Mir Pipe, Boron, Mineral Chemistry |
DS1985-0291 1985 | Hofer, S.C. | Pink Diamonds from Australia | Gems And Gemology, Vol. 21, FALL PP. 147-155. | Global | Diamond Morphology, Colour, History, Spectral Analysis, Inclusions |
DS1985-0640 1985 | Springfield, J.T., Mansker, W.L. | Factors Affecting Garnet Metamerism and Applications in Kimberlite Evaluation/exploration. | Geological Society of America (GSA), Vol. 17, No. 3, P. 193. (abstract.). | Global | Garnet, Population, Mineral Chemistry, Colour |
DS1986-0276 1986 | Gems & Gemology | Natural color light green diamonds | Gems and Gemology, Vol. XXII Fall, p. 171 | Global | Diamond, Colour |
DS1986-0427 1986 | Kaye, D. | The rarest geM | Town and Country, Vol. 140, No. 5073, pp. 134-139, p. 177 | Global | Market, Coloured diamonds |
DS1987-0331 1987 | Kane, R.E. | Three notable fancy color diamonds: purplish red,purple-pink and reddishpurple | Gems and Gemology, Vol. 23, No. 2, Summer, pp. 90-95 | Brazil | Coloured diamonds |
DS1989-0448 1989 | Fritsch, E., Shigley, J.E. | Contribution to the identification of treated coloreddiamonds: diamonds with peculiar color zoned pavilions | Gems and Gemology, Vol. 25, No. 2, Summer pp. 95-101 | Global | Diamond morphology, Coloured diamonds |
DS1990-0465 1990 | Federman, D. | Fancy pink diamond -jet-set pet rock | Modern Jeweler, No. 3, March p. 40 | Australia | News item, Pink diamonds |
DS1990-1348 1990 | Shigley, J.E., Fritsch, E. | Optical properties of some natural color and laboratory treated color type1A green diamonds | International Mineralogical Association Meeting Held June, 1990 Beijing China, Vol. 2, extended abstract p. 687-688 | Global | Diamond morphology, Green diamonds |
DS1991-0905 1991 | Koivula, J.I., Kammerling, R.C. | Diamonds -colored diamonds at Tucson mineral show | Gems and Gemology, Gem News, Vol. XXVII, Spring p. 46 | Global | News item, Coloured diamonds |
DM1992-1787 1992 | Diamond International | Diamonds for connoisseurs | Diamond International, November/December pp. 56-65 | Global | Coloured diamonds, Market |
DS1992-0491 1992 | Fritsch, E., Scarratt, K. | Natural color nonconductive gray to blue diamonds | Gems and Gemology, Notes and new techniques, Vol. 28, Spring pp. 35-42 | Global | Diamond, Morphology, colour |
DS1992-0526 1992 | Gems & Gemology | Treated color diamonds with natural radiation stains | Gems and Gemology, Diamond laboratory Notes, Vol. 27, No. 4, pp. 249 | Global | Diamond morphology, Diamond colour |
DS1993-0496 1993 | Gem Trade Lab Notes | Brown-pink diamond with green graining | Gems and Gemology, Gem Trade Notes, Vol. 29, Fall, pp. 198-199. | Global | Diamond morphology, Colour |
DS1993-0497 1993 | Gem Trade Lab Notes | Light violet-gray diamond | Gems and Gemology, Gem Trade Notes, Vol. 29, Fall, pp. 199. | Global | Diamond morphology, Colour |
DS1993-0498 1993 | Gem Trade Lab Notes | Treated green diamond with a blue colour zone | Gems and Gemology, Gem Trade Notes, Vol. 29, Fall, pp. 200. | Global | Diamond morphology, Colour |
DS1993-1118 1993 | Nelson, J.B. | The glass filling of diamonds. Part 1. an explanation of the colourflashes. | Journal of Gemology, Vol. 23, No. 8, October pp. 461-472. | Global | Diamond morphology, Colour |
DS1994-0595 1994 | Gems & Gemology | Near colorless Russian synthetic diamond examined | Gems and Gemology, Vol. 30, Summer pp. 123, 124. | Russia | Diamond color, Synthetic diamonds |
DS1995-1735 1995 | Shigley, J.E. | A chart for the separation of natural and synthetic diamonds | Gems and Gemology, Vol. 31, Winter pp. 256-264. | Global | Diamond -synthetics, Diamond chart -classification, colour |
DS1995-1895 1995 | Testa, A. | Roses are red... diamonds are too | Australian Gold Gem and Treasure, Dec. p. 21. | Global | Diamond colour |
DM1995-2928 1995 | Town and Country | Change of heart... green diamonds changing colour | Town and Country Magazine, p. 44. | Angola | News item, Diamond colour |
DS1995-2108 1995 | You, C.F., Spivack, A.J., Gieskes, J.M., Rosenbauer | Experimental study of boron geochemistry: implications for fluid processes in subduction zones | Geochimica et Cosmochimica Acta, Vol. 59, No. 12, pp. 2435-2442 | Global | Geochemistry - experimental, Boron |
DS1996-0036 1996 | Anovitz, L.M., Grew, E.S. | Mineralogy, petrology and geochemistry of boron: an introduction | Reviews in Mineralogy, Vol. 33, pp. 1-40 | Global | Boron, Mineralogy |
DS1996-0503 1996 | Gems & Gemology Lab Notes | Different colors from the same rough | Gems and Gemology, Vol. 32, fall pp. 204-5. | Global | Diamond colours |
DS1996-0504 1996 | Gems & Gemology Lab Notes | Rare color: fancy intense pinkish orange | Gems and Gemology, Vol. 32, fall pp. 206. | Global | Diamond colours |
DS1996-0505 1996 | Gems & Gemology Lab Notes | A suite of treated color pink to purple diamonds | Gems and Gemology, Vol. 32, fall pp. 207-8. | Global | Diamond colours |
DS1996-0831 1996 | Leeman, W.P., Sisson, V.B. | Geochemistry of boron and its implications for crustal and mantleprocesses | Reviews in Mineralogy, Vol. 33, pp. 645-708 | Mantle | Boron, Geochemistry |
DS1996-1041 1996 | Noll, P.D. Jr., Newsom, H.E., Ryan, J.G. | The role of hydrothermal fluids in the production of subduction zonemagmas: evidence from siderophile .. | Geochimica et Cosmochimica Acta, Vol. 60, No. 4, Feb. 1, pp. 587-628 | Mantle | Geochemistry -chalcophile, boron, Subduction, magma, volcanics |
DS1996-1236 1996 | Ryan, J.G., Leeman, W.P., Morris, J.D., Langmuir, C.H. | The boron systematics of intraplate lavas: implications for crust and mantle evolution. | Geochimica et Cosmochimica Acta, Vol. 60, No. 3, Feb. pp. 415-422. | Mantle | Boron |
DS1997-0028 1997 | Anderson, B., Payne, J. | Absorption spectra of diamond | Gemstone Press, Spectroscope and Gemology, pp. 214-22. | Global | Diamond spectroscopy, History, colour |
DM1997-1416 1997 | Diamond International | Colour is tops... strong performance and preference | Diamond International, May June p. 35, 36. | United States | News item, Diamond colour |
DM1997-1446 1997 | Financial Post | Diamonds aren't always forever... Guillemards thought they owned two pink diamonds worth millions. | Financial Post, May 3, 3p. | Global | News item, Pink diamonds, De Beers |
DS1997-0375 1997 | Gemological Institute of America (GIA) Lab Notes | Diamond with " additional color".... rough with contrasting colors | Gems and Gemology, Vol. 33, Summer pp. 134-136. | Global | Diamond - color |
DS1997-0379 1997 | Gems & Gemology | Cathodluminescence of yellow diamonds | Gems and Gemology, Vol. 33, winter, pp. 298. | Global | Diamond - colour, Cathodluminescence |
DM1998-1758 1998 | Diamond News and South African Jeweller | The decade of colour.... defined niche in coloured diamonds | Diamond News and South African Jeweller, July pp. 15, 17. | Global | Diamond sales, Coloured diamonds |
DS1998-0485 1998 | Gemological Institute of America (GIA) Lab Notes | Diamond - color treated from orangy yellow to reddish purple....examination of before and after radiation. | Gems and Gemology, Fall pp. 213-4. | Global | Diamond - irradiation |
DS2000-0328 2000 | Gems & Gemology Lab Notes | Fancy white diamonds... rare .. | Gems and Gemology Lab Notes, Vol. 36, No. 2, Summer, p. 156. | Global | Diamond - colour |
DS2000-0329 2000 | Gems & Gemology Lab Notes | Blue, zoned diamond examined | Gems and Gemology Lab Notes, Vol. 36, No. 2, Summer, p. 156-7. | Global | Diamond - colour |
DS2000-0812 2000 | Reinitz, I.M., Buerki, P.R., Shigley, J.E., McClure | Identification of HPHT treated yellow to green diamonds. the saturated neon green colour is not only.. | Gems and Gemology, Vol. 36, No. 2, Summer, pp. 128-37. | United States, Russia, Sweden | Diamond - GE, Novatek, treated, colour |
DS2001-0202 2001 | Collins, A.T. | The colour of diamond and how it may be changed | Journal of Gemology, Vol. 27, No. 6, pp. 341-59. | Global | Diamond - morphology, colour |
DS2002-1098 2002 | Moses, T.M., King, J.M., Wang, W., Shigley, J.E. | A highly unusual 7.34 carat fancy vivid purple diamond | Journal of Gemmology, Vol. 28, January 1, pp. 7-12. | Global | Diamond - morphology, colour |
DM200412-2401 2003 | Gem News International | A comparison of three historic blue diamonds. Hope, Blue Heart, Heart of Eternity. | Gems & Gemology, Vol. 39, Winter, p. 322-325. | Technology | Diamonds notable - blue |
DS200412-0753 2004 | Gurney, J.J., Hildebrand, P.R., Carlson, J.A., Fedortchouk, Y., Dyck, D.R. | The morphological characteristics of diamonds from the Ekati property, Northwest Territories, Canada. | Lithos, Vol. 77, 1-4, Sept. pp. 21-38. | Canada, Northwest Territories | Diamond morphology, colour |
DM200412-2425 2004 | Idex Magazine | Black and brown diamonds. | Idex Magazine, June 22, 2p. | Technology | Diamond - colors |
DM200412-2426 2004 | Idex Magazine | Coveting the colored... diamonds. | Idex Magazine, June 22, 2p. | Technology | Diamond - colors |
DM200412-2427 2004 | Idex Magazine | Yellow - the king of color. | Idex Magazine, June 22, 2p. | Technology | Diamond - colors, yellow |
DM200412-2427 2004 | Idex Magazine | Yellow - the king of color. | Idex Magazine, June 22, 2p. | Technology | Diamond - colors, yellow |
DM200412-2428 2004 | Idex Magazine | Shades of a desert rose. | Idex Magazine, June 22, 2p. | Technology | Diamond - colors, pink |
DM200412-2428 2004 | Idex Magazine | Shades of a desert rose. | Idex Magazine, June 22, 2p. | Technology | Diamond - colors, pink |
DS200412-1375 2002 | Moses, T.M., King, J.M., Wang, W., Shigley, J.E. | A highly unusual 7.34 carat fancy vivid purple diamond. | Journal of Gemmology, Vol. 28, January 1, pp. 7-12. | Technology | Diamond - morphology, colour |
DS200512-0331 2005 | Gems & Gemology | HPHT treated IIa yellow diamond. | Gems & Gemology, Vol. 41, 1, Spring p. 43-46. | | Diamond - colour |
DS200512-0332 2005 | Gems & Gemology | Diamond - with body color possible affected by the 3H defect ( radiation). | Gems & Gemology, Vol. 41, 1, Spring p. 42-3. | | Diamond - colour |
DS200512-0387 2005 | Hainschwang, T., Katrusha, A., Vollstaedt, H. | HPHT treatment of different classes of type I brown diamonds. | Journal of Gemmology, Vol. 29, 5-6, pp. 261-273. | | Diamond - colour |
DS200512-0691 2005 | Massi, L., Fritsch, E., Collins, A.T., Hainschwang, T., Notari, F. | The amber centres and their relation to the brown colour in diamond. | Diamond and Related Materials, Vol. 14, 10, pp. 1623-1629. | Technology | Diamond color |
DS200612-0082 2006 | Bangert, U., Barnes, R., Hounsome, L.S., Jones, R., Blumenau, A.T., Briddon, P.R., Shaw, M.J., Oberg, S. | Electron energy loss spectroscopic studies of brown diamonds. | Philosophical Magazine, Vol. 86, no. 29/31, pp. 4757-4780. | Technology | Brown diamonds |
DM200612-1924 2006 | Diamonds.net | GIA to unveil authoritative book on coloured diamonds at symposium. | Diamonds.net, August 24, 1/2p. Cost $ 60.00 plus shipping) | Global | News item - book colored diamonds |
DS200612-0415 2006 | Fristch, E., Massi, L., Hainschwang, T., Collins, A.T. | The first color center related to the brown graining in type 1a natural diamonds. | International Mineralogical Association 19th. General Meeting, held Kobe, Japan July 23-28 2006, Abstract p. | Technology | Diamond H- colour |
DS200612-0437 2005 | Gems &.Gemology, Lab Notes | Strongly coloured natural type IIb blue diamonds. | Gems & Gemology, Vol. 41, 3, Fall, p.258-9.. | Technology | Diamond - colour |
DS200612-0438 2005 | Gems &.Gemology, Lab Notes | Diamond dyed rough. | Gems & Gemology, Vol. 41, 3, Fall, p.257-258. | Technology | Diamond - colour |
DS200612-0604 2006 | Hounsome, L.S., Jones, R., Martineau, P.M., Fisher, D., Shaw, M.J., Briddon, P.R., Oberg, S. | Origin of brown coloration in diamond. | Physical Review Letters, Vol. 73, 12, pp. 125203 ( 8 pages) | Technology | Diamond - colour |
DS200612-0831 2006 | Liu, Y. | Universal color grading system ( colored stones and diamonds). | GIA Gemological Research Conference abstract volume, Held August 26-27, p. 9, 1/2p. | Technology | Diamonds - colour CIELAB |
DS200612-1264 2006 | Severmish, M. | Color communication: the analysis of color in gem materials. ( Color stones and diamonds). | GIA Gemological Research Conference abstract volume, Held August 26-27, p. 9, 1/2p. | Technology | Diamonds - colour, ICC |
DS200612-1283 2006 | Shigley, J.F. | HPHT treated colorless and colored gem diamonds. | International Mineralogical Association 19th. General Meeting, held Kobe, Japan July 23-28 2006, Abstract p. | Technology | Diamond - colour, annealing |
DS200712-0160 2006 | Ceulemans, T. | Statistical study of the performance and predictive value of color measurement instruments for Cape coloured rough diamonds. | Gems & Gemology, 4th International Symposium abstracts, Fall 2006, p.130. abstract only | Technology | Diamond colour |
DM200712-1673 2007 | Diamonds.net | Celebrating brown - once the rejects of the industry - brown diamonds are now adored. | Diamonds.net, June 1, 2p. | Australia | News item - Brown diamonds |
DM200712-1674 2007 | Diamonds.net | Natural diamond colour change process earns patent. | Diamonds.net, July 11, 1/4p. | Technology | News item - brownish color |
DM200712-1675 2007 | Diamonds.net | Natural diamond colour change process earns patent. | Diamonds.net, July 11, 1/4p. | Technology | News item - brownish color |
DS200712-0283 2006 | Eaton-Magana, S., Post, J.E., Walters, R.A., Heaney, P.J., Butler, J.E. | Fluoresence of fancy color natural diamonds. | Gems & Gemology, 4th International Symposium abstracts, Fall 2006, p.131-2. abstract only | Technology | Diamond colour - UV radiation |
DS200712-0332 2007 | Fritsch, E., Rondeau, B., Hainschwang, T., Quellier, M.H. | A contribution to the understanding of pink color in diamond: the unique historical Grand Cond. | Diamond and Related Materials, Vol. 16, 8, pp. 1471-1474. | Technology | Diamond - colour |
DS200712-0333 2007 | Fritsch, E., Rondeau, B., Hainschwang, T., Quellier, M-H. | A contribution to the understanding of pink colour in diamond: the unique, historical 'Grand Conde'. | Diamond and Related Materials, Vol. 16, 8, August pp.1471-1474. | Technology | Diamond colour |
DM200712-2141 2006 | Gems & Gemology | Prolonged change of color in pink diamond exposure to UV radiation persisted for two weeks. | Gems & Gemology, Lab notes, Vol. 42, 4, winter pp. 263-264. | Technology | Diamond colour |
DM200712-2142 2006 | Gems & Gemology | Diamond Unusually large fancy white diamond with whitish banding. | Gems & Gemology, Lab notes, Vol. 42, 4, winter pp. 262-263. | Technology | Diamond colour |
DM200712-2202 2006 | Idex Online | Australia - gems from down under. Opal and sapphires featured. | Idex Magazine, Nov. 3p. | Australia | News item - coloured stones |
DS200712-0544 2006 | King, J.M., Moses, T.M., Wang, W. | The impact of internal whitish and reflective graining on the clarity grading of D to Z color diamonds at the GIA laboratory. | Gems & Gemology, Vol. 42, 4, winter pp. 206-221. | Technology | Diamond colour, grading |
DS200712-0547 2007 | Kitawaki, H. | Gem diamonds: causes of colors (NDFCT 536). | New Diamond and Frontier Carbon Technology, Vol. 17, 3, pp. 119-126. Ingenta | Technology | Diamond colour |
DS200712-0850 2006 | Pope, S. | High pressure, high temperature (HPHT) diamond processing: what is this technology and how does it affect colour? | Gems & Gemology, 4th International Symposium abstracts, Fall 2006, p.120, abstract only | Technology | Diamond color |
DS200712-0977 2007 | Shen, A.H., Wang, W., Hall, M.S., Novak, S., McClure, S.F., Shigley, J.E., Moses, T.M. | Serenity coated colored diamonds: detection and durability. | Gems & Gemology, Vol. 43, 1, Spring pp. 16-34. | Technology | Fancy diamonds |
DS200712-1003 2006 | Smirnov, S., Ananyev, S., Kalinia, V., Vins, V. | Color grading of color enhanced natural diamonds: a case study of Imperial red diamonds. | Gems & Gemology, 4th International Symposium abstracts, Fall 2006, p.126-7. abstract only | Technology | Colour grading |
DS200712-1070 2006 | Tashey, T.E.Jr., Tahey, M.C. | A system to describe the face up color appearance of white and off white polished diamonds. | Gems & Gemology, 4th International Symposium abstracts, Fall 2006, p.142-3. abstract only | Technology | Diamond colour grading |
DS200712-1099 2006 | Underwood, T. | Digital color communications for gemstones with an exploration of applications within our industry. | Gems & Gemology, 4th International Symposium abstracts, Fall 2006, p.143. abstract only | Technology | Diamond colour grading |
DS200812-0279 2008 | Deijanin, B., Simic, D., Zaitsev, A., Chapman, J., Dobrinets, I., Widemann, A., Del Re, N., Middleton, T., Dijanin, E., Se Stefano, A. | Characterization of pink diamonds of different origin: natural ( Argyle, non-Argyle), irradiated and annealed, treated with multi-process, coated and synthetic. | Diamond and Related Materials, Vol. 17, 7-10, pp. 1169-1178. | Australia | Pink diamonds |
DM200812-2228 2007 | Diamonds.net. | Mozambique imposes ban on gem trade. | Diamonds.net, Dec. 10, 1/4p. | Africa, Mozambique | News item - coloured stones |
DM200812-2491 2008 | Idex Magazine | Show me the color. Natural fancy diamond hue collection. | Idex Magazine, August 3, 5p. | Global | Coloured diamonds |
DM200812-2492 2008 | Idex Magazine | Colorwise retail. Socializing business and entertaining trust. | Idex Magazine, August 3, 3p. | Global | Coloured diamonds, gemstones |
DM200812-2500 2008 | Idex Magazine | Machine over man: coloring grading technology. | Idex Magazine, July 14, 5p. | Technology | Diamonds - colour |
DS200812-1176 2008 | Titkov, S.V., Shigley, J.E., Breeding, C.M., Mineeva, R.M., Zudin, N.G., Sergeev, A.M. | Natural color purple diamonds from Siberia. Mir field. | Gems & Gemology, Vol. 44, 1, spring pp. 56-64. | Russia, Siberia | Diamond - purple |
DM200912-1057 2009 | Colored Stone Magazine | Fancy these: inside the diamond color rainbow. ( green, yellow, purple and pink). | Colored Stone Magazine, Vol. 22, 4, July/August pp. 14-23. | Global | Diamond - colours |
DM200912-1058 2009 | Colored Stone Magazine | Singing the blues.... history of Hope. | Colored Stone Magazine, Vol. 22, 4, July/August pp. 36-41. | | Diamonds - blue |
DM200912-1059 2009 | Colored Stone Magazine | Techni-colors .. modern technology changes. | Colored Stone Magazine, Vol. 22, 4, July/August pp. 30-35. | Technology | Diamonds - coloured |
DS200912-0131 2009 | Cowing, M.D. | A place for CZ masters in diamond colour grading. | Journal of Gemmology, Vol. 31, 2-4, pp. 77-84. | Technology | Diamond colours |
DM200912-1385 2009 | Diamonds.net | Pink diamond treatment. | Diamonds.net, Feb. 1, 2p. | Technology | News item - coloured diamonds |
DM200912-1704 2008 | Diamonds.net | Rare red diamond on display at Los Angeles museum deemed priceless. Kazanjian Red. | Diamonds.net, Jan. 11, 1p. | Global | Diamonds notable - Kajanjian Red |
DM200912-1735 2008 | Diamonds.net | JVC launches essential guide to U.S. trade in color diamonds. | Diamonds.net, Dec. 23, 1p. | United States | News item - guide colour |
DS200912-0220 2009 | Fisher, D., Sibley, S.J., Kelly, C.J. | Brown colour in natural diamond and interaction between the brown related and other colour inducing defects. | Journal of Physics Condensed Matter, in press ( August) | Technology | Brown diamonds |
DM200912-1808 2009 | Gems & Gemology | Treated color pink diamonds. | Gems & Gemology Ebrief, Oct. 5, 1/8p. | Technology | Pink diamonds |
DS200912-0309 2009 | Holloway, G. | Blue fluoresence in diamonds. | Australian Gemmologist, Vol. 23, 9, 1p. | Technology | Diamond colour |
DS200912-0380 2008 | King, J.M., Geurts, R.H., Gilbertson, A.M., Shigley, J.E. | Color grading 'D-to-Z' diamonds at the GIA laboratory. | Gems & Gemology, Vol. 44, 4, pp. 296-321. | Technology | Diamond colours |
DS200912-0456 2009 | Lu, T., Odaki, T., Yasunaga, K., Uesugi, H. | A fancy reddish brown diamond with new optical absorption features. | Journal of Gemmology, Vol. 31, 2-4, pp. 73-76. | Technology | Diamond colour |
DS200912-0691 2009 | Shigley, J.E. | Coloured diamonds. | PDAC 2009, 1/2p. | Global | Diamonds - colours |
DS201012-0226 2010 | Gems & Gemology | Fancy vivid blue HPHT treated type IIb diamond. | Gems & Gemology Lab Notes, Vol. 46, 2, p. 141-142. | Technology | Diamond colour |
DS201012-0227 2010 | Gems & Gemology | Fancy vivid blue HPHT treated type IIb diamond. | Gems & Gemology Lab Notes, Vol. 46, 2, p. 141-142. | Technology | Diamond colour |
DM201012-1794 2010 | Idex Magazine | Tender loving: The Rio Tinto pink diamond tender. | Idex Magazine, April 28, 4p. | Australia | Argyle pink diamonds |
DM201012-1821 2010 | Idex Online | Sotheby's Hong Kong sale to include famed 5.16 ct Millenium Blue Diamond. | Idex Online, March 24, 1p. | Global | Diamonds notable - Millenium Blue |
DM201012-2196 2010 | National Post | Why it's worth - an estimated $ 8- 12$ million. Pink diamond. | National Post, Sept. 25, 1/2p. | Global | News item - pink diamond |
DS201012-0570 2010 | Payne, C., Bauer, R. | Differing causes of colour in diamonds. | The Australian Gemmologist, Vol. 24, 1, | Global | Diamond colours |
DM201112-1994 2011 | G & G eBrief | A rare fancy vivid purple diamond. | G & G Briefs, Oct. 4, 1/4p. | Technology | News item - diamond colour |
DM201112-1996 2011 | G & G eBrief | Pink diamond.... 21.73 ct. HPHT | G & G ebrief, Sept. 7, 1/4p. | Technology | News item - pink diamond |
DM201112-2376 2011 | Mining.com | A jaundiced view of the diamond market ( yellow diamonds featured at Christie's event) | Mining.com, Sept. 29, 1/2p. | Global | News item - diamond colour |
DS201112-0722 2011 | Nasdala, L. | Radio-coloration of diamond. | GIA International Symposium 2011, Gems & Gemology, Summer abstract p. 105. | Technology | Diamond color |
DM201112-2565 2011 | The Israeli Diamond Industry | Investing in fancy color diamonds. | israelidiamond.co.il, Sept. 5, 2p. | Global | News item - colour diamonds |
DM201112-2566 2011 | The Israeli Diamond Industry | Investing in fancy color diamonds. | israelidiamond.co.il, Sept. 5, 3p. | Technology | News item - coloured diamonds |
DM201112-2582 2011 | The Israeli Diamond Industry | Israel's fancy coloured diamond companies experience positive trend in 2010. | israelidiamond.co.il, Jan. 26, 2p. | Global | News item - diamond colour |
DM201112-2583 2011 | The Israeli Diamond Industry | Is it possible to detect color treatment in a diamond? | israelidiamond.co.il, August 8, 1p. | Technology | News item - diamond colour |
DS201112-1082 2011 | Vasilyev, E. | The nature of black coloration in gem quality diamonds. | GIA International Symposium 2011, Gems & Gemology, Summer poster abstract p. 135. | Technology | Diamond color |
DS201112-1102 2011 | Wang, W. | Review of diamond color treatment and its identification. | GIA International Symposium 2011, Gems & Gemology, Summer abstract p. 107. | Technology | Diamond color |
DM201205-1328 2012 | Edmonton Journal | Buyers for $ 2.5 million diamond as rare as the giant gems. 10 carat pink diamond | Edmonton Journal, April 13, 1p. | Global | News item - pink diamond |
DM201207-1617 2012 | The Israeli Diamond Industry | Fancy colored diamonds touted as investments. | israelidiamond.co.il, June 12, 1/4p. | Global | News item - coloured diamonds |
DS201212-0013 2012 | Almor, Y. | Who's afraid ofirradiated diamonds? | Hayashalom Magazine, No. 207, pp. 157- | Technology | Diamond - irradiation |
DS201212-0100 2012 | Byrne, K.S., Anslie, J.D., Chapman, J.G., Luiten, A.N. | Optically reversible photochromism in natural pink diamond. | Diamond and Related Materials, Vol. 30, pp. 31-36. | Technology | Diamond colour |
DS201212-0195 2012 | Farges, F., Vinson, J., Rehr, J.R., Post, J.E. | Spectroscopy of B doped diamonds: experiment vs. theory. Hope, Tavernier Blue, French Blue | emc2012 @ uni-frankfurt.de, 1p. Abstract | Technology | Diamond - colour |
DS201212-0222 2012 | G & G ebrief | Diamond basics: part 3: how color happens in diamonds. | G & G Brief, Vol. 4, 2, Nov. 14, 1/4p. | Technology | Diamond colour |
DS201212-0225 2012 | Gaillou, E.,Post, J.E., Rost, D., Butler, J.E. | Boron in natural type 11b blue diamonds: chemical and spectroscopic measurements. | American Mineralogist, Vol. 97, pp. 1-18. | Technology | Blue diamond |
DS201212-0545 2012 | Payne, C., Bauer, R. | Causes of colour in fancy white diamonds. | The Australian Gemmologist, Vol. 24, 9, Jan-Mar. pp. | Technology | Diamond - colour |
DM201305-1577 2013 | Diamond Investing News | Brown diamonds set to be the next big thing. | Diamond Investing News, April 1, 2p. | Global | News item - Brown diamonds |
DM201306-1775 2013 | Diamonds.net | NCDIA plans a brown diamond conference for October. GIA education centre National Color Diamond Association | Diamonds.net, May 22, 1/2p. | Global | News item - brown diamonds |
DM201309-2308 2013 | Rough-Polished | Sotheby's to auction rare blue diamond. | rough-polished.com, August 20, 1/4p. | Technology | News item - blue diamond |
DM201310-2418 2013 | Rough-Polished | What for were diamonds made coloured. | rough-polished.com, Sept. 4, 1/4p. | Technology | News item - diamond colors |
DS201312-0287 2013 | G & G ebriefs | Artificially irradiated brown diamond. | Gems & Gemology, 1/2p. | Technology | Diamond - colour |
DS201312-0302 2013 | Gem Lab Notes | Strong color zoning reflects complex growth environment… orangy brown type IA | Gems & Gemology, Lab notes p. 116. | Technology | Diamond - colour |
DS201312-0341 2013 | Guagliardo, P., Byrne, K.,Chapman, J.,Sudarshan, K., Samarin, S., Williams, J. | Positron annihilation and optical studies of natural brown type 1 diamonds. | Diamond and Related Materials, Vol. 37, pp. 37-40. | Technology | Brown diamonds |
DS201312-0352 2013 | Hainschwang, T., Fritsch, E., Notari, F., Rondeau, B., Katrusha, A. | The origin of color in natural C center bearing diamonds. | Diamond and Related Materials, Vol. 39, pp. 27-40. | Technology | Diamond colour |
DS201312-0557 2013 | Luo, Y., Breeding, C.M. | Fluorescence produced by optical defects in diamond: measurement, characterization, and challenges. | Gems & Gemology, Vol. 49, 2, Summer pp. 82-97. | Technology | Diamond colour - spectra |
DS201312-0637 2013 | Nasdala, L., Grambole, D., Wildner, M., Gigler, A.M., Hainschwang, T., Zaitsev, A.M., Harris, J.W., Milledge, J., Schulze, D.J., Hofmeister, W., Balmer, W.A. | Radio-colouration of diamond: a spectroscopic study. | Contributions to Mineralogy and Petrology, Vol. 165, pp. 843-861. | Africa, South Africa, Democratic Republic of Congo, South America, Brazil, Venezuela | Diamond - colour |
DS201312-0809 2013 | Shepherd, P. | Overview of presentation on colour in diamonds. | London Ontario Mineral and Gem Society, 1p. Abstract | Technology | Diamond - colour |
DS201312-0813 2013 | Shigley, J.E., Breeding, C.M. | Optical defects in diamond: a quick reference chart. | Gems & Gemology, Vol. 49, 2, Summer pp. 107-111. | | Diamond colour - spectra |
DM201403-1251 2014 | Diamond Investing News | Rav Dhillon talks colored diamond sourcing, investing and jewelery. | Diamond Investing News, Feb. 6, 1p. | Technology | News item - coloured diamonds |
DM201403-2480 2014 | The Israeli diamond industry | Fancy diamond color grading. | israelidiamond.co.il, Feb. 2, 3p. | Technology | Diamonds - coloured |
DM201412-1526 2014 | Diamonds.net | Fancy color diamonds identified as stable, high growth alternative asset class. | Diamonds.net, Nov. 12, 1/4p. | Global | News item - coloured diamonds |
DS201412-0260 2014 | Gaillou, E., Rossman, G.R. | Color in natural diamonds: the beauty of defects. | Rocks and Minerals, Jan-Feb. pp. 66-75. | Technology | Diamond - colour |
DS201412-0261 2014 | Galillou, E., Post, J.E., Steele, A., Butler, J.E. | Constrains on highly strained pink diamonds by high spatial resolution FTIR and Raman mapping. | Geological Society of America Conference Vancouver Oct. 19-22, 1p. Abstract | Technology | Pink diamond colour |
DS201412-0376 2014 | Howell, D. | Pink colour in Type 1 diamonds: is deformation twinning the cause? | ima2014.co.za, Poster | Technology | Diamond - color |
DM201412-2433 2014 | Rough-Polished | Fancy colours remain a niche category for which awareness and demand is yet to be strongly created says Shantakumar. | rough-polished.com, Nov. 17, 1/4p. | Global | News item - coloured diamonds |
DS201412-0808 2014 | Shigley, J.E. | Causes of color in diamonds. | 6 Simposio Brasileiro de Geologia do Diamante, Aug. 3-7, 1p. Abstract | Technology | Diamond colour |
DM201412-2534 2014 | The Israeli Diamond Industry | New price index shows pink diamonds have the biggest growth among fancy colored. | israelidiamond.co.il, Nov. 13, 1/4p. | Technology | News item - pink diamonds |
DM201503-1102 2015 | Rough-Polished | Fancy coloured diamond index reflects stable prices in Q4 2014. | rough-polished.com, Feb. 19, 1/4p. | Global | News item - colored diamonds |
DM201503-1348 2015 | The Israeli Diamond Industry | The mystery that still baffles scientists: what makes pink diamonds pink? | israelidiamond.co.il Blog Stonehicky, Jan. 1, 1/4p. | Australia | News item - pink diamonds |
DS201503-0180 2015 | Titkov, S.V., Mineeva, R.M., Zudina, N.N., Sergeev, A.M., Ryabchikov, I.D., Shiryaev, A.A., Speransky, A.V., Zhikhareva, V.P. | The luminescent nature of orange coloration in natural diamonds: optical and EPR study. | Physics and Chemistry of Minerals, Vol. 42, 2, pp. 131-144. | Technology | Diamond Colour |
DS201506-0295 2015 | Shigley, J.E., Breeding, C.M. | Visible absorption spectra of colored diamonds. | Gems & Gemology, Vol. 51, 1, pp. 41-43. | Technology | Coloured diamonds |
DS201507-0311 2015 | Even-Zohar, C. | Temporary color enhancement: a potential game changer for industry and grading labs. | Diamond Intelligence Briefing ( Courtesy of Chaim), Vol. 30, no. 857, May 28, 8p. | Technology | Diamond - colours |
DS201508-0354 2015 | Even-Zohar, C. | Temporary colour enhancement …. Treatment, story so far, timing, legal and commercial problems of dishonesty. | Idex Magazine, No. 303, July pp. 36-62. | Technology | Diamond color enhancement |
DM201509-0750 2015 | Diamonds.net | Blue diamonds drive color index higher in 2Q. Fancy Color diamond index ( FCDI tm) | Diamonds.net, Aug. 25, 1/4p. | Global | News item - Blue diamonds |
DM201510-2043 2015 | Idex Memo | Betting on color…. Minion yellow. | Idexonline, Sept. 24, 1p. | Technology | News item - diamond colour |
DS201511-1866 2014 | Payne, C., Bauer, R. | Differing causes of colour in diamonds. | Australian Gemmologist, Vol. 24, 1, pp. 15-16. | Technology | Diamond colour |
DS201603-0374 2016 | Eaton-Magana, S.C., Moe, K.S. | Temperature effects on radiation stains in natural diamonds. | Diamond and Related Materials, in press available 29p. | Technology | Green diamonds |
| Abstract: The green coloration of natural diamonds typically results from exposure to natural irradiation. This creates the GR1 optical center and in many diamonds, surficial damage, principally due to alpha radiation, which helps verify natural origin. In this study, 13 naturally irradiated diamonds with pronounced radiation stains were stepwise annealed from 200 °C to 1400 °C and the changes in color and defects were documented by photomicrography and spectroscopy. Additionally 3 diamonds were subjected to isothermal annealing at 550 °C. The radiation stains correlated with radiation-damage Raman peaks — a broad and shifted diamond Raman peak and radiation-related peaks at 1500 and 1640 cm? 1. The color transitioned from green to brown after heating to 550-600 °C and the stains were essentially decolorized at 1400 °C. Confocal Raman depth profiling showed that the depth penetration of the radiation stain was about 10-15 ?m into the diamond and this depth profile was distinctly different from depth profiles of ion-irradiation stains generated in a laboratory. |
DM201603-0573 2016 | Rough-Polished | Fancy color diamond prices stable year on year following turnaround for yellow diamonds in Q4. | rough-polished.com, Feb. 15, 1/4p. | Global | News item - coloured diamonds |
DM201606-1184 2016 | Ehud Arye Laniado | All about fancy coloured diamonds: introduction. | [email protected], May 25, 4p. | Technology | News item - colored diamonds |
DM201607-2566 2016 | Ehud Arye Laniado | All about color diamonds. | info@laniado, June 1, 4p. | Technology | News item - colour diamonds |
DM201607-2569 2016 | Ehud Arye Laniado | The growing rareness of pink diamonds. | info@laniado, June 15, 7p. | Australia | News item - pink diamonds |
DM201607-2571 2016 | Ehud Arye Laniado | Green diamonds - unique and challenging. | info@laniado, June 22, 6p. | Technology | News item - green diamonds |
DM201607-1539 2016 | Rough-Polished | Fancy color diamond book set to transform the diamond buying process. | rough-polished.com, June 29, 1/4p. | Technology | News item - colour diamonds |
DM201608-1510 2016 | Ehud Arye Laniado | Champagne, cognac, chocolate and brandy: how the industry markets brown diamonds. | info @laniado.com, July 6, 4p. | Global | News item - champagne diamonds |
DM201608-1511 2016 | Ehud Arye Laniado | Gray diamonds. | info @laniado.com, July 13, 2p. | Technology | News item - gray diamonds |
DM201609-1767 2016 | Diamonds.net | Blue diamonds buoy fancy color prices. | Diamonds.net, Aug. 15, 1/4p. | Technology | News item - Blue diamonds |
DM201609-1776 2016 | Ehud Arye Laniado | Fancy color diamond price direction. | info @ehudlaniado.com, Aug. 15, 6p. | Technology | News item - color prices |
DM201609-1781 2016 | Idex Magazine | A bumper year for colored diamonds at auction. | Idex Magazine, Vol. 30, 316, Aug. pp. 26-34. | Global | News item - coloured diamonds |
DS201610-1900 2016 | Post, J.E., Gaillou, E., Butler, J.E., Byrne, K.S. | Investigations into the luminescence properties and compositions of colored diamonds. ( blue and pink) | GSA Annual Meeting, 1/2p. abstract | Technology | Coloured diamonds |
| Abstract: The Smithsonian’s National Gem Collection includes the Hope Diamond and an assortment of other significant fancy-colored diamonds, providing a unique opportunity to conduct detailed and sustained studies on an unprecedented selection of these rare and valuable stones. We present an overview and recent results from our work on pink, blue and chameleon diamonds. Boron causes the blue color of the Hope Diamond and other type IIb diamonds, but scarcity, high value, and the low concentration of B has inhibited B analyses of natural IIb diamonds. We used FTIR and ToF-SIMS to measure concentrations and distributions of B in the Hope and other blue diamonds. ToF-SIMS analyses gave spot B concentrations as high as 8.4 ± 1.1 ppm for the Hope Diamond to less than 0.08 ppm in other blue diamonds and revealed strong zoning of B in some diamonds, which was confirmed by mapping using synchrotron FTIR. Boron is also responsible for the phosphorescence emissions of IIb diamonds, at 660 nm and 500 nm; the emissions are likely caused by donor-acceptor pair recombination processes involving B and other defects. Approximately 50 type I natural pink diamonds were compared using UV-Vis, FTIR, and CL spectroscopies. All stones exhibit pink color zoning, ~1µm thick [111] lamellae, in otherwise colorless diamond. The pink diamonds fall into two groups: 1) those from Argyle in Australia and Santa Elena in Venezuela, and 2) those from other localities. TEM imaging from FIB sections revealed that twinning is the likely mechanism by which plastic deformation is accommodated for the pink diamonds. The deformation creates new centers, including the one responsible for the pink color, which remains unidentified. The differences in the plastic deformation features for the two groups might correlate to the particular geologic conditions under which the diamonds formed. Fluorescence and thermoluminescence experiments on natural chameleon diamonds reveal that an emission band, peaking near 556nm, may be stimulated via a number of different mechanisms. We discuss the implications of our observations for the electronic structure of the 556nm-fluorescing defect center, and the connections to the unidentified color center responsible for chameleon color changes. |
DM201612-2404 2016 | Idex online | Demand for natural blue diamonds drives color stone price in Q3. | Idexonline, Nov. 10, 1/4p. | Technology | News item - Blue diamonds |
DM201701-0161 2016 | The Israeli Diamond Institute | Rare and special: 8 fascinating facts about natural purple diamonds. Hydrogen | israelidiamond.co.il, Dec. 23, 1p. | Technology | News item - colour |
DS201705-0827 2017 | Gaillou, E., Rossman, G.R. | On the Beauty of Defects. | lithographie.org, No. 19, pp. 40-53. | Technology | Book - diamond colour |
| Abstract: Extensive study has shown that these inclusions contain mantle-derived fluids (e.g. Navon et al., 1988, Izraeli et al., 2001, 2004 Tomlinson et al., 2009; Logvinova et al., 2011; Zedgenizov et al., 2011; Smith et al., 2012, Smith et al., 2015 Howell et al., 2012b Howell et al., , 2013 Weiss et al., 2013 Weiss et al., , 2015 Rakovan et al., 2014; Smit et al., in press), Here we use the term 'milky' to describe diamonds that contain zones of opalescent to brown or grey opaque appearance (Gaillou and Rossman, 2014). The exact cause of this opacity is yet to be defined, and forms the purpose of this paper. |
DM201705-1015 2017 | Rough-polished | Fancy colour diamond price index slightly up in Q1 2017. | rough-polished.com, April 29, 1/4p. | Global | News item - fancy color |
DM201706-1173 2017 | Geology In | Pink diamond mystery solved: what makes pink diamonds pink? | geologyin.com, May 5, 1p. | Technology | News item - pink diamonds |
DM201803-0516 2018 | Diamonds.net | Blues up, pinks down in 2017 index. Yellow diamonds dip, but still better than previous year. | diamonds.net, Feb. 5, 1/4p. | Global | News item - blue diamonds |
DS201804-0675 2018 | Breeding, M. | Diamond defects, diamond colour treatment, and its identification. | 4th International Diamond School: Diamonds, Geology, Gemology and Exploration Bressanone Italy Jan. 29-Feb. 2nd., pp. 11-13. abstract | Technology | diamond -color centers |
DM201805-1052 2018 | Diamonds.net | Rosy future: investing in pink diamonds. Argyle | diamonds.net, Apr. 11, 3p. | Australia | News item - pink diamonds |
DS201806-1214 2018 | Breeding, C.M., Eaton-Magana, S., Shigley, J.E. | Natural color green diamonds: a beautiful conundrum. | Gems& Gemology, Vol. 54, 1, spring pp. 2-27. | South America, Brazil, Venezuela, Guyana | diamonds - green review |
| Abstract: Among fancy-color diamonds, natural-color green stones with saturated hues are some of the rarest and most sought after. These diamonds are colored either by simple structural defects produced by radiation exposure or by more complex defects involving nitrogen, hydrogen, or nickel impurities. Most of the world’s current production of fine natural green diamonds comes from South America or Africa. Laboratory irradiation treatments have been used commercially since the late 1940s to create green color in diamond and closely mimic the effects of natural radiation exposure, causing tremendous difficulty in gemological identification. Compounding that problem is a distinct paucity of published information on these diamonds due to their rarity. Four different coloring mechanisms—absorption by GR1 defects due to radiation damage, green luminescence from H3 defects, and absorptions caused by hydrogen- and nickel-related defects—can be identified in green diamonds. Careful microscopic observation, gemological testing, and spectroscopy performed at GIA over the last decade allows an unprecedented characterization of these beautiful natural stones. By leveraging GIA’s vast database of diamond information, we have compiled data representative of tens of thousands of samples to offer a look at natural green diamonds that has never before been possible. |
DM201808-1841 2018 | Diamonds.net | NCDIA releases video on yellow diamonds. | diamonds.net, July 2, 1/4p. | Global | News item - NCDIA |
DS201809-2005 2017 | Cassette, P., Notari, F., Lepy, M-C., Caplan, C., Pierre, S., Hainschwang, T., Fritsch, E. | Residual radioactivity of treated green diamonds. | Applied Radiation and Isotopes, Vol. 126, 1, pp. 66-72. | Global | diamond - green |
| Abstract: Treated green diamonds can show residual radioactivity, generally due to immersion in radium salts. We report various activity measurements on two radioactive diamonds. The activity was characterized by alpha and gamma ray spectrometry, and the radon emanation was measured by alpha counting of a frozen source. Even when no residual radium contamination can be identified, measurable alpha and high-energy beta emissions could be detected. The potential health impact of radioactive diamonds and their status with regard to the regulatory policy for radioactive products are discussed. |
DM201809-2161 2018 | Diamonds.net | Blue leads fancy coloured prices. | diamonds.net, Aug. 6, 1/4p. | Global | News item - blue diamonds |
DS201809-2017 2018 | Eaton-Magana, S., Breeding, C.M., Shigley, J.E. | Natural color blue, gray, and violet diamonds: allure of the deep. | Gems & Gemology, Vol. 54, 2, pp. 112-131. | Africa, South Africa, Australia | diamond - colour |
| Abstract: Natural-color blue diamonds are among the rarest and most valuable gemstones. Gray and violet diamonds are also included here, as these diamonds can coexist on a color continuum with blue diamonds. More so than most other fancy colors, many diamonds in this color range are sourced from specific locations-the Cullinan mine in South Africa and the Argyle mine in Australia. Although blue color is often associated with boron impurities, the color of diamonds in this range (including gray and violet) also originates from simple structural defects produced by radiation exposure or from more complex defects involving hydrogen. These different mechanisms can be characterized by absorption and luminescence spectroscopy. A fourth mechanism-micro-inclusions of grayish clouds or tiny graphite particles in gray diamonds-can be distinguished through microscopy. In this article, we summarize prior research as well as collected data such as color and carat weight on more than 15,000 naturally colored blue/gray/violet diamonds from the GIA database (along with an analysis of spectroscopic data on a subset of 500 randomly selected samples) to provide an unprecedented description of these beautiful gemstones. |
DS201809-2030 2018 | Green, C. | The pursuit of colour. Part 1. The rise to prominence of fancy coloured diamonds post 1970. | The Australian Gemmologist, Vol. 26, 9-10, pp. 226-239. | Global | diamond - colour |
DM201810-2431 2018 | Diamonds.net | Rosy outlook: Christie's ten history making pink diamonds sold at Christie's. | diamonds.net, Sept. 12, 1/4p. | Global | News item - pink diamonds |
DS201811-2569 2018 | Ekimov, E.A., Sidorov, V.A., Maslakov, K.I., Sirotinkin, B.P., Krotova, M.D., Pleskov, Yu.V. | Influence of growth medium composition on the incorporation of boron in HPHT diamond. | Diamond & Related Materials, Vol. 89, pp. 101-107. | Mantle | boron |
| Abstract: Influence of growth medium composition on the efficiency of boron doping of carbonado-like diamond at 8-9 GPa was studied by diluting the C-B growth system with metallic solvents of carbon, Co and Ni. Addition of these metals to the original system leads to a decrease in the synthesis temperature, degree of doping with boron and suppression of superconductivity in diamond. According to XPS analysis, content of substitutional boron is equal to 0.07, 0.16 and 0.39 at.% in diamonds obtained in Co-C-B, Ni-C-B and C-B growth systems, respectively. Metallic behavior at normal temperatures and superconductivity below 5 K in diamond, synthesized in C-B system, change to semiconducting character of conductivity down to 2 K in diamonds obtained in the diluted systems; a faint hint of superconducting transition at 2 K was detected in the case of diamond grown in Ni-C-B system. By comparing phase composition of the inclusions and the doping efficiency of the diamonds, we are able to suggest that high chemical affinity of boron to boride-forming metals hinders the boron doping of diamond. The heavily boron-doped carbonado-like diamond compacts demonstrate high electrochemical activity in aqueous solutions and can be used as miniature electrodes in electrosynthesis and electroanalysis. |
DM201811-2730 2018 | South China Morning Post | Will green diamonds become a China investor's best friend? | southchinamorningpost.com, Oct. 8, 1/2p. | China | News item - green diamonds |
DM201812-2956 2018 | Diamonds.net | Prices rise for pink and blue diamonds. | diamonds.net, Nov. 1, 1/4p. | Global | News item - pink diamonds |
DS201901-0009 2018 | Breeding, C.M. | Colored diamonds: the rarity and beauty of imperfection. | Gems & Gemology, Sixth International Gemological Symposium Vol. 54, 3, 1p. Abstract p. 275. | Global | diamond color |
| Abstract: Diamond is often romanticized as a symbol of purity and perfection, with values that exceed all other gemstones. However, even the most flawless and colorless natural diamonds have atomic-level imperfections. Somewhat ironically, the rarest and most valuable gem diamonds are those that contain abundant impurities or certain atomic defects that produce beautiful fancy colors such as red, blue, or green—stones that can sell for millions of dollars per carat. Atomic defects can consist of impurities such as nitrogen or boron that substitute for carbon atoms in the diamond atomic structure (resulting in classifications such as type Ia, type Ib, type IIa, and type IIb) or missing or misaligned carbon atoms. Some defects are created during diamond growth, while others are generated over millions to billions of years as the diamond sits deep in the earth at high temperatures and pressures. Defects may be created when the diamond is rapidly transported to the earth’s surface or by interaction with radioactive fluids very near the earth’s surface. Each defect selectively absorbs different wavelengths of light to produce eye-visible colors. Absorptions from these color-producing defects (or color centers) are detected and identified using the gemological spectroscope or more sensitive absorption spectrometers such as Fouriertransform infrared (FTIR) or ultraviolet/visible/near-infrared (UV-Vis-NIR; figure 1). Some defects not only absorb light but also produce their own luminescence, called fluorescence. For example, the same defect that produces “cape” yellow diamonds also generates blue fluorescence when exposed to ultraviolet light. In some cases, the fluorescence generated by defects can be strong enough to affect the color of gem diamonds. With the exception of most natural white and black diamonds, where the color is a product of inclusions, colored diamonds owe their hues to either a single type of defect or a combination of several color centers. More than one type of defect can produce a particular color, however. Table 1 provides a list of the most common causes of color in diamond. Subtle differences in atomic defects can drastically affect a diamond’s color. For example, isolated atoms of nitrogen impurities usually produce strong yellow color (“canary” yellow diamonds). If those individual nitrogen atoms occur together in pairs, no color is generated and the diamond is colorless. If instead the individual nitrogen atoms occur adjacent to missing carbon atoms (vacancies), the color tends to be pink to red. Rearrangement of diamond defects is the foundation of using treatments to change the color of diamond. Identification of treatments and separation of natural and synthetic diamond requires a thorough understanding of the atomic-level imperfections that give rise to diamond color and value. |
DS201901-0011 2018 | Butler, J.E., Byrne, K.S., Wang, W., Post, J.E. | Complex charge transfer in chameleon diamonds: a model of the color-change process, | Gems & Gemology, Sixth International Gemological Symposium Vol. 54, 3, 1p. Abstract p. 303. | Global | diamond color |
| Abstract: A group of natural diamonds known as chameleon diamonds change color from green to yellow based on their exposure to light and heat. These diamonds also emit long-lived phosphorescence after UV excitation. We have observed the optical response of these diamonds to optical and thermal excitation and developed a model to explain the observed phenomena. A principal element of the model is the proposal of an acceptor state (figure 1), which should be observable in the near-infrared (NIR) region. Subsequently, we have observed the NIR absorption to this acceptor state, supporting our model of charge-transfer processes in these diamonds. |
DS201901-0019 2018 | Cohen, H., Ruthstein, S. | Evaluating the color and nature of diamonds via EPR spectroscopy. | Gems & Gemology, Sixth International Gemological Symposium Vol. 54, 3, 1p. Abstract p. 276. | Global | diamond color |
| Abstract: Diamond characterization is carried out via a wide variety of gemological and chemical analyses. An important analytical tool for this purpose is spectroscopic characterization utilizing both absorption and emission measurements. The main techniques are UV-visible and infrared spectroscopy, though Raman as well as cathodoluminescence spectroscopy are also used. We have used electron paramagnetic resonance (EPR) spectroscopy to compare the properties of treated colored diamonds to the pretreated stones. The colors studied were blue, orange, yellow, green, and pink. The EPR technique determines radicals (atoms with unpaired electrons) and is very sensitive, capable of measuring concentrations as low as ~1 × 10–17 radicals/cm3. The results, shown in table 1, indicate that all the carbon radicals determined are affected by adjacent nitrogen atoms, with the spectra showing a hyperfine structure attributed to the presence of nitrogen. The highest concentration of radicals and hyperfine structures is observed in pink and orange treated diamonds. The results concerning nitrogen concentration were correlated with the infrared spectra, which determine the absorption peaks of the diamonds as well as those of the nitrogen contamination in their crystal structure. |
DS201901-0049 2018 | Odake, S. | Melee diamonds: metal defects and treated color. | Gems & Gemology, Sixth International Gemological Symposium Vol. 54, 3, 1p. Abstract p. 304. | Global | diamond color |
| Abstract: Gem-quality laboratory-grown diamonds are manufactured in large quantities. With frequent reports of the mixing of meleesized synthetic diamonds with natural stones, demand for melee diamond screening is increasing. During melee diamond screening at GIA’s Tokyo lab, two notable types of samples with uncommon characteristics have been found. 1. Natural melee diamonds with silicon and nickel defects. Luminescence peaks derived from Si- and Ni-related defects are often observed in colorless melee grown by the HPHT method. The silicon-related defect, once considered proof of CVD-grown diamond, is now known to exist naturally as well (Breeding and Wang, 2008). Several colorless melee diamonds having both silicon- and nickel-related emissions have been found in GIA’s Tokyo lab; olivine inclusions were found in one of these samples. Spectroscopic and gemological features confirmed that the samples were grown in nature. 2. Irradiated laboratory-grown diamond melee found among irradiated natural melee diamonds. Several thousand greenish blue melee diamonds have been submitted by various clients to the Tokyo lab for testing. Each diamond’s color was attributed to a strong GR1 defect caused by irradiation treatment. Fourier-transform infrared (FTIR), photoluminescence (PL), and DiamondView analysis revealed that most of them were irradiated natural diamonds. Eight were irradiated CVD-grown diamonds, and one was an irradiated HPHT-grown specimen. The infrared spectrum of all the CVD samples showed a peak at 3123 cm-1, while their PL spectrum showed a doublet peak at 596/597 nm. Those peaks are specific to as-grown CVD diamonds, as annealing removes the peaks. From their spectra, these CVD specimens were considered irradiated without pre-annealing. |
DS201901-0074 2018 | Serov, R. | Quantitative absorption spectrum reconstruction for polished diamond. | Gems & Gemology, Sixth International Gemological Symposium Vol. 54, 3, 1p. Abstract p. 276-7. | Global | diamond color |
| Abstract: Natural diamonds generally exhibit a very wide range of spectra. In polished stones, absorption along with proportions and size define perceived diamond color and thus beauty. In rough diamonds, the quantitative absorption spectrum (the “reference spectrum” in the context of this article) can be measured using an optical spectrometer through a set of parallel windows polished on a stone, so the diamond can be considered a planeparallel plate with known thickness. Polished diamonds lack the parallel facets that might allow plane-parallel plate measurement. That is why polished diamond colorimetry uses one of two approaches that have certain limitations for objective color estimation: 1) Qualitative spectrum assessment with an integrating sphere. Suppose three diamonds are polished from a yellow rough with even coloration: a round (with short ray paths), a cushion (with high color uniformity and long ray paths), and a “bow tie” marquise (with both long and short ray path areas). The spectra captured from these three stones by an integrating sphere will be completely different because the ray paths are very different. However, the quantitative absorption spectrum will be the same for all three stones, since they are cut from the same evenly colored rough. Therefore, spectrum assessment with an integrating sphere has very limited accuracy and is practical for qualitative estimations only. 2) Analysis of multiple images of a diamond made by color RGB camera. This method has low spectral resolution defined by digital camera color rendering. The camera has a smaller color gamut than the human eye, so most fancycolor diamonds are outside the color-capturing range of a digital camera. However, quantitative absorption data is very valuable for: 1) Color prediction and optimization for a new diamond after a recut process 2) Objective color assessment and description of a polished diamond This paper presents a new technology based on spectral lightemitting diodes (LEDs) and high-quality ray tracing, which together allow the reconstruction of a quantitative absorption spectrum for a polished diamond. The approach can be used for any transparent polished diamond. The recent technology prototype has a resolution of 20–60 nm, which is practical for color assessment. Figure 1 (top) presents three photorealistic diamond images: A is based on the reconstructed absorption spectrum collected from a polished diamond, B uses the reference spectrum collected in the rough stage through a pair of parallel windows, and C uses the averaged reference spectrum. Figure 1 (bottom) shows both measured quantitative absorption and reconstructed absorption spectra. This technology has the potential to ensure very close to objective color estimation for near-colorless and fancy-color polished diamonds. The reconstructed spectrum resolution can be enhanced to 10–15 nm in future devices. |
DM201902-0340 2019 | Barrons | Colored diamonds expected to shine in 2019. | barrons.com, Jan. 4, 1p. | Global | News item - diamond colour |
DM201902-0366 2018 | Diamonds.net | Pink diamonds: how the pink diamond became one of the world's hottest gems. | newyorkpost.com, Dec. 31, 1/4p. | Global | News item - diamond colour |
DS201903-0505 2018 | Eaton-Magana, S., Ardon, T., Smit, K.V., Breeding, C.M., Shigley, J.E. | Natural color pink, purple, red and brown diamonds: band of many colors. | Gems & Gemology, Vol. 54, 4, pp. 352-377. | Global, Australia | diamond colour |
| Abstract: Diamond is one of Earth’s most extraordinary materials. It represents the pinnacle for several material and physical properties. As a gem, however, it is the near-perfect examples—diamonds attaining the D-Flawless distinction—and those with imperfections resulting in a vibrant or surprising color that create the most enduring impressions. Fancy-color natural diamonds are among the most highly valued gemstones due to their attractiveness and great rarity. The 18.96 ct Winston Pink Legacy, with a color grade of Fancy Vivid pink, recently made history by selling at over $50 million, its $2.6 million per carat price an all-time high for a pink diamond (Christie’s, 2018). |
DM201903-0587 2019 | Ehud Arye laniado | Diamond industry Organizations: International Colored Gemstone Association. | info@ ehudlaniado.com , Feb. 20, 2p. | Global | News item - ICA |
DS201903-0538 2018 | Pay, D. | Pink diamonds and more | Gems & Gemology, Vol. 54, 4, p. 351. | Global | diamond color |
DM201903-0671 2019 | The Israel Diamond Industry | Pink diamonds win big in 2018. | israelidiamond.co.il, Feb. 1, 1/4p. | Global | News item - diamond colour |
DS201905-1032 2014 | Gaillou, E., Rossman, G.R. | Color in natural diamonds .. The beauty of defects. Note date *** | Rocks & Minerals, 12p. | Global | diamond colour |
| Abstract: In its pure form, diamond is colorless. However, in nature (or even when made in laboratories), diamonds are never composed of 100 percent carbon atoms. Even colorless diamonds will contain some defects: missing carbon atoms or containing trace amounts of nitrogen or hydrogen, for example. When present in certain atomic arrangements and concentrations, most minor components cause absorption of specific wavelengths of light, giving rise to color. The color in diamond is not source specific, even if some mines are known to produce more of certain colors, such as blue diamonds from the Premiere mine in South Africa, or brown and pink diamonds from the Argyle mine in Australia. Virtually every single diamond mine could produce any kind of colored diamond. At auction, record prices for gems are currently held by pink and blue diamonds: for example, $2,155,332 per carat for a 24.78-carat Fancy vivid pink diamond (sold at Sotheby's in 2010) and $1.8 million per carat for a 5.3-carat Fancy deep blue diamond (sold at Bonhams in London in April 2013). |
DS201907-1551 2019 | Howell, D., Collins, A.T., Loudin, L.C., Diggle, P.L., D;Haenens-Johansson, U.F.S., Smit, K.V., Katrusha, A.N., Butler, J.E., Nestola, F. | Automated FTIR mapping of boron distribution in diamond. Type Ilb | Diamond and Related Materials, in press available 33p. | Global | DiaMap |
| Abstract: Type IIb diamonds are those that contain more boron than nitrogen. The presence of this uncompensated boron gives rise to absorption in the infrared part of the electromagnetic spectrum, extending into the visible region and often resulting in blue colouration. Here we report on the expansion of the DiaMap freeware (for the automated spectral deconvolution of Type I [nitrogen containing] diamonds) to work on Type IIb diamonds, returning concentrations from three boron-related absorption bands, and determining which band provides the most reliable value. The program uses the calibration coefficients of Collins (2010), which show good relative agreement between the three bands, but might require some further study to confirm their absolute accuracy to the uncompensated boron concentration. The methodology of DiaMap_IIb is applicable to all Type IIb diamonds, both natural and synthetic. Analysis of high-resolution Fourier-transform infrared (FTIR) maps of two high-pressure high-temperature (HPHT) synthetic diamonds using DiaMap_IIb, confirm the growth sector dependence of the boron incorporation. Partitioning of boron strongly favours the octahedral {111} sectors. |
DS201907-1575 2019 | Smith, E.M., Shirey, S.B., Richardson, S.H., Nestola, F., Bullocks, E.S., Wang, J., Wang, W. | Reply to: Evidence for two blue (type Ilb) diamond populations. ( Moore and Helmstaedt Nature Vol. 570, E26-27. | Nature, Vol. 570, E28-29. | Mantle | boron |
DM201908-1971 2019 | The West Australian | Pink diamonds' price perk. Argyle | thewestaustralian.com, July 2, 1p. | Australia | News item - pink diamonds |
DS202001-0018 2019 | Huang, W., Ni, P., Shui, T., Shi, G. | Hydrogen rich green diamond color treated by multi step processing. | Gems & Gemology, Vol. 55, 3, pp. 398-405. | Global | diamond color |
| Abstract: A cut diamond of intense yellowish green color has been characterized using microscopy and spectroscopic techniques. The diamond has been unambiguously identified as color-treated. The simultaneous presence of multiple centers related to irradiation and annealing—including H1a, H1b, NV0, NV-, H3, H4, GR1, and H2—was revealed. UV-Vis-NIR absorption spectroscopy showed that the diamond owes its color to the two major bands related to H3 and GR1. The combination of these spectroscopic features in one diamond has not been reported in the gemological literature, suggesting that this diamond was subjected to a complex treatment procedure that is not frequently applied. Taking into account the thermal stability of the defects involved and the defect transformations at high temperatures, two possible treatment procedures explaining the observed combination of spectroscopic features are proposed. |
DS202003-0348 2020 | Lee, C.W.Y., Cheng, J., Yium Y.C., Chan, K., Lau, D., Tang, W.C., Cheng, K.W,m Kong, T., Hui, T.K.C., Jelezko, F. | Correlation between EPR spectra and coloration of natural diamonds. | Diamond & Related Materials, Vol. 103, 13p. Pdf | Global | diamond colour |
| Abstract: White diamonds color grading is one of the basic diamond evaluations. The color value based on a scale that ranges from D to Z, with D being the more colorless and more valuable, among other qualifications. As the diamond grade moves on this scale, its color appears more yellow progressively. This yellowish color, present only in Type I diamonds, is mainly due to the nitrogen related defects such as N3 center and C-center. The current color grading system is based on a visual method, where gemologist compares the sample with a Master Color set. However, this method is very subjective. Several defects responsible for light absorption in diamond are carrying electron spin and appear in Electron Paramagnetic Resonance (EPR) spectrum. In this study, we developed a new EPR based technique for a quantitative measurement of N3 center and C-center in diamond through quantitative EPR spectroscopy. The correlation between EPR spectra and color grades of diamond was established. |
DS202003-0362 2020 | Sha, X., Yue, W., Zhang, H., Qin, W., She, D., Wang, C. | Thermal stability of polycrystalline diamond compact sintered with boron coated diamond particles. | Diamond & Related Materials, in press available, 34p. Pdf | Global | boron |
| Abstract: The polycrystalline diamond compact (PDC), which consists of a polycrystalline diamond layer on a tungsten carbide (WC)/cobalt (Co) substrate, is extensively utilized as drilling bits. However, the poor thermal stability due to the graphitization and oxygen susceptibility of diamond severely limits the application of PDCs to high-temperature drilling work. In this study, a new PDC with improved thermal stability is successfully synthesized with boron (B)-coated diamond particles, which forms a uniform boron carbide (B4C) barrier. The as-received B4C phase acts as a protective barrier, which enhances the initial graphitization and oxidizing temperatures to 800 °C and 780 °C, respectively, which are ~100 °C and ~30 °C higher than those (700 °C and 750 °C) of the PDC sintered with uncoated diamond particles. The B4C barrier protects diamond grains from direct contact with the Co phase, prohibiting the cobalt-catalytic graphitization. In addition, the oxidation of the B4C barrier occurs prior to that of the diamond grains, which inhibits the PDC from oxidation. |
DM202008-1491 2020 | Diamonds.net | NCDIA crates coloured diamond ambassador group. | diamonds.net, July 15, 1/4p. | Global | News item - NCDIA |
DM202012-2262 2020 | Australian Mining | Rio Tinto hosts second last Argyle diamonds tender. Argyle Eternity 2.24 carats fancy vivid purplish pink, 2.45 Argyle Ethereal, 1.84 ct Argyle Sakura, 0.43 Argyle Emrys, Argyle Skylar 0.33, Argyle Infinite 0.70 ct | Australianmining.com, Nov. 18, 1/3p. | Australia | News item - pink diamonds |
DS202102-0196 2020 | Hainschwang, T. | Wrestling with radiation ( diamonds) | Gems & Jewellery, Vol. 29, 4, pp. 28-41. | Global | diamond colour |
DM202103-0452 2021 | Diamonds.net | Fancy-color price index sees slight decline. | Diamonds.net, Feb. 15, 1/4p. | Global | News item - colour |
DS202103-0377 2020 | Eaton-Magana, S., Ardon, T., Breeding, C.M., Shigley, J.E. | Natural color D-to-Z diamonds: a crystal clear perspective. | Gems & Gemology, Vol. 56, 3, pp. 318-335. pdf | Global | diamond - colour |
| Abstract:
Colorless to light yellow or brown diamonds with a “D-to-Z” color grade make up the overwhelming majority of the world’s gem diamond trade. Besides clarity features (such as inclusions) and fluorescence observations, however, comparatively little has been explored and published regarding the distinguishing characteristics of these diamonds. The vast majority are type Ia, with infrared spectra showing very high concentrations of nitrogen aggregates. This population of diamonds could not have been subjected to HPHT decolorizing treatment or been laboratory grown, and thus they have been spectroscopically scrutinized in much less detail than the far more rare natural diamonds of types IIa, IIb, and IaB, which need to be investigated as potentially color-treated or synthetic. This study examines a large sample set comprising the full complement of D-to-Z diamonds submitted to GIA laboratories during a significant portion of 2017. The data were evaluated on the basis of diamond type properties, as well as distribution among various grading quality factors, to provide an unprecedented glimpse into the role of these diamond types and differences in their geologic conditions of formation. |
DM202103-0509 2021 | Rough-polished | FCRF report: minor decrease in fancy color diamond prices in 2020. | Rough-polished.com, Feb. 19, 1/4p. | Global | News item - colour |
DS202104-0573 2021 | Eaton-Magana, S., Ardon, T., Breeding, C., Shigley, J. | D-Z Diamonds ( Ardon presents the information from the article in Gems & Gemology **** see ref under Ahline same one……. | gia.org and knowledge session utube, March | Global | Diamond colour |
| Abstract: Did you know that certain diamonds can temporarily change color when exposed to heat, ultraviolet light, or even when kept in the dark? Some natural greenish diamonds are known as “chameleon” diamonds due to this property. Other natural pink diamonds and some color-treated and laboratory-grown diamonds can also change color in unexpected ways. Before this phenomenon was known, there were stories of customers returning diamonds they purchased because the diamonds turned out to be the “wrong” color! What exactly causes these interesting diamonds to shift their hues? Find out as GIA senior manager of diamond research Dr. Ulrika D'Haenens-Johansson and senior research scientist Dr. Mike Breeding dive into the mystery of these ultra-cool gems. |
DS202105-0778 2021 | Muruganathan, M., Mizuta, H. | Boron vacancy color center in diamond: An initio study. | Diamond & Related Materials, Vol. 114, 108341 6p. Pdf | Global | diamond colours |
| Abstract: The color centers in diamond are crucial for emerging single-photon sources, quantum technologies, and biological sensors. Even though boron is commonly used as a dopant for diamond, its functionality as a vacancy color center depends on the capability to excite electrons optically between the well-defined gap states. Here we show by using density functional theory calculations that the negatively charged boron-vacancy (BV?1) center in diamond possesses such well-isolated gap states and enables the spin-conserved triplet excitation. Formation energy of different charge states of boron vacancy center is calculated by including the corrections of electrostatic interactions between the periodic images of the charged defects and the defect-induced bands shift. Wavefunctions of diamond BV?1 center defect states are elucidated and its zero phonon line is calculated as 3.22 eV. These characteristics manifest that the BV?1 center can be harnessed as an alternative promising color center for diamonds. |
DS202105-0786 2021 | Razgulov, A.A., Lyanpin, S.G., Novikov, A.P., Ekimov, E.A. | Low-temperature photoluminescence study of SnV centers in HPHT diamond. | Diamond & Related Materials, Vol. 116, 108379 9p. Pdf | Global | diamond colours |
| Abstract: Here we report on the study of temperature shift and broadening of the zero phonon line (ZPL) of SnV center in HPHT microcrystalline diamond in the temperature range of 80-300 K. To separate contributions of lattice thermal expansion and electron-phonon coupling, the study of the pressure effect on the ZPL was conducted. A strong nonlinearity observed in the electron-phonon part of the ZPL temperature shift appeared to be in good agreement with well-known polynomial law ?E(T) = cT^2-dT^4 and, therefore, can be related to the effect of the strong softening of elastic springs. |
DM202106-1042 2021 | Rough-polished | FCRF: fancy color diamond prices increase in Q1 2021. | roughpolished.com, May 14, 1/4p. | Global | News item - colour diamonds |
DM202108-1352 2021 | Diamonds.net | The enduring appeal of pink gemstones: from rosy-hued diamonds to sapphires. | The National Lifestyle, July 30, 6p. | Global | News item - pink diamonds |
DS202108-1280 2021 | Eaton-Magana, S., Johnson, P., Barrie, E., Harinova, M. | Bicolor rough diamond crystals. ( pink) | Gems & Gemology , Vol. 57, 1, pp. 53-55. | Australia | diamond colour |
DM202111-1892 2021 | The West Australian | Rio Tinto's Argyle diamond mine's closure fuelling bull run for rare pinks. | thewestaustralian.com, Oct. 27, 1/2p. | Australia | News item - pink diamonds |
DM202111-1893 2021 | UKNewstoday | Third kind of colour-changing diamond ( only changes if chilled to -320 deg F ( temperature of liquid nitrogen) | UKNewsToday.com, Oct. 7, 2p. | Global | News item - chameleon |
DM202112-2014 2021 | Idex Online | Christie's to sell Blue diamond at online auction. $ 675,000 high estimte. | idexonline.com, Nov. 17, 1/4p. | Europe, United Kingdom | News item - Blue diamond |
DM202112-2049 2021 | Rough-polished | FCRF: Fancy coloured diamonds price increases by 0.7% in Q3. | rough-polished.com, Nov. 9, 1/4p. | Global | News item - FRCF |
DM202112-2081 2021 | The Gothamist | A new exhibit at the American Museum of Natural History showcases a rare 20 carat blue diamond from Botswana. Okavango | thegothamist.com, Nov. 12, 1/4p. | Africa, Botswana | News item - Okavango Blue |