Search Results - "Benjamin Rondeau"

The origin of color in natural C center bearing diamonds by Hainschwang, Thomas, Fritsch, Emmanuel, Notari, Franck, Rondeau, Benjamin, Katrusha, Andrey

“…The properties of 152 natural diamonds with C centers – detectable by the absorptions at about 1344 and/or 2688cm−1 in the infrared spectra – were analyzed in…”
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Cracking of Gem Opals by Boris Chauviré, Valentin Mollé, Florine Guichard, Benjamin Rondeau, Paul Stephen Thomas, Emmanuel Fritsch

“…The value of gem opals is compromised by their potential susceptibility to “crazing”, a phenomenon observed either in the form of whitening or cracking. To…”
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Metamorphic and Metasomatic Kyanite-Bearing Mineral Assemblages of Thassos Island (Rhodope, Greece) by Alexandre Tarantola, Panagiotis Voudouris, Aurélien Eglinger, Christophe Scheffer, Kimberly Trebus, Marie Bitte, Benjamin Rondeau, Constantinos Mavrogonatos, Ian Graham, Marius Etienne, Chantal Peiffert

“…The Trikorfo area (Thassos Island, Rhodope massif, Northern Greece) represents a unique mineralogical locality with Mn-rich minerals including kyanite,…”
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New columnar texture of carbonado: Cathodoluminescence study by Rondeau, Benjamin, Sautter, Violaine, Barjon, Julien

“…We investigated a very unusual sample of carbonado by optical and electron microscopy, and cathodoluminescence imaging and spectroscopy. We observed two…”
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Three historical ‘asteriated’ hydrogen-rich diamonds: growth history and sector-dependent impurity incorporation by Rondeau, Benjamin, Fritsch, Emmanuel, Guiraud, Michel, Chalain, Jean-Pierre, Notari, Franck

“…Three historical ‘asteriated’ diamond slices present mixed-habit growth with contemporaneous lobe-shaped cuboid sectors and octahedral sectors. The lobe shape…”
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Oxygen Isotopes and Emerald Trade Routes since Antiquity by Giuliani, Gaston, Chaussidon, Marc, Schubnel, Henri-Jean, Piat, Daniel H., Rollion-Bard, Claire, France-Lanord, Christian, Giard, Didier, de Narvaez, Daniel, Rondeau, Benjamin

“…Oxygen isotopic compositions of historical emerald artifacts from the Gallo-Roman period to the 18th century indicate that during historical times, artisans…”
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Near-infrared signature of hydrothermal opal: a case study of Icelandic silica sinters by Pineau, Maxime, Chauviré, Boris, Rondeau, Benjamin

“…Silica minerals constitute a main target to assess the origin of life or the possibility of its emergence. On Earth, ancient hydrothermal silica deposits have…”
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Toward the geological significance of hydrated silica detected by near infrared spectroscopy on Mars based on terrestrial reference samples by Pineau, M., Le Deit, L., Chauviré, B., Carter, J., Rondeau, B., Mangold, N.

“…Hydrated silica detected on the martian surface, from both orbital and in-situ data, is an indicator of past aqueous conditions. On Earth, several near…”
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The precious opal deposit at Wegel Tena, Ethiopia; formation via successive pedogenesis events by Chauviré, Boris, Rondeau, Benjamin, Mazzero, Francesco, Ayalew, Dereje

“…Since its discovery in 2008, the opal deposit in the Wegel Tena area of Ethiopia, located within an Oligocene ignimbritic trap, has become a major provider of…”
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Whitening of fire opal: Transformation of silica in soils by Gouzy, Simon, Rondeau, Benjamin, Gaudin, Pierre, Louarn, Guy, La, Carole, Lebeau, Thierry, Vinogradoff, Vassilissa, Clodoré, Laura, Chamard-Bois, Sarah

“…Of all the world's gem opal deposits, Ethiopian's ones stand out for their quantitative production of white opals and orange fire opals. They also provide a…”
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Pedogenic origin of precious opals from Wegel Tena (Ethiopia): Evidence from trace elements and oxygen isotopes by Chauviré, Boris, Rondeau, Benjamin, Alexandre, Anne, Chamard-Bois, Sarah, La, Carole, Mazzero, Francesco

“…The trace element and oxygen isotope composition of Wegel Tena (Ethiopia) gem opals was measured to provide evidence of the conditions of their genesis…”
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Hydrothermal genesis and growth of the banded agates from the Allumiere-Tolfa volcanic district (Latium, Italy) by Conte, Alessandra, Della Ventura, Giancarlo, Rondeau, Benjamin, Romani, Martina, Cestelli Guidi, Mariangela, La, Carole, Napoleoni, Camilla, Lucci, Federico

“…In this work, we studied the hydrothermal agates from the Neogene–Quaternary volcanic district of Allumiere-Tolfa, north-west of Rome (Latium, Italy) using a…”
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Why are some crystals gem quality? Crystal growth considerations on the "gem factor" by Fritsch, Emmanuel, Rondeau, Benjamin, Devouard, Bertrand, Pinsault, Lauriane, Latouche, Camille

“…The purpose of this work is to investigate the crystal growth parameters necessary or sufficient to obtain a crystal specifically of gem quality. We assume…”
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A new defect center in type Ib diamond inducing one phonon infrared absorption: The Y center by Hainschwang, Thomas, Fritsch, Emmanuel, Notari, Franck, Rondeau, Benjamin

“…The infrared spectra of 68 natural and synthetic diamonds with detectable C centers at about 1130 cm − 1 and 1344 cm − 1 were recorded. After correction and…”
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Reverse dichromatism in gem andalusite related to total pleochroism of the Fe2+-Ti4+ IVCT by Rondeau, Benjamin, Chamard-Bois, Sarah, Fritsch, Emmanuel, Notari, Franck, Chauviré, Boris

“…We document a dichromatism effect in gem andalusite that shifts from light brownish pink at low thickness to medium green at high thickness. This is roughly…”
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Reverse dichromatism in gem andalusite related to total pleochroism of the Fe 2+ -Ti 4+ IVCT by Rondeau, Benjamin, Chamard-Bois, Sarah, Fritsch, Emmanuel, Notari, Franck, Chauviré, Boris

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Arthropod entombment in weathering-formed opal: new horizons for recording life in rocks by Chauviré, Boris, Houadria, Mickal, Donini, Aline, Berger, Brian T., Rondeau, Benjamin, Kritsky, Gene, Lhuissier, Pierre

“…Animal fossils preserved in various geological materials, such as limestone, claystone, or amber, provide detailed information on extinct species that is…”
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A contribution to the understanding of pink color in diamond: The unique, historical «Grand Condé by Fritsch, Emmanuel, Rondeau, Benjamin, Hainschwang, Thomas, Quellier, Marie-Hélène

“…We recorded properties of a historical 9.01 ct pink diamond, the Grand Condé. It is a type IIa diamond that shows very weak absorptions at 860, 960, 1050, 1115…”
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Voluminous Silica Precipitated from Martian Waters during Late-stage Aqueous Alteration by Pan, Lu, Carter, John, Quantin-Nataf, Cathy, Pineau, Maxime, Chauviré, Boris, Mangold, Nicolas, Le Deit, Laetitia, Rondeau, Benjamin, Chevrier, Vincent

“…Mars’ transition from an early “warm and wet” to a “cold and dry” environment left fingerprints on the geological record of fluvial activity on Mars. The…”
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Investigation of hidden periodic structures on SEM images of opal-like materials using FFT and IFFT by Stephant, Nicolas, Rondeau, Benjamin, Gauthier, Jean-Pierre, Cody, Jason A., Fritsch, Emmanuel

“…Summary We have developed a method to use fast Fourier transformation (FFT) and inverse fast Fourier transformation (IFFT) to investigate hidden periodic…”
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