HPHT treatment of CO2 containing and CO2-related brown diamonds

Hainschwang, Thomas; Notari, Franck; Fritsch, Emmanuel; Massi, L.; Rondeau, B.; Breeding, Christopher M.; Vollstaedt, Heiner

doi:10.1016/j.diamond.2008.01.022

Cited by 27 publications

(41 citation statements)

References 14 publications

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“…In natural diamonds exhibiting pronounced Y-center, the absorption 480 nm band and the luminescence 680 nm band can reveal high intensity after irradiation and high temperature HPHT annealing (Fig. The 680 nm band stands HPHT treatment at 2,100°C (Hainschwang et al 2008). This behavior is in contrast with that observed in plastically deformed brown diamonds (Hainschwang et al 2008).…”

Section: Nm (26 Ev) Bandmentioning

confidence: 87%

“…However, the strain alone does not result in brown color. b A natural diamond exhibiting brown coloration due to high content of CO 2 molecules (Hainschwang et al 2008) (with permission of the Diamond and Related Materials journal) coloration in the slip planes is a slow kinetic process occurring after the internal strain has been induced. It might be that the concentration of the defects responsible for the brown (Kitawaki 2007).…”

Section: Brownmentioning

confidence: 99%

“…The defects contributing to brown color of irregular brown diamonds have been identified as C defects in type Ib diamond, micro-inclusions of non-diamond phases, imbedded CO 2 molecules, hydrogen-related defects, some unknown intrinsic defects in type IIa and IaB diamonds (Ewels et al 2001;Hainschwang et al 2008; Barnes et al 2006). These diamonds can be termed as irregular brown diamonds.…”

Section: Brownmentioning

confidence: 99%

“…Brown color of irregular diamonds (CO 2 and pseudo-CO 2 diamonds) is not affected noticeably by HPHT treatment and many irregular brown diamonds do not change their color at all (Hainschwang et al 2008Reinitz et al 2000;Chapman 2010). Brown color of irregular diamonds (CO 2 and pseudo-CO 2 diamonds) is not affected noticeably by HPHT treatment and many irregular brown diamonds do not change their color at all (Hainschwang et al 2008Reinitz et al 2000;Chapman 2010).…”

Section: Irregular Brown Diamondsmentioning

confidence: 99%

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HPHT-Treated Diamonds

Dobrinets

Vins²,

Зайцев

2013

Springer Series in Materials Science

107

135

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Section: Nm (26 Ev) Bandmentioning

confidence: 87%

Section: Brownmentioning

confidence: 99%

Section: Brownmentioning

confidence: 99%

Section: Irregular Brown Diamondsmentioning

confidence: 99%

See 2 more Smart Citations

HPHT-Treated Diamonds

Dobrinets

Vins²,

Зайцев

2013

Springer Series in Materials Science

107

135

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“…Computer modeling of large clusters of vacancies has yielded results that are compatible with such observations (Fujita et al 2008). Less commonly, brownish colors can be caused by hydrogen or isolated nitrogen atoms (Fritsch 1998, Lindblom et al 2005, H4 centres (Collins et al 2000), or possibly CO 2 (Hainschwang et al 2008). This paper is concerned only with the brown color due to plastic deformation and vacancy clusters.…”

Section: Introductionmentioning

confidence: 98%

Survival of the Brown Color in Diamond During Storage in the Subcontinental Lithospheric Mantle

Smith

Helmstaedt

Flemming

2010

The Canadian Mineralogist

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The common brown color in natural diamond is likely caused by vacancy clusters, produced by plastic deformation of the crystal structure. A brief treatment in a high-pressure -high-temperature (HPHT) vessel at 1800-2700°C can remove this color. As there has been speculation that a similar removal of color should occur continuously at depth in the subcontinental lithospheric mantle (SCLM), the effect of temperature on the time required to eliminate the brown color in diamond has been calculated from published data. A critical component of this calculation is the activation energy for the breakup of vacancy clusters. The time necessary to remove the brown color in the SCLM is significant on a geological time-scale. Crystals of brown diamond stored at or below about 1000°C should maintain their color for 10 8 years or more. In spite of some uncertainty in extrapolating the HPHT data to natural conditions in the SCLM, it appears that higher temperatures toward the base of the lithosphere could lead to reduction or elimination of the brown color within thousands of years. Plastic deformation needed to produce the brown color causes lattice distortion and strain-related mosaic spread, which is discernible by X-ray diffraction. The degree of mosaic spread was gauged in 18 untreated crystals of natural diamond by estimating -dimension peak-widths from micro-X-ray diffraction (mXRD). For these samples, there is a correlation between peak width and depth of brown color. None of the colorless crystals of diamond examined have large peak-widths, as should be expected for a crystal of diamond that has been deformed and turned brown, but later lost its brown color. The removal of the brown color thus does not seem to be a common natural occurrence. We thus conclude that survival of the brown color in the lithospheric mantle does not require the color to be formed late in the storage history, nor does it require metastable storage of diamond in the stability field of graphite.Keywords: brown diamond, high-pressure -high-temperature treatment, vacancy cluster, mosaic spread. SoMMaIrELa couleur brune habituelle du diamant naturel serait attribuable à des agrégats de lacunes qui seraient dues à une déformation plastique de la structure cristalline. Un bref traitement à haute pression et haute température à 1800-2700°C peut éliminer cette couleur. Afin d'évaluer les mérites de l'hypothèse voulant qu'une élimination de la couleur pourrait avoir lieu de façon continue dans le manteau lithosphérique subcontinental en profondeur, nous avons calculé l'effet de la température sur l'intervalle de temps requis pour éliminer la couleur brune à partir de données dans la littérature. Un facteur d'importance capitale dans ce calcul serait l'énergie d'activation de la dispersion de ces nanoagrégats de lacunes. Le temps requis pour éliminer la couleur brune dans le manteau lithosphérique subcontinental est appréciable sur une échelle de temps géologique. Les cristaux bruns tenus à environ 1000°C ou moins devraient maintenir leur couleur pour 10...

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High‐Pressure Carbonaceous Phases as Minerals

Tschauner

2020

Geophysical Monograph Series

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High-pressure carbonaceous minerals establish a link between one of the most abundant chemical elements and processes that occur at high pressures, either in the interior of the Earth or during shock-metamorphosis in space or on Earth. Diamonds from the Earth's mantle carry inclusions of carbides, carbonates, methane, and carbon-dioxide. These inclusions elucidate diamond formation and the carbon recycling in the mantle. This chapter focuses on these inclusion minerals themselves, the means of detection, and the reconstruction of pressure-temperature conditions of their formation in the mantle.

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HPHT treatment of CO2 containing and CO2-related brown diamonds

Cited by 27 publications

References 14 publications

HPHT-Treated Diamonds

HPHT-Treated Diamonds

Survival of the Brown Color in Diamond During Storage in the Subcontinental Lithospheric Mantle

High‐Pressure Carbonaceous Phases as Minerals

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