On the internal structure of natural diamonds of cubic habit

Moore, Moreton; Lang, A. R.

doi:10.1080/14786437208220345

Cited by 78 publications

(35 citation statements)

References 7 publications

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“…Unlike crystal volumes with abundant inclusions, only the wavy extinction or the specific tatami-like patterns are visible in the crossed polarizers ( Figure 3). Such patterns are usually explained by a plastic deformation and fibrous internal structures specific to diamonds with cubic habits [22,23]. In the volume of crystals with abundant inclusions, strong interference is fixed which indicates a high deformation of the crystal structure.…”

Section: Optical Microscopymentioning

confidence: 99%

Specific Internal Structure of Diamonds from Zarnitsa Kimberlite Pipe

et al. 2017

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Abstract:The Zarnitsa kimberlite pipe is one of the largest pipes of the Yakutian diamondiferous province. Currently, some limited published data exists on the diamonds from this deposit. Among the diamond population of this pipe there is a specific series of dark gray to black diamonds with transition morphologies between octahedron and rounded rhombic dodecahedron. These diamonds have specific zonal and sectorial mosaic-block internal structures. The inner parts of these crystals have polycrystalline structure with significant misorientations between sub-individuals. The high consistency of the mechanical admixtures (inclusions) in the diamonds cores can cause a high grid stress of the crystal structure and promote the block (polycrystalline) structure of the core components. These diamond crystals have subsequently been formed due to crystallization of bigger sub-individuals on the polycrystalline cores according to the geometric selection law.

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Section: Optical Microscopymentioning

confidence: 99%

Specific Internal Structure of Diamonds from Zarnitsa Kimberlite Pipe

et al. 2017

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“…Formation of cuboid diamonds was suggested to proceed through different growth modes: (i) a "fibrous" (columnar) growth in the <111> direction, and (ii) "cuboids" growth of the crystals which do not show a fibrous internal structure [35]. In both cases, the cuboid habit of diamonds may be a primary feature, reflecting rough growth under high degrees of carbon supersaturation which operates as the driving force for diamond growth [36].…”

Section: Discussionmentioning

confidence: 99%

The Carbon and Nitrogen Isotope Characteristics of Type Ib-IaA Cuboid Diamonds from Alluvial Placers in the Northeastern Siberian Platform

Zedgenizov¹,

Reutsky²,

Wiedenbeck³

2017

Preprint

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Cuboid diamonds are particularly common in the placers of the northeastern Siberian platform but their origin remains unclear. These crystals usually range in color from dark yellow to orange and more interestingly, are characterized by unusual low aggregated nitrogen impurities (non-aggregated C-center) suggesting a short residence time and/or low temperatures at which they have been stored in the mantle. In order to track possible isotopic signature that could help deciphering cuboid diamond's crystallization processes, δ 13 C values, δ 15 N values and nitrogen contents have been determined in-situ in three samples using secondary ion mass spectrometry (SIMS), whereas nitrogen aggregation state have been determined by FTIR spectroscopy. The samples fall out the δ 13 C vs. δ 15 N field of canonical mantle composition. Different scale of carbon and nitrogen fractionation may produce the observed variations. Alternatively, mixing of mantle and crustal material would obscure initial co-variations of δ 13 C values with δ 15 N or nitrogen content.

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“…The straining of the crystal structure may result from (1) dislocations; (2) lattice parameter deviations (caused by lattice impurities); (3) physical impurities (mineral and fluid inclusions; (4) cracks; and (5) plastic deformation [36]. The fibrous internal structure of diamonds with cubic habits, which consist of sub-parallel fibres diverging in lines from a common centre (crystals core), has been previously recognized by X-ray topography [31,38]. The misorientations between subindividuals (fibres) in studied diamonds produce a deformation of crystals, which results in the patterns of anomalous birefringence ( Figure 5).…”

Section: Optical Microscopymentioning

confidence: 99%

The Internal Structure of Yellow Cuboid Diamonds from Alluvial Placers of the Northeastern Siberian Platform

et al. 2017

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Yellow cuboid diamonds are commonly found in diamondiferous alluvial placers of the Northeastern Siberian platform. The internal structure of these diamonds have been studied by optical microscopy, X-Ray topography (XRT) and electron backscatter diffraction (EBSD) techniques. Most of these crystals have typical resorption features and do not preserve primary growth morphology. The resorption leads to an evolution from an originally cubic shape to a rounded tetrahexahedroid. Specific fibrous or columnar internal structure of yellow cuboid diamonds has been revealed. Most of them are strongly deformed. Misorientations of the crystal lattice, found in the samples, may be caused by strains from their fibrous growth or/and post-growth plastic deformation.

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On the internal structure of natural diamonds of cubic habit

Cited by 78 publications

References 7 publications

Specific Internal Structure of Diamonds from Zarnitsa Kimberlite Pipe

Specific Internal Structure of Diamonds from Zarnitsa Kimberlite Pipe

The Carbon and Nitrogen Isotope Characteristics of Type Ib-IaA Cuboid Diamonds from Alluvial Placers in the Northeastern Siberian Platform

The Internal Structure of Yellow Cuboid Diamonds from Alluvial Placers of the Northeastern Siberian Platform

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