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DOI

  • I. V. Klepikov
  • Евгений Васильев
  • Людмила Лукьянова

Abstract: Three hundred thirty-six diamonds from deposits of the Rassolninskaya depression and 144 crystals from recent alluvial placers of the Krasnovishersky district were studied by IR absorption and photoluminescence spectroscopy. It is shown that crystals from the Rassolninskaya depression have a close-to-normal distribution for the nitrogen concentration. The average nitrogen content is 725 ppm, and no nitrogen-free crystals were detected. A sampling from recent alluvial placers contains 25% crystals with a nitrogen concentration smaller than 150 ppm; 3% of them are nitrogen-free. Among crystals from the Rassolninskaya depression, 12% are octahedral, 80% rhombododecahedral, and only one crystal has relicts of cubic faces. The collection from recent placers contains 3% cubic crystals, 10% individuals with relicts of cubic faces, 16% octahedroids, and 66% dodecahedra. Alluvial diamonds are often encountered with crescent-shaped cracks; however, they were observed only on a single crystal from the Rassolninskaya depression. It has been revealed that among alluvial placer diamonds, up to 95% of crystals contain nitrogen in the form of B1 defects. Thus, first, in morphological and structural-mineralogical features, diamonds from the Rassolninskaya depression differ from crystals of the nearest recent alluvial placers; second, they may belong to primary deposits based on the set of their characteristics.

Original languageEnglish
Pages (from-to)598-605
Number of pages8
JournalGeology of Ore Deposits
Volume61
Issue number7
DOIs
StatePublished - 1 Dec 2019

    Research areas

  • diamonds, FTIR, morphology, photoluminescence, placer, Rassolninskaya depression, Urals

    Scopus subject areas

  • Geology
  • Geochemistry and Petrology
  • Economic Geology

ID: 86253817