{"title":"Morphological Features and Genesis of the Interpenetration Twins of Cubic Diamond Crystals","authors":"A. D. Pavlushin","doi":"10.1134/S0016702924700897","DOIUrl":null,"url":null,"abstract":"<p>The paper presents analysis of the crystal morphology of two similarly shaped interpenetration twins of cubic crystals: the Chinese Lantern diamond (Arkhangelsk diamond mining province, provided for this study by courtesy of the ALROSA company) and a diamond crystal from Brazil, which has been studied in much detail by A.E. Fersman. Comparison of data on these diamonds, which were obtained using original methodological techniques for interpreting morphological indications of crystal growth and dissolution, revealed a number of crystal morphological features of crystals characteristic of regular accretions of this type. In addition to tetragonal pits characteristic of the cuboids, ribbon-shaped, jagged, and drop-shaped relief features typical of surface dissolution, a new type of symmetrical sawtooth microrelief associated with etching of octahedral layers of cuboid growth was discovered on the diamond from the Arkhangelsk province. In accordance with the height and direction of the steps of the relief pattern, the development sequence of the aforementioned types of microrelief is determined according to the increase in the depth of dissolution and the degree of change in the curvature of the surface of the tetrahexahedron on twin cuboids. The genesis of the characteristic equatorial sharp ridge of octahedron faces encircling the twinning plane was revealed. It is demonstrated to has been formed in relation to an early stage of the systematic coalescence of fibrous diamond cuboids and to be a determining condition of its development, first as a interpenetration twin of flat-faced octahedral crystals. Crystal morphological similarities between indications of dissolution on curved tetrahexahedra from kimberlites of the Arkhangelsk pipes and placer sources in Brazil and the north of the Yakutian diamond-bearing province is discussed.</p>","PeriodicalId":12781,"journal":{"name":"Geochemistry International","volume":"63 2","pages":"172 - 182"},"PeriodicalIF":0.7000,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Geochemistry International","FirstCategoryId":"89","ListUrlMain":"https://link.springer.com/article/10.1134/S0016702924700897","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
The paper presents analysis of the crystal morphology of two similarly shaped interpenetration twins of cubic crystals: the Chinese Lantern diamond (Arkhangelsk diamond mining province, provided for this study by courtesy of the ALROSA company) and a diamond crystal from Brazil, which has been studied in much detail by A.E. Fersman. Comparison of data on these diamonds, which were obtained using original methodological techniques for interpreting morphological indications of crystal growth and dissolution, revealed a number of crystal morphological features of crystals characteristic of regular accretions of this type. In addition to tetragonal pits characteristic of the cuboids, ribbon-shaped, jagged, and drop-shaped relief features typical of surface dissolution, a new type of symmetrical sawtooth microrelief associated with etching of octahedral layers of cuboid growth was discovered on the diamond from the Arkhangelsk province. In accordance with the height and direction of the steps of the relief pattern, the development sequence of the aforementioned types of microrelief is determined according to the increase in the depth of dissolution and the degree of change in the curvature of the surface of the tetrahexahedron on twin cuboids. The genesis of the characteristic equatorial sharp ridge of octahedron faces encircling the twinning plane was revealed. It is demonstrated to has been formed in relation to an early stage of the systematic coalescence of fibrous diamond cuboids and to be a determining condition of its development, first as a interpenetration twin of flat-faced octahedral crystals. Crystal morphological similarities between indications of dissolution on curved tetrahexahedra from kimberlites of the Arkhangelsk pipes and placer sources in Brazil and the north of the Yakutian diamond-bearing province is discussed.
期刊介绍:
Geochemistry International is a peer reviewed journal that publishes articles on cosmochemistry; geochemistry of magmatic, metamorphic, hydrothermal, and sedimentary processes; isotope geochemistry; organic geochemistry; applied geochemistry; and chemistry of the environment. Geochemistry International provides readers with a unique opportunity to refine their understanding of the geology of the vast territory of the Eurasian continent. The journal welcomes manuscripts from all countries in the English or Russian language.