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在低饱和度、碱性、气成—热液条件下形成的四川平武绿柱石宝石晶体 ,具有特征的扁平板状几何外形。在绿柱石晶体的 { 0 0 0 1}、{ 10 10 }、{ 112 1}面上 ,普遍发育螺旋位错、束合螺旋位错、层错及接触双晶 ,它们共同构成了绿柱石晶体生长的主要台阶源。微分干涉显微镜、扫描电镜和透射电镜研究结果证实 ,由填隙变形、位错滑移和水解弱化等综合作用 ,直接导致绿柱石硅氧四面体六方环结构和铍氧四面体结构的局部畸变 ,并相应引起多面体体积、化学键力、键合能及晶面的法向生长速率发生变化 ,从而决定了该区绿柱石晶体生长的形态。由绿柱石晶体中的线缺陷 (螺旋位错 )、面缺陷 (层错、双晶 )及点缺陷 (空位、包裹体 )的协同作用 ,是导致四川平武扁平板状绿柱石晶体形成的主要原因
The low-saturation, alkaline, gas-hydrothermal conditions formed in Sichuan Pingwu Beryl gemstone crystals, with the characteristics of the flat plate-shaped geometry. On the {0 0 0 1}, {10 10}, {112 1} planes of beryl crystals, helical dislocations, coiled screw dislocations, stacking faults and contact twins are commonly developed and together they form beryl crystals The main source of growth. The results of differential interference microscopy, scanning electron microscopy and transmission electron microscopy confirm that the local distortion of the hexagonal ring structure and the beryllium-oxygen tetrahedron structure of the beryl are directly caused by the combined effect of the interstitial deformation, dislocation slip and hydrolytic weakening, And the corresponding volume, chemical bond force, bonding energy and the normal growth rate of the crystal plane change, which determines the morphology of the beryl crystal growth in this area. The synergistic effect of the line defects (helical dislocations), the plane defects (faults, twin crystals) and the point defects (vacancies and inclusions) in the beryl crystals is the main cause of the formation of flat beryl crystals in Pingwu flat, Sichuan the reason