Abstract In the present work, a lamella from an Au—Ag aggregate found in Ni-laterites has been examined using Transmission Electron Microscope to produce a series of Precision Electron Diffraction (PED) patterns. The analysis of the structural data obtained, coupled with Energy Dispersive X-ray microanalysis, made it possible to determine the orientation of twinned native gold growing on the Au—Ag aggregate. The native Au crystal domains are found to have grown at the outermost part of the aggregate whereas the inner core of the aggregate is an Au—Ag alloy (∼4 wt% Ag). The submicron structural study of the natural occurring Au aggregate points to the mobilization and precipitation of gold in laterites and provides insights on Au aggregates development at supergene conditions. This manuscript demonstrates the great potential of electron crystallographic analysis, and in particular, PED to study submicron structural features of micron sized mineral aggregates by using the example of a gold grain found in a Ni-laterite deposits.

中文翻译：

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通过旋进电子衍射 (PED) 阐明了天然存在的 Au-Ag 聚集体上的 Au 晶体生长。

摘要在目前的工作中，使用透射电子显微镜检查了在镍红土中发现的 Au-Ag 聚集体的薄片，以产生一系列精密电子衍射 (PED) 图案。对获得的结构数据进行分析，再加上能量色散 X 射线微量分析，可以确定在 Au-Ag 聚集体上生长的孪晶原生金的方向。发现天然 Au 晶体域在聚集体的最外层生长，而聚集体的内核是 Au-Ag 合金（~4 wt% Ag）。天然存在的 Au 聚集体的亚微米结构研究指出了红土中金的移动和沉淀，并提供了对表生条件下 Au 聚集体发展的见解。