Superficial nanotextures of placer gold

Abstract

The methods of high-resolution electron microscopy were applied to study nanotex-tures on the surface of placer gold grains (the Urals, Siberia, Altai in Russia, Yukon Territory in Canada, etc.). Among superficial nanotextures, the cracks, furrows, pores, films, inclusions, monolayers, complicated aggregates with gold of relevant size were described. It is supposed that the nanotextures on gold surface partly depend on internal structure of metal and afterwards reflect diverse influences of supergenic factors. Some of them (nanocracks, nanopores) are connected with defects of crystal lattice. A presence of nanolayers reflects instability of gold grain growth, as well as nanoinclu-sions point to its genesis. The secondary products of weathered rocks such as individual nanoparticles, their aggregates, nanofilms of Fe, Al, Si, and other compounds, coverings, and growths of "new" gold are discovered on a gold surface. There are the assumptions that gold surface nanotextures may promote remarkable changes in chemical, physical and mechanical properties of the metal, especially in the flotation activity, settling velocity and absorption capacity.