Au films deposited under ultra-high vacuum conditions on air-cleaved mica substrates were exposed in situ to Hg vapor (residual gas pressure similar to 1 X 10(-7) Pa, with Hg vapor pressure of 0.24 Pa). This led to transformation of continuous gold film into isolated amalgam islands of nanometer scale. The changes of Au thin film surface topography caused by amalgamation carried out within similar to 40 h were studied by the atomic force microscopy method, while the phase transition in the bulk of Hg-dosed Au films was monitored by means of X-ray diffraction. The island's morphology varies from irregular, ramified structures on terraces to compact shapes along the steps on the mica substrate. After thermal decomposition of the amalgam, thin gold films consisting of isolated Au nanostructures on mica can be obtained. (c) 2004 Elsevier B.V. All rights reserved.