Silver nanoparticles have been formed on the surface of lead crystal glass by means of (i) ion-exchange of alkaline ions from the glass by Ag+ ions from a molten salts bath, and (ii) silica based sol-gel coatings containing silver. All experimental variables concerning both ion-exchange process and sol-gel coatings application were combined and studied as main parameters governing the reduction of Ag+ ions to Ag-0 atoms and further aggregation to form nanosized colloids. The content of thermoreducing agents (arsenic or antimony oxides) in the lead crystal glass was essential to favour the reduction of silver ions to form nanoparticles. Optimal experimental conditions to be used for the obtaining of surface silver nanoparticles were determined. TEM was used as the principal characterisation technique for direct observation of the nanoparticles generated. The size of silver colloids varied in the 20-300 nm range for ion-exchanged samples and in the 10-80 nm range for sol-gel coated samples. (c) 2006 Elsevier B.V. All rights reserved.