Silver is quite a special element. It has the highest thermal and electrical conductivity of all metals. As a noble metal, it is very corrosion-resistant. Still, it is more reactive than gold or platinum.
Reactivity and also conductivity involve surface effects. These are especially interesting on the nano-scale when dimensions of the silver become extremely small and the surface-to-volume ratio increases strongly. The resulting efects and applications are manifold and have filled scientific BOOKS.
nano-silver absorbs light at a characteristic wavelength, which leads to a yellow color. This was first applied in the coloring of glassware hundreds of years ago. Without knowing the reasons, people grinded silver and gold to the nano-scale to give church windows a permanent, non-fading yellow and red color.