Gold in a Metallic Divided State—From Faraday to Present‐Day Nanoscience

“Very minute in their dimensions” is how Faraday described the metal particles present in a fine dispersion of colloidal gold upon observing its interaction with red light 150 years ago (see picture for a laser-light version of his experiment). This observation would come to serve as the basis for the modern nanoscience and nanotechnology of gold, including the use of gold nanoparticles in catalytic processes and the formation of self-assembled monolayers.