Upon adding HAuCl4 to an alkaline solution of 80 v.% water and 20 v.% ethanol, the solution turns grey, blue, purple and finally red, indicative of the formation of Au NPs with a characteristic spr around 520 nm in UV-vis characterization. The synthesis proceeds in a similar way when methanol, ethylene glycol or glycerol are used, with however different kinetics, which is attributed to the different redox and physicochemical properties of the different alcohols. The alkaline conditions favor the formation of alkoxides from the alcohols that play the role of reducing agent for the room temperature process . The mechanisms behind the NP formation are detailed in length elsewhere, and further discussed below. A first finding reported here is that Au NPs are also obtained when mixtures of [ethanol+glycerol] are used, as illustrated in Figure .