The recently introduced reticular nanostructured gold (RNG) consists of gold crystals that interconnect to form compact networks up to 100 nm long, 10 nm width and up to 3 nm height. The synthesis and characterization protocols of the RNG as an aqueous black colloid are here presented. Critical stages that must be performed in a very precise manner are highlighted. The high absorption throughout the visible and infrared domain confers to RNG the potential to be applied as an IR-absorbent or as a substrate for Raman spectroscopic sensors and biosensors. At this point, practical details of the Raman substrate preparation are here indicated. The whole procedure including the utensils preparation will take to complete two hours.