We report a simple and spontaneous synthesis of a nanoporous gold prism microassembly with highly dense skins, which is achieved just by immersing nanoporous gold into concentrated hydrochloric acid. The ligament size was coarsened to several hundred nanometers, but the crystal face orientation was still preserved. The same trends were seen in the case of coarsening by annealing; however, the morphology of the nanoporous gold prism microassembly was significantly different from the annealed nanoporous gold.