Tetrahexahedral (THH) gold nanocrystals bound to 24 high-index facets were synthesized through a facile colloidal chemistry by reducing HAuCl(4) in the mixture solution of N,N-dimethylformamide and poly(vinylpyrrolidone) at 80 degrees C. As-synthesized THH gold nanocrystals with O(h) symmetry were single-crystals, mainly bound to 24 high-index (210) facets. The controlled slow reaction condition made the rhombic dodecahedral gold nanocrystals transform to THH gold nanocrystals with high-index facets.